The people with electrical backgrounds already know well how to read multimeters and their symbols but beginners and students may get confused while reading them. So this guide is basically for people who don’t know much about multimeter usage. We’ll try to cover all necessary topics to clarify to you how multimeters generate reading and how to evaluate final results.
Although reading basic multimeter functions like voltage and current doesn’t need deep technical knowledge but there are some tips and metering factors for parameters like ohms, capacitance, milli volt, and milliamps etc. With a little learning, everyone can master meter readings.
How to read a Multimeter
The first step for reading a multimeter is to understand its symbols and ranges well. You should know ac/dc difference, auto, and manual range options, and the difference between kilo, milli, mega and micro readings. Actually, it’s all about decimal setting, we get all results in form of some number and have to adjust them according to their decimal values.
Here we can take an example of millivolts, there are 1000 millivolts in 1 volt. Suppose, if we have to convert and show1 milli volt into volts then the value will be 0.0001 volts. That’s how decimal value difference works in multimeter reading.
There’s also some difference between analog and digital multimeter reading conclusions. In analog, we have to do some more effort by calculating decimal values manually while digital meters do this task automatically and provide us immediate results.
How to read Voltage on a Multimeter
Reading voltage values by a multimeter is the simplest task we all know. One only has to adjust the meter dial to ac or dc voltage according to requirement, connecting testing leads to the source and seeing result on display.
For voltage multimeter will show values like 400 v ac , 210 v dc , 12v dc etc. Just remember one thing here that always set multimeter on a higher range than the values you are measuring.
How to read current/amps on Multimeter
Digital multimeters usually come with a lower range of current measurement from 10A to 20A. For large current digital clamp meters are the best devices because they provide safety and accuracy at their best. Readings amps in dmm are simple, result come with a symbol of ac and dc that means amperes.
Some multimeters have a resolution of milli and micro amps denoted by ma and µa respectively. 1 amp is equal to 1000 milli amps and 1000000 micro amps. If one wants to test a lower value of current then adjust the meter on milli or micro range setting.
How to read resistance value on the Multimeter
Reading an ohms value on a multimeter is little bit tricky due to large resistors values and more range availability. First step of testing a resistor is to conclude the resistor value manually by coding method if we don’t know its actual rating. Suppose if value is 870 ohms, now set the multimeter to a higher value range than 870.
We may set meter on 2000 ohms range, connect test leads with resistor and see reading. Reading should be somewhat between 860 to 880 ohms if the resistor is in good condition. Now for learning set range to 200 ohms and you’ll find no results on the screen. It’s because the adjusted range of 200 is much lower then resistor you’re testing so meter can’t calculate its value.
If we set a more high range like 2k ohms reading will be like 0.87 which actually means 0.87 k and if the setting is adjusted on 200k reading will be like 0.8 which means 800 ohms or more. It sounds confusing but with some exercise, you’ll be an expert on it.
How to read an Analog Multimeter
Reading an analog multimeter is different from a digital one. In analog meters result is shown through a needle pointing on scales. Typically they come with three scales that are for separate parameters that’s why new people may get confused.
First and lower one scale is for db (decibels) value, AC is for ac voltage, DC for dc voltage reading, Ω is for resistance measurement. Some analog multimeters also have additional functions like capacitance, micro amps and milli amps current measurements. These are denoted by their signs on the right side of the scale respectively.
Reading voltage on Analog Multimeters
After adjusting meter switch to dc or ac voltage, connect probes to the source you want to analyze. Now carefully see row having ac or dc voltage scale, it’s generally on the second row after ohm. Now if you are testing 24v set meter on 50 or 100 volts.
After connecting meter to the power source check needle movement on screen, you have to count scale lines manually here. For example, if there are 4 lines in between 0 to 50v that means every line will indicate a change of 10v. Similarly, if there are 3 lines between 50 to 70, it indicates 55, 60, and 65 v.
How to read resistance on an Analog Multimeter
Check analog multimeter dial you’ll find that the resistance range is different from other parameters. Rather than magnitude, the range is defined in form of multiples here like cross 10, 100, 1k, and 100k. It gives us a multiple of reading, if the needle is at 15 ohm while range was set on multiple of 10, then reading will be 15 * 10 = 150 ohms.
If the reading you get was 50 and range is set on 100 then result will be 5000.
There are only two things important in correct way of reading a multimeter, which are focus and numbers/symbols knowledge. With a little effort and training, everyone can do it well. We’ll suggest you that never try these things without enough education and safety training. We hope that this basic level guide helped you in understanding how to read a multimeter.
So, this is your first time using a multimeter (doesn’t matter whether it is analog or digital). The initial days or weeks of using it could be very challenging, especially when reading it. Also, the multimeter comes with various symbols and signs which you need to learn and master to ensure accurate measures and tests. Ready to get started?
- A Quick Recap about Ohms, Volts, and Amps
- Reading an Analog Multimeter Result
- How to Read the Dial Settings
- Multimeter Symbols and their Meanings
Let us begin simply. A multimeter is an essential tool that electricians and individuals rely on for checking the resistance (ohms), current (amps), and voltage (volts) of certain devices that output electricity.
A Quick Recap about Ohms, Volts, and Amps
You should understand first some basic concepts about electricity before exploring the multimeter.
Related: Our Best Multimeters for Projects & Repairs
Ohms measure the resistance amount contained within a circuit. The electricity is slowed down if the resistance is higher.
Volts measure the voltage or force amount that pushes the electrons to a circuit.
Amps determine the total amount of electrons running through a circuit.
Reading an Analog Multimeter Result
Analog multimeter is sometimes called AMM or analog multitester. It usually makes use of a galvanometer to show the reading of a current, resistance, or voltage. Some AMMs use vacuum fluorescent displays, bar graphs, and LED.
- Determine the right scale
Analog multimeters feature a needle-like placed behind the glass window. Its main role is to indicate an accurate result. There are 3 different arcs shown behind the needle – dB scale, AC and DC for voltage, and omega for reading resistance.
- Make a voltage scale reading about your range
Take a careful look at the voltage scales (either AC or DC). You should see numerous rows of numbers under the scale. Check with your preferred range.
- Calculate the value between numbers
Do not be confused with this one because the voltage scales available in analog multimeters are just similar to that of an average ruler. However, the resistance scale here is logarithmic. Meaning to say the similar distance signifies a varying value change depending upon your position on the scale.
- Multiply the resistance reading on your multimeter
Check the range setting that your analog multimeter’s dial is adjusted to. It must provide you with a number for you to multiply the reading by.
- Learn further information about the dB scale
The decibel (dB) scale is usually the smallest and lowest on the analog multimeter. You should be experienced enough to handle such a thing. It is a logarithmic scale used to measure the voltage ratio.
How to Read the Dial Settings
- Test the DC or AC voltage
The letter “V” you see on your multimeter stands for voltage. A straight line (V-) tells that there is a direct current while a squiggly line (V
) tells that there is alternating current.
- Measure the current by setting your multimeter
We measure current in amperes (A). Regardless of the type of circuit you’re testing, choose interchanging or direct current.
Direct current: A-, A—, ADC & DCA
Alternative current: A
- Find out the resistance setting
Recommended for You: Diagnose your Car with These Multimeters
The resistance setting is commonly marked by an omega symbol. This symbol is used for showing ohms. But in older multimeters, this is indicated by R (resistance).
- Make use of DC- and DC+
Depend on DC+ if you are planning to test a direct current, though it is only applicable if your multimeter already has this setting. Otherwise, turn to DC- to rectify it without having the need to adjust the wires.
- Determine other important symbols
There are so many symbols you should familiarize with, aside from the resistance, voltage, and current. For instance, the symbol -|(- shows the capacitance settings while the Hz (Hertz) measures the AC circuit’s frequency.
- Read the port labels
Multimeters come with various ports. Sometimes, they are marked with symbols that match the symbols mentioned above. For example, the black probe should always be inserted in the COM port. On the other hand, the red probe must go in the smallest current label port if you want to measure the resistance or voltage.
Multimeter Symbols and their Meanings
Fortunately, one of the most popular multimeter brands has standardized the current symbols on a multimeter. Yes, we are talking about Fluke. This reduces the extra hassle for users when using the tool.
Now, allow us to be additional assistance for helping you become acquainted with the current symbols on multimeters.
1. Hold Button
Can be found in the multimeter’s top left-hand corner. Simply press the button if you need to lock in your measurement or reading.
2. AC Voltage
One of the most common and important settings for voltage testing. The expected readings are from 100 to 240 volts.
3. Shift: Hertz
Used to measure the frequency of either an appliance or a circuit. Different circuits or equipment are intended to function at a variable or fixed frequency.
4. AC Millivolts
With a symbol mV with a squiggly line at the top of V. Use it for measuring smaller circuits with the AC setting voltage.
5. Shift DC Millivolts
It is another road symbol with 3 hyphens and a straight line over them. It utilizes DC voltage.
6. Shift Capacitance
The shift option on the diode test button. The symbol appears to be two T letters that face each other. Use it if you want to measure your capacitance.
You Might Like: Top Multimeters for DIY Electronics
7. Min/Max Button
Designed to save input values. A beep sound will be produced once a low or high value is exceeded, thus, saving the new value.
8. Range Button
Enables users to click through meter ranges.
9. Function Button
Can be compared to an Alt or Ctrl key on a computer keyboard. It is typically shown with yellow icons or text.
10. DC Voltage
Has a symbol of capital V with three hyphens on top of it and one line above that. Use it for measuring smaller circuits.
11. AC Voltage
Has a symbol of capital V with a wavy line at the top. Used for measuring the object’s voltage.
Seems like a pool of closed-end parenthesis within a row. It allows you to determine whether you have short or open circuits.
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Editor-in-Chief of the Home Maker Guide
To any professional technician, a multimeter is an indispensable tool and a fantastic piece to keep in his or her ‘arsenal’. This remarkable device performs a bunch of functions. Testing batteries, diagnosing and checking electrical circuits as well as measuring electronic parameters are just a few of those we need to mention.
But, how do you read a multimeter? Our step by step guide will tell you what to do when it comes to reading multimeter symbols in your analog and digital devices. We’ve also discovered that using the best multimeter tech gadgets, you can now measure resistance, current, and voltage with ease!
How to Read Ohms on a Multimeter
Interpreting readings on even the best multimeter devices will help you get the right value every time. Below we have put together a 3 step process to get you started. These tips are tried and tested by many technicians and related professionals. They include:
- First step: When learning how to read ohms on a digital multimeter, start by getting a resistor. Then, set the resistance function, preferably at the lowest value. Connect the two test probes to the sampling resistor to read the ohm values on display.
- Second step: checking the range of your resistor. The multimeter will only measure the resistance of up to 200ohms any value higher than that will require some range adjustment.
- Third step: With that in mind, adjust its value range to 2000ohms. Since it’s, the highest possible value even in some of the best fluke multimeter devices and it will give you a greater value than 200ohms.
How to Read Amps on a Multimeter
Amperes are used in the measurement of current and come in the abbreviation “A”. Select interchanging or direct current, depending on the type of circuit you’re working with. In many cases though, an analog multimeter lacks the power needed to test current.
Now, interpreting multimeter symbols starts by understanding the decimal adjustment concept. After all, it’s a wasted investment if you’ve just got yourself the best multimeter and can’t read the degrees of units. So, do you know how to read milliamps on a digital multimeter?
Can you remember the basic skills of reading SI units? Can you quickly interpret decimal values? If you can answer these two questions, then you’re not too far away. For most people, there’s a huge ‘technical problem’, especially when switching from a digital to an analog multimeter.
Years of work and experience have shown us that Analog amp meters huge amounts of manual calculation. This is why the best multimeter digital gadgets have become popular today. Many feel that what took hours in the calculation is now quickly turning into minutes!
How to Read Resistance on a Multimeter
Using the best multimeter devices to measure resistance is one of the simplest things you can do with this device. Once you’ve understood what each of their color codes stands for, you’re good to go! That said, there plenty of online calculators that you could also use.
However, because of limited access to the internet, using the best multimeter has emerged as a suitable option. To start, on the meter’s selection knob, set it to 20kΩ then choose any resistor and make sure the probe is its voltage measuring position. Next, hold the two pins against the resistor’s ‘legs’.
Normally, the multimeter will show symbols ranging from 0.00 to 1. For readings of 0.98, it means that the resistance value is around 1kΩ or 980Ω. Change the mode from 20kΩ to a lower value preferable 200Ω or even 2kΩ if it shows a zero reading. It’s also important to highlight that overloaded meter will show readings ‘OL’ or ‘1’, but there’s no need to panic, using the selector knob, adjust the mode to 200kΩ or 2MΩ.
Lastly, note that some resistors carry a tolerance of almost 5%. Hence, here, a color code of 10kΩ could read up to 10.5kΩ or as low as 9.5kΩ. It’s simply a problem of inconsistent manufacturing found even in the best multimeter devices but the device will still function correctly.
How to Read Analog Multimeters
Even though you may boast of having a couple of high functioning resistors and maybe the best stud finder in your work shed, an analog multimeter can still come in handy. They are inexpensive, simple, and surprisingly inexpensive devices.
Learning how to read analog multimeter scale values is a rather quick process. First, familiarise yourself with the scales needed to learn how to read a multimeter volts values. They include;
- Alternate Current (AC) and Direct Current (DC) for voltage
- Ω for resistance
- dB for scale.
So, start by choosing the most ideal scale on your meter. The good thing is the best multimeter devices; both analog and digital have an easily readable scale. For the analog multimeter, it’s a small pin-like object which moves side to side, indicating a rise and fall in the results.
With that in mind, using dc or ac, pick a suitable voltage scale. These meters have voltage scales that work just like a normal ruler. The only difference is that they use logarithmic scales where the distance represents a value change depending on your position on the scale.
When measuring resistance, on the best multimeter, for instance, use the adjusted range on your meter’s dial and multiply it with your readings. How about the DB scale? It’s the lowest in any analog device and needs a sufficient amount of time to fully understand it. What’s quite interesting about it is, it’s a scale that uses logarithms to convert the voltage into ratio!
Remember that every electrician, technician or engineer needs a multimeter. However, like experts from homemakerguide tell us; having the best tech devices is useless if you can’t use them. Luckily, learning how to read the voltage on a multimeter, current or even resistance will only take a short time.
Besides, we understand that as a professional, you need a reliable gadget and by getting the best multimeter you can rest easy. All in all, let us know what you use your digital or analog multimeter for? Is it to measure current or resistance?
You might be asking why you need to know how to use an analog-digital multimeter in this digital day. Well, there are numerous explanations for this.
In the electronics testing field, analog multimeters are a reliable tool. Experts still use analog meters for troubleshooting in some areas because of their precision and genuine RMS value conversion.
In general, here are the basic steps on how to read an analog multimeter:
- Place the probes in the appropriate connections. Select whether to test for ohms, voltage, or current first.
- Select an AC volt input. Make sure the maximum range is more than intended.
- Contact the leads to the terminals of the object you are testing.
- Check the results. The top scale is ohms. The right side indicates lesser resistance.
So, to under how to read an analog multimeter, I highly suggest that you continue reading further below.
How to Read an Analog Scale
The analog scale seems comprised of a lot of lines and numbers. This could not be very clear for beginners, so here, you will learn the basic methods to read the scale correctly:
- You can use the ohmic scale (the top line – Ω) to calculate resistance from left to right. You must multiply the scale measurement with the range presently selected based on the range specified. If your range is 1k and your pointer is steady at 5, your reading will be 5k ohms.
- You should perform the range adjustment in the same way for all quantity measurements.
- You can measure voltage range and current scales below the ohmic scale. DC voltage and current are measured next to the ohmic scale on the black line. The red line always represents AC measurements. It’s important to remember that you should evaluate current and voltage data from right to left.
Practical Activity to Read an Analog Meter
Step 1: Attach your analog multimeter to the test leads. To measure varying quantities, use the following configurations:
|To test DC voltage and current||Use an AA battery|
|To test AV voltage and current||Use an AC socket|
|To measure resistance||Use a resistor|
|To check for continuity||Use a wire|
Test leads = The materials you need to prepare aside from the analog multimeter for this activity.
Step 2: Attach the test probes to the item to be measured in each configuration and check the scale reading. We’ll use monitoring DC voltage as an example in this discussion.
Step 3: Put the probes to the AA battery’s two ends (approx. 9V). Depending on your chosen range, the pointer should fluctuate across the scale. If your battery is fully charged, the needle should be between 8 and 10 on the scale in the figure.
Step 4: Use the same method to measure the quantities in different configurations.
As previously stated, range selection and multiplication are essential for accurate analog reading. (1)
For example, if you’re measuring the voltage of a car battery with an analog-digital multimeter, the range must be greater. You’ll need to do some simple multiplication to read the final output.
If your DC volt range is 250V and the needle is between 50 and 100, the voltage will be around 75 volts depending on the precise location.
Getting to Know the Panel
Understanding the device’s panel is also crucial in reading an analog multimeter. Here is what you need to know:
First off is at the bottom left of the multimeter, you should see where you should attach your test leads.
Next is you can access the advanced options through the ports in the bottom right corner. When you need to invert the polarity of your measurement, the additional polarity switch comes in helpful. You can use the center switch to select the amount to be measured as well as the desired range.
For example, if you wish to measure voltage range (AC) using an analog multimeter, turn it to the left side of the dial.
Important Tips and Techniques
- When using analog multimeters, make sure to select a suitable range for reliable results. You should perform this should both before and during the quantity measurement. (2)
- Before doing a big test or troubleshooting operation, always calibrate your analog multimeter. I highly recommend a weekly calibration if you use your device on a daily basis.
- If you detect significant changes in measurements, it’s time to replace the batteries.
- If you are sure about the exact value of the volt quantity to be measured, always select the highest range.
We also have other multimeter learning guides. Please, check below;
(1) multiplication – https://www.britannica.com/science/multiplication
(2) quantity measurement – https://www.sciencedirect.com/science/article/
About Sam Orlovsky
I realized early on carpentry was a huge passion for me and I’ve stayed in the industry for over 20 years now. This gives me a unique ability to really be able to tell you what the best tools and recommendations are. I’m not only a carpenter but I also like machinery and anything to do with electrics. One of my career paths starting off was as an apprentice electrician so I also have a lot of experience with electrical products and anything related.
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There is a difference between a digital manual multimeter and a digital auto-ranging multimeter. Auto-ranging multimeters automatically adjust to the voltage or ohm setting needed to test the component or circuit.
With a conventional manual multimeter, the user would either know beforehand or rotate the dial to find the appropriate range. Start at a high value, and move the dial down until seeing the appropriate range. An auto-ranging multimeter automatically finds the range and indicates it on the screen for the technician. This is great when working with sensors, circuit boards, and resistors. Resistors have banded color codes that often require a chart to identify. Finding the resistance is quick and easy with an auto-ranging multimeter.
Most auto-ranging digital meters contain fuses or circuit protection for today’s sensitive circuits. This is a big plus over the older analog dial meters used in the past. If the technician were looking for 1.35 kiloohms, the meter would automatically set to kiloohms and indicate this number on the screen. An improperly set manual meter set to ohms may indicate 0.001 confusing the operator and the test results.
In the illustration above, the technician has set a manual multimeter to kiloohms and retrieved a reading of .016 K ohms. Since the meter is set for kiloohms, it is .016 x (K) or times (1000) equals 16 ohms. Just move the decimal three positions to the right. They are equal. The technician could have moved the manual lever to the ohms position and retrieved 16 Ohms. If the meter displayed .009 kiloohms, it would be indicating 9 ohms of resistance. They, too, are equal.
Most circuits, sensors, and actuators can be tested using a digital multimeter. Autoranging is just another convenient add on to a digital meter. They’re great but cost more because of the extra computer chip offering additional capabilities. They are preferred by many due to their ease of use and convenience.
For more information about ASE, visit the official ASE website at www.ase.com
How to read an analog multimeter. People utilize multimeters, nowadays, on a larger scale as compared to the past. Modern-day technology has evolved the multimeters too according to meet the required conditions.
Almost all electronic devices involve the utilization of a multimeter once a fault or drawback happens to appear in the very machine.
They are specifically designed for measuring the values of voltages in the for of different units. The units of the values might vary according to the device and sometimes, it happens because of the need you are having presently.
How to read an analog multimeter
Reading a multimeter requires proper knowledge regarding them so that you may have them read properly without getting confused.
The article includes all of the essentials needed to aid you in reading the analog multimeter. Make sure that you read it thoroughly.
The analog multimeter works on the same principle as the digital multimeter does. If you take the structure of the multimeter into your account, you will get to know the variations in the shape and form of an analogue multimeter. But there exist no variations in the working principle.
Both types generate on a similar mechanism although they have differences in the structures and methods to calculate the exact values.
You need to know the introduction of the analogue multimeter in case you are willing to get it utilized for measuring resistance or voltages in any electronic device. Make sure that you do not look down upon any of the mentioned information.
Structure of the analog multimeter
The structure of the analogue multimeter has major variances if you have it compared with the other type of multimeter. Although, both provide you with the same answers that similarity exists in the phenomenon they apply while conducting the tests.
The multimeters are hugely utilized in conducting different types of tests on multiple electronic devices. The analog multimeter consists of the following elements.
- A needle.
- A wider scale.
- Sockets or probes.
Each one of said things is mentioned in detail one after one in the veery article. The information and techniques on how to have it read are also provided in the relative section. Make sure that you do not ignore any of it.
The needle falls in the unique elements of the multimeter. Without a needle, you will not be able to read the displayed values inside the visible glass of the analog multimeter. The needle moves back and forth for helping you understand the correct and exact values of the measured resistance.
The point where the needle stops after a constant motion appears to be the readings of the multimeter. So make sure that you do not have any problem in your eyes while measuring the resistance via utilizing the analogue multimeter.
A wider scale
Right below the needle, there exists a drawn scale. The scale has the measured and calculated values of the resistance in various units. You will notice the wider range of the scale once you have an analogue multimeter. There are the values at the regular intervals mentioned on it.
It has a needle over it which we have discussed in the above section. The scale has nothing to do with the functioning system. It’s the needle that makes the scale tell you the exact values. Both are the inevitable components of each other.
Sockets or probes
Every multimeter has two sockets or sometimes probes where a connection is established with a required device. The functions of the probes include sensing and sending the signals forward to get the measured values. Make sure that you have proper knowledge about the units while taking measurements.
One of the easiest ways of measuring resistance is by using a multimeter. A multimeter is not only used to measure the resistance accuracy and whether it functions appropriately but also measuring other measurements such as amperage and voltage. Therefore, you can use a multimeter to find the resistance of an indefinite component. Likewise, you can also choose to use it to examine electrocuted or open circuit, with this vital as it allows you to measure resistance which is very crucial.
The use of digital multimeters is a lot easier to use as well as to read in comparison to the analogue multimeter. This is because it has a screen that displays the reading value of resistance, which is usually a figure close to 2 decimal places on your measurement scale. However, it would help if you took note that digital multimeters vary from one model to another though not so much, so you should always make you make good use of your manufacturer manual script.
- Reading the digital display
- Read the resistance value
- Check OL or 1 to show that your resistance range is too minimal
- Switch on your multimeter
- Select the resistance function
- Ensure you remove the components you want to examine from the circuit
- Examine the resistance of your electrical device using the leads.
Furthermore, you are encouraged to exercise safety measures to safeguard your wellbeing and some of the tips you need to observe include:
- The circuit being examined should not be powered on as this could lead your multimeter to get damaged and also interfere with the reading value.
- Only test for resistance when the component you are running a test on is unplugged from the circuit.
- Keep your fingers out of the measuring sight as this could probably alter the reading value displayed on your multimeter resulting in an inaccurate measurement.
Reading the digital display
Look for a symbol ‘’M’’ or ‘’K’’ located next to the omega to come up with the scale of your reading value. Usually, the label on your digital meter shows the ohm level. If the reading value displayed on your multimeter ranges either in mega-ohm that is 1,000,000 ohm or in kilo-ohm that is 1,000 ohms, then you are likely to have an addition symbol of K or M particularly in front of your omega sign.
Read the resistance value
It is appropriate that you acquire basic knowledge and skills on how to handle the multimeter, especially when it comes to knowing the scale of your ohmmeter. Therefore, having a good understanding of the resistance reading value is a necessary thing in the readout procedure of the multimeter. On the digital multimeter, the numbers are usually displayed in front or at the centre of the multimeter screen, with this number typically close to 2 decimal places.
Resistance is a measurement that is based on minimizing the amount of energy passing through a material. In case the reading value displayed is high, then consider having a maximum resistance value, hence meaning you need to add more power to regulate the element in your entire circuit.
Check OL or 1 to show that your resistance range is too minimal
Some digital multimeter do not come set automatically, so it is upon you to set it the range. Thus, you should start by setting the maximum range as you head towards the lower ranges until your multimeter displays a reading. Apply this even if you are sure of the range of the element you are examining.
Switch on your multimeter
This depends on the kind of multimeter you are probably using. However, switching on the multimeter is usually easy since you press the switch that indicates turn on. For more detailed information on how to set the resistance, you should check out the user manual.
Select the resistance function
An ohmmeter is typically found the multimeter suite. However, there is a variation when it comes to choosing the resistance function since the multimeter also differs in terms of the model. Thus, you need to check for a rotating dial to alter your settings, and in case you experience any difficulty, you can always refer to your user manual.
Ensure you remove the components you want to examine from the circuit
When looking to carry out tests to measure resistance, you need to examine whether your component is faulty, and this will always lead to you removing it from the circuit. After that, examine your component by holding both leads to 2 poles of your component, and this will give you an appropriate reading.
Examine the resistance of your electrical device using the leads.
Once you are ready to examine the resistance reading value of your component, hold the test leads of your device, you are examining. The leads are two thin silver wires coming out of your component. How you hold does not really matter as you will still find out the results. In case you find it tricky check your manufacturer script as mentioned earlier above
You can also choose to work with an auto-range setting if you want. Most digital multimeters have been set automatically, so there is no need for you to panic because everything is usually set. This has been simplified for the purpose of serving your time. However, it is typically inbuilt, or you can also choose to have it from your millimeter’s menu. You can decide to commence with the maximum range of your digital multimeter maybe you might get an accurate reading.
Therefore, hold your multimeter’s probes against the circuit’s side as you observe and take the readings. Your reading is likely to stay at zero on a maximum range. However, if your range is too minimal, it is likely to make the needle to move suddenly hence causing damage. So, for you to get an appropriate reading value, it is good that you use your range adjustment knob on your digital multimeter always, lower the range until you get the correct reading value.
The above information will guide you on how to read ohms on your digital multimeter. Whereas sometimes this seems to be somewhat challenging, with the necessary skills and knowledge, all this is usually very simple and straightforward. However, if you are experiencing any troubles, you can always hire a professional to help you out or refer to the user manual. Consequently, you will be able to diagnose what the possible issue might be.
Measuring resistance on a multimeter can be really easy with some very simple steps. Resistance, otherwise known as ohms, is needed to be measured for many reasons.
You may want to check resistance in order to see the accuracy of a resistor. Or you may not know the resistance of a circuit and want to know what it is.
Most circuits are color coded which makes it easy to determine their resistance, but in any case, you can always check this using your multimeter.
No matter what your reason for measuring resistance, your digital multimeter is a great piece of equipment to do it with. You can utilize most of the Fluke brand devices to measure resistance including some of my favorites like the Fluke 116, Fluke 117, Fluke 87V, or Fluke 3000 FC.
What you will need
- Digital Multimeter with the ohms setting Ω, like Fluke 116 (see on Amazon.com)
- A socket or the item to be measured
How to measure resistance
There are a few simple steps to measure resistance with your digital multimeter:
- Pick the item you want to measure where resistance may be found.
- Select the appropriate ohms setting which you will know it because the section will show this sign: Ω
- You may not know right away which range to use when selecting the ohms setting, but if later on when you start to measure your multimeter show something strange like a 1 and a bunch of blank spaces (like this: 1__._), you’ll know that it’s too low and you’ll have to increase the range.
- For the probe leads, you’ll need to modify them when measuring resistance. The black lead will stay in the socket that says COM which is normal. For the red probe lead, you’ll need to make sure it’s put in the socket which shows the ohms symbol (Ω).
- Next, you’ll want to test if the meter is functioning properly by taking your red and black probe leads and touch the metallic parts together. The multimeter should say almost zero, but usually will say 1 or 2. If your multimeter shows a high number, then something is wrong with your multimeter and you probably will not have accurate results.
- Again, make sure your resistor is not connected to any circuit or power source.
- Take your black and red lead and connect them to opposite ends of the object you are looking to check resistance on (the resistor).
- Your device will then show you a number which is your resistance.
Things You Should Know
There are a few different setups that you may have when doing resistance measurement so it’s important to know the following:
- Disconnect Object: Before you can start measuring resistance, you need to make sure that there is no electricity flowing through an object. If electricity is flowing through it, it will not measure resistance properly. First disconnect the device from any power source prior to testing its resistance.
- Remove from Circuit: Another important reminder is to ensure that the device/resistor is not a part of a circuit as well. It is best to remove the resistor from the circuit prior to testing it for resistance as the additional paths within the circuit will affect the results of the resistance as they will have resistance as well.
- Analog Meter: If you are using an analog multimeter, the steps are the same in both instances, but the device may look different with the needle showing you the actual measurement.
Resistance is an easy measurement to make. If you’re looking for an instructional video, this one is great to check out:
It’s always important when you’re finished making your measurement to turn the multimeter off as when it is put in this setting an electrical charge is being sent constantly through the probes.
As well if you need your readings saved, many multimeters have a “hold” button which will save the reading if you need to refer back to it at a later time.
One of the most basic household purposes to use a multimeter is battery testing. The simplest way to check a (AA) battery, is generally used in remote control of the TV. To check whether it is in good condition or not, connect it to a multimeter’s test probes and measure its voltage or amperage. If you have wondered how to test a battery with a multimeter, this guide will walk you through it.
We will use a pocket digital multimeter because we need a simple tool to test and a 9-volt battery for this guide.
For more knowledge about measuring other measures such as resistance or capacitance, check out our other articles.
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How to Test a Battery:
The fundamental purpose is to check if a battery is capable of providing enough amperage to a load.
In this case, We will consider the load as a TV remote control (RC). For a nine-volt battery, we will test both the voltage as well as the current.
How to Check Battery Voltage Using a Multimeter?
We are setting up a multimeter, along with the battery, to test. We will use a 9-volt transistor battery for this guide.
First, we will measure the voltage of the battery. Second, we will measure the current. To do this, Move the selector dial to select D/C voltage measurement. Since the battery generates D/C power, therefore, we will measure D/C voltage.
We previously knew that the battery’s voltage is 9 Volt maximum so we will point the dial to a higher range of 20 Volts.
Connect the test probes – black with negative, red with positive – to the battery and check the display.
The display should read a value that is just short of 9Volt. Because this battery has been in use for some time, it shows a reading of 8.74Volts, which is still sufficient to supply current to the load.
For a different (drained) battery, the reading looks like this
In most cases, this voltage measurement of a battery is enough to understand that it’s working perfectly.
However, to assure that it can supply enough current to a load; therefore, we also measure the ampere in milliampere-hour (mAh).
How to Measure Battery Amps With A Multimeter?
Select the D/C current function using the dial and keep it at 200mA since the battery’s amperage will be around 100mAh.
Connect the test probes similarly, before as we did for voltage measurement and check the display.
It could fluctuate around 98.3, which indicates that the amperage is 100mA – enough to run the small PCB of the TV remote control.
It would be unmistakable that testing a battery using a multimeter is one of its most accessible applications.
So, whenever your TV or any functioning remote control starts acting funny, you can immediately take out your multimeter and start getting some answers.
Indeed if the battery shows a good reading, there can still be an issue while connected to a load.
There are some multimeters open in the market that resemble a load to test the battery. These multimeters can be a great addition to your toolbox.
While operating, if a battery has a voltage level that is half of its initial rating, it might be a good idea to get a new one; why? Because batteries drain out faster once they reach half-life.
You may also use a simple voltmeter or an analog multimeter to test batteries. These multimeters will give you an accurate, direct reading on the scale instead of a digital display.
How to use a multimeter to test a car battery?
You may use a multimeter to test heavy-duty car batteries or alternators that might be giving you hazards such as delayed ignitions or dim headlights.
In addition, you can check the health of your battery through the dashboard display, and sometimes the battery load can be empty, leaving you no choice but to open the bonnet. That is where the multimeter comes into the picture.
The process is similar to what we did before, connect the test probes in black and red to the battery’s terminals and observe the reading.
Car Batteries have different ratings for each make, it varies from car to car, but a good battery would be 15V to 20V D/C. In our case, we have the 20 Volt range battery.
It is a good idea to turn on your headlights for a few minutes before checking the battery so that this will paddle off any surface charge that it might have.
Hence, the reading we observe is 12.78V, which is suitable for a one-year-old car battery.
If the observed reading is more than the minimum value (around 12 Volts), then it is evident that the battery has a reasonable charge.
However, this process alone is not enough to understand whether it is in good condition or not. You still need to examine if your car can firmly pull power.
So the simplest way to check that is to test the cold cranking amps (CCA) that trigger the ignition. Most car batteries are assumed to be suitable for 3-4 years approximately.
How To Test The Cold Cranking Amps of a Car Battery with a Multimeter?
Set the multimeter probes connected to the battery terminals and switch on the ignition.
You required extra support for this specific task because you need to check how the reading fluctuates while cranking up the ignition. The value should drop (around 10V) in an ideal scenario and return to a higher value (more than 12V).
And if the reading stays constant while the engine is still running, you can verify that the battery is in fresh and new condition.
We have observed our reading is 14.73, which is also an excellent number for the cold-cranking amps value. If the initial reading is around 5V, your battery is working but will go bad. If the measured value is below 5V, now you should replace your battery.
Frequently Asked Questions
The unit of electric current measurement is amperage, whereas if we multiply the amperage amount of current by a time, this is called Amp Hour.
Here are some factors that battery can last long:
Quality, Proper alternator voltage output (the alternator has to work correctly), Power surges and short circuits (for instance, improper jump starting).Ground connection from the car battery to the car. How much the battery is used, Outside temperature, physical damage and maintenance of the battery.
You are testing a battery, whether a car battery or a AA battery. As you can see, it is effortless and quick. So the solution is to try it out with different batteries that might be lying around (in your house or lab) to understand different charge positions.
We hope this article will guide you and has been helpful on how to test a battery with a multimeter.
Measurement of Frequency with a Digital Multimeter
Frequency is the number of cycles completed in one second of time. There are different kinds of multimeters that can measure frequency. Alternating current and other electrical signals possess frequency that affects the operation of a device. By using a multimeter, we can measure multiple quantities such as voltage, current, resistance, capacitance, frequency temperature and continuity, etc and testing electrical and electronic components such as resistors, capacitors, diodes, transistors and cables & wires etc.
In this article, we are going to study how a multimeter measures frequency and what are the factors that affect its reading.
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A digital multimeter that can measure frequency has a peak-detection circuit. The meter measures the time between the two consecutive crests (peak of waveform) using the peak-detection circuit. it detects the peak of the input waveform and starts the timer. When the next peak of the waveform is detected, it stops the timer. The meter calculates the frequency using the time between the two crests of the waveform.
Any digital multimeter that can measure frequency has “Hz” written anywhere on the dial and upon the ports where probes are inserted. It may also share a spot on the dial with “VAC” or “V
There are two methods for measuring frequency on a multimeter. If your multimeter has a dedicated spot on the dial, then follow this method.
- Turn the meter ON by switching the ON/OFF button.
- Turn the dial to “Hz”, it shares a spot on the dial with any other function such as “VAC or V
”. Pressing the “shift” button access the secondary option and starts measuring frequency. “Hz” appears on the display to confirm the meter has switched to frequency measurement.
- Some multimeters have a dedicated spot for frequency measurement on the dial that has “Hz” written on it.
- Insert the black probe first into the “COM” port.
- Then insert the red probe into the port having “Hz” written on it.
- Connect the black lead first and then the red lead to the point of measurement.
- Note the reading from the display.
- If your multimeter has different ranges, reduce the range to get an accurate reading. Most multimeters have “auto range” button to select the proper range based on the reading.
- When finished, remove the red lead first and then the black lead.
- Remove the black and red lead from the meters ports.
- Turn off the meter or turn the dial to “voltage measurement” to avoid any potential damage in case of quick reuse.
Some multimeters have a separate button for “Hz”. For such meters, follow the following procedure.
- Turn the meter ON by switching the ON/OFF button.
- Turn the dial to “VAC or V
- Insert the black probe first into the “COM” port.
- Then insert the red probe into the port having “V Ω” or “Hz” written upon it.
- Connect the black lead first and then the red lead to the point of measurement. Swapping the leads does not affect the reading.
- Press the “Hz” button to switch to frequency measurement.
- Note the reading from the display.
- If possible reduce the range to get an accurate reading. Auto-range feature selects proper range based on the reading.
- When finished, remove the red lead first and then the black lead.
- Remove the black and red lead from the meters ports.
- Turn off the meter or turn the dial to “voltage measurement” to avoid any potential damage in case of quick reuse.
Problems Incurred during Frequency Measurement
There are many problems that can affect the frequency reading of a multimeter. We can reduce some of them to get an accurate reading.
Range of the Meter
The datasheet of a multimeter shows the lowest and highest frequency the meter can accurately measure. If the input frequency falls below the range, the multimeter may display a reading close to the actual reading but not accurate enough. The same thing will happen to a higher frequency above the range. The meters may not keep up with the actual frequency and display lower readings or show “OL” overload.
Therefore, it is necessary to know the range of the meter and the approximate frequency of the input signal.
Distortion in Input Signal
If the input signal has frequency distortion, it can affect the reading of the multimeter and cause uncertainty in the reading. The reading may also fluctuate. The signal can be filtered from noise by using a low pass filter.
Sometimes, the multimeter may pick up the frequency reading without probes touching the line. it may occur due to the unshielded lines that act as antennas to radiate the EMI (Electromagnetic interference). The meter picks up the signal, amplify and measure It and display the reading. It may or may not be accurate. Therefore, it is best to physically connect the probes to the wire.
Why do We Measure Frequency?
Measuring frequency is important because circuits and machines are designed to operate at specific frequencies. They either operate at fixed frequency or variable frequency where the output depends on it.
One such example is an AC electric motor whose speed is directly proportional to the frequency of the mains supply. A motor or transformer designed to operate at 50 Hz will run at a higher speed if connected to a 60 Hz supply. Similarly, a 60 Hz motor and transformer will be slower if it runs on a 50Hz supply. Here is an interesting question for you 🙂 Is it Possible to Operate a 50Hz Transformer on 5Hz or 500Hz Frequency?.
This is measured using a digital multimeter and indicates if an electrical circuit is complete or broken. A component’s resistance relates to the manufacturer’s specification.
By following these steps to complete the resistance test:
- Make that the component under test is isolated from the rest of the circuit. Isolate the component by removing it from the circuit or using an open switch.
- The selector dial should be set to Ω.
- Connect Simply the test leads and probes to the component terminals.
- Check the readout window to obtain the Ω reading.
- Compare the results to the manufacturer’s Ω specifications. Resistance is not an issue if the readings match the component. If the component is a load, there should be resistance that matches the manufacturer’s specs.
- When the reading is either infinite (I) or overloaded (OL), the component is open.
- If the reading is 0, then the component is stopped- If it’s a load, it’s an internal short.
- Double-check all power is turned off on the circuit you’re testing.
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A Complete Introduction to Ohm’s Law?
Ohm’s law is used by engineers to calculate the resistance of a circuit. This formula was discovered by Joseph Henry Ohm, who was born in 1791. He discovered the law while working on the electromagnet for an electric generator which was being developed at his employer’s laboratory in Germany at that time. In 1817 he published his findings as “A New Principle of Electromagnetic Resistance.
Ohm’s law is a fundamental law of physics. It states that electrical resistance is directly proportional to the current and inversely proportional to the voltage. Ohm’s law also describes how to measure resistance in terms of ohms (units: Ω). It is not just a mathematical equation, but also an engineering principle that describes how two different materials can be connected in series or parallel.
Ohm’s law describes the relationship between voltage and current in a circuit. It is used to describe the relationship between power and current in many different circuits, such as electric motors, transformers, computers, etc.
Ohm’s law is used in electronics to describe how currents flow through electrical components such as resistors and capacitors. It is also used in electronics to calculate voltages, currents, and power dissipation.
Resistance is a measure of the electrical resistance of an object. It is expressed in ohms. Resistance can be expressed as resistance value or by a number called ohm’s law (R = I × V).
Resistance is measured in ohms and it gives us a way to express the magnitude of current flow through an object, which can be measured with a multimeter.
The resistance value for an object is usually expressed as R, where R is the resistance value and I represents the current flowing through that object. The current flowing through an object can be measured with a multimeter.
The purpose of this test is to determine if the component is defective and can be replaced or repaired.
What Does An Ohm Reading Mean?
An Ohm reading is a measurement of electrical resistance. It is the resistance of an object when a current is applied to it. The resistance will increase as the current increases and decrease as the current decreases. Ohm Reading is the measurement of the resistance of a conductor between two points. Ohm Reading is calculated by measuring the resistance at two points on a wire, one at one end and another at the other end.
Resistance is measured in Ohm’s Law:
The resistance of a circuit can be measured in several ways, such as:
1) Ohm’s law: The formula for calculating the resistance of any circuit, based on the number of turns and length of wire used.
(2) Ohm’s law for resistors: This is an easy way to calculate the resistance value when you have only two resistors
(3) Ohm’s Law for Inductance: This formula allows us to calculate the inductance value when we have two inductors
(4) Ohm’s Law for Capacitors: This formula allows us to calculate capacitance value when we have a capacitor and an inductor
Frequently Asked Questions:
Multimeters (also referred to as “resistance” testers) are devices that measure the resistance of a circuit. They can be used in a wide variety of applications
You can use Ohm’s Law to calculate resistance if you know the total current and voltage across the entire circuit: R = V / I.
We learned how to measure resistance in this article. Measuring resistance (ohm) is a simple procedure if you are familiar with using a multimeter.
Furthermore, since you’ll be working with potentially dangerous parameters, you must take caution. So, go with a safe that has advanced functionality.
A multimeter is one device that you should have if you like to work with electrical systems. It can be useful in more ways than one, which makes it a great investment. While it can be beneficial, however, this will only be the case if you know how to use a multimeter properly, which will allow you to make the most out of its functions.
In a nutshell, a multimeter is simply a device that will provide you with several measurements of electricity. It is a multi-functional tool as it can provide you with more than just measurements. To be specific, it will be useful for the measurement of voltage, current, and resistance. Clueless on how to use this equipment? Keep on reading and learn from the insights that we will be sharing.
How to Use a Multimeter in Measuring Voltage
Voltage refers to how hard electricity will be pushed in a circuit. The harder the push of the electricity is, the higher will be the voltage. Voltage is indicated in “V” and measured as volts. Here is how you can use your multimeter for the measurement of voltage:
- Start with connecting the multimeter to the circuit. Insert the black probe into the COM port, which is the common terminal, and the red probe in the VΩmA port, which is specifically the port for the measurement of voltage and ohms. Before doing this, make sure as well to turn off the power to the wire or circuitry.
- Determine whether you are measuring AC or DC voltage. Turn on the dial on the voltage that you intend to measure.
- If you are measuring AC voltage, you can now place it in the component without the need to pay attention to polarity. On the other hand, if you are measuring DC, be sure to observe polarity.
- Power the equipment and read the display that you can find in the multimeter.
How to Use a Multimeter in Measuring Current
Current, on the other hand, refers to the amount of electricity that flows in a circuit. If there is high electricity flowing, the current should also be high. To measure current with a multimeter, here are the things you have to do:
- To start with, turn off the supply of electricity from the circuitry where the measurements where will be made. Multimeters have two sockets with different milliamperes. Choose which one is suitable.
- Select the setting from the multimeter that is meant to measure current. Follow this up by breaking the circuit. While placing the probes in the breaks, be sure to pay attention to polarity. Connect the red probe on the positive break and the black probe on the negative break.
- Turn on the power supply. This will let electricity pass through the circuitry, making it possible for the multimeter to make the appropriate measurement.
- Read the display to know the current in the circuitry. In the case of some models, there is a feature wherein you can touch the Hold button for the readings to stay on the screen.
How to Use a Multimeter in Measuring Resistance
Expressed as ohms, resistance refers the obstruction that the electricity experiences as it flows through a current. If there is a higher resistance, this means that electricity is finding it more difficult to enter the current. Here is how to can use the multimeter in the measurement of resistance:
- Connect the appropriate circuit in the multimeter. Attach the black probe to the common terminal. On the other hand, attach the red probe to the terminal for the measurement of voltage and resistance.
- Turn the selector knob to choose the specific setting for the measurement of resistance. In some models, this may be represented by the Greek symbol of omega, which means ohms.
- Turn off the supply of power.
- Place the probes on the circuits that you will measure. Make sure to remove the resistor from the circuit board prior to measurement. Otherwise, there is a high likelihood that the result will be inaccurate.
- Read the measurement on the display.
To make the most out of this multi-functional device, it is important that you learn how to use a multimeter. It does not take an expert to figure this out. Nonetheless, it is important that you follow the right steps to be safe, and more importantly, to be sure of ending up with accurate measurements. Finally, if you don’t have a multimeter, read our reviews to pick the best one.
About The Author
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To start, let’s measure voltage on a AA battery: Plug the black probe into COM and the red probe into mAVΩ. Set the multimeter to “2V” in the DC (direct current) range. Almost all portable electronics use direct current), not alternating current. Connect the black probe to the battery’s ground or ‘-‘ and the red probe to power or ‘+’. Squeeze the probes with a little pressure against the positive and negative terminals of the AA battery. If you’ve got a fresh battery, you should see around 1.5V on the display (this battery is brand new, so its voltage is slightly higher than 1.5V).
If you’re measuring DC voltage (such as a battery or a sensor hooked up to an Arduino) you want to set the knob where the V has a straight line. AC voltage (like what comes out of the wall) can be dangerous, so we rarely need to use the AC voltage setting (the V with a wavy line next to it). If you’re messing with AC, we recommend you get a non-contact tester rather than use a digital multimeter.
What happens if you switch the red and black probes? The reading on the multimeter is simply negative. Nothing bad happens! The multimeter measures voltage in relation to the common probe. How much voltage is there on the ‘+’ of the battery compared to common or the negative pin? 1.5V. If we switch the probes, we define ‘+’ as the common or zero point. How much voltage is there on the ‘-’ of the battery compared to our new zero? -1.5V!
Now let’s construct a simple circuit to demonstrate how to measure voltage in a real world scenario. The circuit is simply a 1kΩ and a Blue super bright LED powered with a SparkFun Breadboard Power Supply Stick. To begin, let’s make sure the circuit you are working on is powered up correctly. If your project should be at 5V but is less than 4.5V or greater than 5.5V, this would quickly give you an indication that something is wrong and you may need to check your power connections or the wiring of your circuit.
Set the knob to “20V” in the DC range (the DC Voltage range has a V with a straight line next to it). Multimeters are generally not autoranging. You have to set the multimeter to a range that it can measure. For example, 2V measures voltages up to 2 volts, and 20V measures voltages up to 20 volts. So if you’ve measuring a 12V battery, use the 20V setting. 5V system? Use the 20V setting. If you set it incorrectly, you will probably see the meter screen change and then read ‘1’.
With some force (imagine poking a fork into a piece of cooked meat), push the probes onto two exposed pieces of metal. One probe should contact a GND connection. One probe to the VCC or 5V connection.
We can test different parts of the circuit as well. This practice is called nodal analysis, and it is a basic building block in circuit analysis. By measuring the voltage across the circuit we can see how much voltage each component requires. Let’s measure the whole circuit first. Measuring from where the voltage is going in to the resistor and then where ground is on the LED, we should see the full voltage of the circuit, expected to be around 5V.
We can then see how much voltage the LED is using. This is what is referred to as the voltage drop across the LED. If that doesn’t make sense now, fear not. It will as you explore the world of electronics more. The important thing to take away is that different parts of a circuit can be measured to analyze the circuit as a whole.
What happens if you select a voltage setting that is too low for the voltage you’re trying to measure? Nothing bad. The meter will simply display a 1. This is the meter trying to tell you that it is overloaded or out-of-range. Whatever you’re trying to read is too much for that particular setting. Try changing the multimeter knob to a the next highest setting.
Why does the meter knob read 20V and not 10V? If you’re looking to measure a voltage less than 20V, you turn to the 20V setting. This will allow you to read from 2.00 to 19.99.
The first digit on many multimeters is only able to display a ‘1’ so the ranges are limited to 19.99 instead of 99.99. Hence the 20V max range instead of 99V max range.
Steps for measuring dc voltage with a digital multimeter
- Then insert the red probes into the V Ω jack. When finished, remove the probes in reverse order: red first, then black.
- Connect the test probes to the circuit: black to the negative polarity test point (circuit ground), red to positive test point.
Note: Most modern multimeters automatically detect polarity. When measuring dc voltage, it is not critical for the red lead to contact a positive terminal or black to touch negative. Just recognize if the probes touch opposite terminals, a negative symbol will appear in the display. With an analog multimeter, red leads should always touch a positive terminal and black a negative terminal. Otherwise, damage to the meter will occur.
- Read the measurement in the display.
Other useful functions when measuring dc voltage
- Modern DMMs default to Autorange based on the function selected on the dial. To select a specific fixed measurement range, press the RANGE button multiple times until the desired range is selected. If the voltage measurement falls within the range of a lower dc millivolts setting, follow these steps:
- Disconnect the test probes.
- Change the dial setting to dc millivolts.
- Reconnect the test probes and read the measurement.
- Press the HOLD button to capture a stable measurement. It can be viewed after the measurement is complete.
- Press the MIN/MAX button to capture the lowest and highest measurement. The DMM beeps each time a new reading is recorded.
- Press the relative (REL) or delta (?) button to set the DMM to a specific reference value. Measurements above and below the reference value are displayed
Note: Avoid this common technician mistake: inserting test probes into incorrect input jacks. If measuring dc voltage, be certain to insert the red probe into the input jack marked V, not A. The display should show the dcV symbol. Placing test probes in A or mA inputs and then measuring voltage will create a short in the measurement circuit.
Voltage measurement analysis
- Voltage measurements are normally taken to a) establish that voltage exists at a given point and b) ensure that the voltage is at the proper level.
- AC voltages can vary widely (between -10% and +5% of the power source rating) and cause no problems in a circuit. Yet with dc voltages, even small variations may indicate trouble.
- The exact amount of acceptable dc voltage variation depends on the application. See chart below for an example.
- In some dc applications, large dc variations are not only acceptable, but intentional.
- Example: The speed of dc motors can be adjusted by varying the amount of dc voltage supplied. In this application, the measurement of dc motor voltage depends on the setting of the voltage regulator.
- When taking and comparing dc voltage measurements, refer to manufacturer’s specifications for specific values in the circuit.
As shown in the chart above, a fully charged auto battery rated for 12 volts may have an open-circuit voltage ranging from 11.9 V to 12.6 V (typically 2.2 V per cell).
- A measurement of 11.9 V indicates a dead battery.
- A measurement of 12.6 V indicates a battery with a 100% charge. In-between measurements indicate a charge of less than 100%.
- A battery with a slightly higher voltage measurement (3% to 5%) is much better than a battery with a lower measurement. A dc voltage variation below the normal rated voltage indicates a problem.
Ac and dc voltage measurements
- In some applications, dc voltage measurements may be taken in circuits that include ac voltage.
- To ensure maximum accuracy of a dc voltage measurement, first measure and record the ac voltage. Then measure dc voltage by selecting a dc voltage range (using the RANGE button) that is the same or higher than the ac voltage range.
- Some DMMs can simultaneously measure and display the ac and dc components of a signal. The DMM display can show results three ways (see illustration below):
- The ac portion of the signal appears in the primary display and the dc portion in the smaller secondary display.
- The dc reading can be switched to the primary display while the ac drops to the secondary (on most DMMs).
- The combined AC+DC value – the signal’s equivalent rms signal value.
Reference: Digital Multimeter Principles by Glen A. Mazur, American Technical Publishers.
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With so many battery operated products in the house, multimeters have become the need of this day.
Today, we are here to tell you how to use one correctly. From TV and AC remotes to battery operated lights, there are a lot of products that need proper functioning cells to run. Even our cars cannot run without cells.
With multimeters available on the internet and in shops, it is easier to buy one and take care of all your batteries at home itself. As such, you would not need to visit a mechanic at a garage.
But if you are confused about buying a multimeter because you do not know how to use it, here’s a guide that will provide the details. Read on to learn how to measure voltage levels for different types of cells. Also, we will tell you how to understand when to buy new batteries because they are running out of juice.
Let’s turn on the ignition and proceed!
How to Check Battery Voltage Using a Multi-meter
Firstly take a multimeter and place it on the table. Also, bring in the battery you want to test. We will explain the process with a 9-volt battery for this guide. To correctly measure the voltage, turn your switch dial to DC voltage measurement.
This needs to be done because a battery generates DC power, and this means you will need to measure it with the same unit. So it is essential to know the maximum voltage of the battery. Set the dial to 20 volts, which is the maximum range.
Connect the test probes to your cell, with the black wire meeting the negative. The red wire should meet the positive and then check its display. If you get a number which is higher than 7 for a 9-volt battery, it is still usable, and the cell will last for some more time.
On the other hand, if it is a dead battery, it would show results below 1. If that is the case, it is time to buy a new one. Mostly, it is enough to just check the voltage to get a clear understanding of the battery.
But if you have to ensure that it can supply sufficient current to a load, you would need to measure the amperage in milliampere-hour (mAh). We will discuss this in the next part.
How to Measure Battery Amps with A Multimeter
So here we will talk about how to get accurate measurements of the current of a battery. The average amperage of the battery would be somewhere around 100 mAh. So before measuring, turn the dial to DC function and keep it at 200 mAh.
Again connect your test probes in a similar way where the black wire meets the negative. The red one should connect to the positive. After you are done, check the reading on the display.
If it fluctuates somewhere around 100 mAh, it is working alright and will run any small device efficiently. We tested it on our TV remote control battery, and we got 98.3 on our display, which was a satisfactory result.
While testing your battery, if you find the number to be below half the voltage level of any cell, it is time to replace it. This is because once a battery reaches its midpoint, it starts to drain away quickly.
If you do not have a digital multimeter, you can also try using a simple voltmeter or an analog multimeter. These do not come with a digital display but will let you take accurate measurements with a facility to read it from the scale directly.
A digital variant is easier to use and will always be the preferred choice, but again, it is not the only way to get the job done. There are a number of multimeters available in the market today that simulate a load to test the battery. These devices can be great additions to your tool collection.
How to Use A Multimeter To Test A Car Battery
If your car battery is causing problems or you have an issue with dim headlights or delayed ignition, a multimeter can come to the rescue. This product can also be used to check the health of heavy-duty car batteries or alternators.
Though you can already see the battery level on your dashboard display, it may so happen that the battery has completely drained out. In such a case, you would have to open the bonnet to get access to the battery, and that’s when you need a multimeter.
The process is the same as above. You would need to connect the probes to the battery terminals. Then proceed to check the reading on the multimeter display.
The battery ratings vary a lot from car to car, but choosing 15-20 Volt is good enough. We selected 20V before proceeding to measure the level. Allow us to give you a piece of advice here – you should keep the headlights on for a few minutes before checking the battery. This would drain away any remaining charge.
If your measurement is more than the minimum value, which is usually 12 volts, the battery has a good charge and will last. However, this is not the only way to judge if the battery is in perfect condition. One also needs to check if the car is able to draw power successfully.
A quick way to come to a conclusion is to test the cold cranking amps (CCA) that trigger the ignition. Most car batteries tend to function well for 3-4 years before deteriorating.
How To Test The Cold Cranking Amps (CCA) of a Car Battery
To test the cold cranking Amps, keep your multimeter connected to the battery terminals and then fire up the ignition of your car. This is a job for two people, where one needs to take control of the ignition while the other checks for fluctuations while the engine is cranked up.
The ideal situation would be if the reading drops to 10V but then returns to a higher value around 12 V. If the reading stays constant after the initial value drop, then you would know your battery is in perfect condition. The engine needs to be running throughout the process.
If the initial reading is around 5V and not below it, you should know that the battery is slowly dying and would not work for long. Also, if the reading is way below 5V, then it is time to replace the cell.
Make sure that you do not try to do it all by yourself. Take another person’s help because if you try to handle both the engine as well as the measurement, you may end up with an incorrect reading.
Now you know how to go about using a multimeter to test batteries. It is fairly easy once you are well-versed with the process.
However, we strongly recommend that you practice on different cells to get the hang of it. Maybe consider practicing with the different batteries used for household items like the remote, video game, torch, and even a battery from a lamp. The more you play around with different cells, the better you understand various charge positions.
We hope this guide was helpful in explaining to you how to test a battery with a multimeter. If you still face any problems, do let us know in the comments section below.
No more scratching your head at malfunctioning appliances. With this guide, you’ll learn the ins and outs of troubleshooting your home and household electronics using one of your toolkit’s handiest instrument.
By Glenda Taylor and Bob Vila | Updated Mar 15, 2021 1:34 PM
Once reserved for engineers and electronic technicians, multimeters—sometimes called “multitesters”—have come down in price and size, making them indispensable for homeowners who have basic knowledge of circuitry. When troubleshooting problems with small appliances, smart-home modules, speaker systems, or just about any other electronic item, a multimeter will be among the most valued tools in your arsenal.
If you’re new to multimeters, these gadgets may seem daunting at first. Learn the basics, however, and you’ll soon be able to perform a number of diagnostic tests on your own. Because multimeters vary from model to model, be sure to study your specific unit’s operating manual before you get started.
Two Types of Multimeters
Analog multimeters, or volt-ohm-milliammeters (VOM), have been around for decades and can still be found, affordably, at any do-it-yourself-type store. The new kids on the block—digital multimeters (DMM)—offer greater precision with decimal point readouts, even enhanced functions, such as the ability to auto-detect alternating current (AC) or direct current (DC).
Applications and Limitations
Both VOM and DMM models measure voltage, resistance, and current, replacing the need for individual voltmeters, ohmmeters, and ammeters. While you can test household voltage with a multimeter, electrical-current-testing is limited to low-voltage circuits, such as small direct current (DC) motors or low-voltage alternating current (AC) appliances—your thermostats and doorbells, for example. To avoid blowing a fuse, destroying the multimeter, or risking injury, do not attempt to test current higher than the maximum allowed for your unit.
Among other things, multimeters can determine:
- Available battery charge
- Voltage at an outlet or switch
- Damage in cables and cords
- Viability of fuses, diodes and resisters
- Conductive ability of an electrical pathway
With a multimeter, you can measure both AC and DC voltage—particularly useful for locating short circuits or determining if a rechargeable battery is holding a charge. Start by selecting the corresponding current on the multimeter and a voltage range higher than the current you’re testing. For example, if you’re measuring the voltage in a 120-volt wall outlet, turn the multimeter knob to the next highest option—200 ACV. If you’re testing a 12-volt car battery, select the next highest option—20 DCV.
Then make sure to connect your test leads to the proper jacks before testing: For voltage testing, plug the red lead in to the port labeled “V.” For this and all multimeter tests, the black lead plugs into the common (COM) port.
To test a battery’s DC charge, touch the red probe to its positive terminal and the black probe to its negative terminal; the multimeter will display the existing charge in the battery. Since polarity isn’t an issue in AC voltage, it doesn’t matter which probe you insert in either hole of a wall outlet; insert both probes, and the multimeter will display the voltage at the outlet.
Safety Tip: Hold probes by their insulated handles. Do not touch the metal part of the probes to avoid electrical shock.
Testing Resistance and Continuity
In electronics, “resistance,” is the amount of hindrance to the flow of electricity, and less is more—or, rather, good for the operation of your appliances. Multimeter in hand, you can test resistance in circuit board components and appliance elements throughout the house. If, for example, a microwave isn’t operating as it should, this checkup could help you you determine if you should replace a single non-functioning component on the circuit board or buy a new microwave outright.
First, make sure the appliance is unplugged before testing. Plug the red lead into the port with the ohm’s symbol, “Ω,” and select the lowest ohms’ function on the dial. While you can test individual capacitors and components directly on a circuit board, you’ll get a more accurate reading if you remove a component and then test it. When you touch the black and red probes to both ends of a component, simultaneously, you’ll get a reading. The lower the reading, the less the resistance to electrical flow. By comparing the readings from other components on the circuit board, you can determine whether or not to replace a component with an unusually high reading.
To test the continuity, or continuous flow, of an electrical path between two points, plug the red lead into the “Ω” jack and turn the dial to the continuity symbol. A small reading—or a beep—indicates there is a continuous path between the two points. No reading or beep, however, indicates a problem. For example, if you’ve just put a new bulb in your lamp but it still doesn’t turn on, running this test at both ends of its power cord can confirm that an internally broken cord is to blame for your dim room.
Testing Low-voltage Current
In order to measure low-voltage current, the multimeter must become part of the circuit, allowing the current to actually run through the multimeter. This is handy for determining whether a low-voltage circuit, such as a looped set of solar-powered landscape lights, is getting power to all the lights. For this test, plug the red lead into the port labeled, “A,” for Amps, and select the next-highest Amps function on the dial.
Your operating manual may provide a chart, but if not, you can test a simple circuit by connecting the live feed from the power-supply (usually black) to the multimeter’s red probe. The multimeter’s black probe then connects to the positive wire (usually black) on the appliance you’re testing. Finally, the neutral power-supply lead (usually white) connects to negative appliance wire (also white). When you’ve hooked up the circuit correctly, turn on the power source to measure the electrical flow rate, or amps, through the circuit.
Safety Tip: As previously mentioned, do not test a circuit that exceeds your multimeter’s capability. Multimeters are “fused” at a maximum amount of voltage, which is typically lower than household current. If a multimeter bears the words, “10A MAX FUSED,” do not test any current you suspect might be higher than 10 Amps.
Digital multimeters are an important part of many professions and hobbies.
If what you’re doing is related to electricity in any way, chances are you’ll use a multimeter at some point. But once you’ve bought a multimeter, how do you make the most of all the features it has to offer?
In this article, we’ll go through the basics of using your multimeter. Chances are your multimeter will be able to do all these basics, but not every multimeter will look the same.
After reading this article (or while), spend some time with your digital multimeter’s manual to find where you can find specific features on your model.
Design of a digital multimeter
Although each model of digital multimeter will look slightly different, they’re all set up the same way.
There is a display at the top where you can read the measurement’s results, there is usually a round dial to select different types of measurements, and there will be some probe connectors (similar to an audio jack you’d hook a pair of headphones up to) that hold the test probes.
To execute most measurements, you’ll need to hook up the test probes to the digital multimeter using the probe connectors.
Not every measurement will use the same combination of probe connectors, so make sure you familiarize yourself with each unique setting.
Basic features of a digital multimeter
Not every digital multimeter will have the same features. Some can measure temperature, perform diode tests, or measure specifics about car engines. If you’re looking to use your digital multimeter for a specific purpose, make sure you buy one that serves that same purpose.
But just as a multimeter’s design has a standard setup, there are some basic features that are present in every multimeter. In short, the three measurements that almost every multimeter will allow you to do, are continuity, voltage, and resistance.
As we mentioned before, there is a chance your specific multimeter differs slightly, but as a general guideline, these will be standard features on your digital multimeter.
Testing continuity with a digital multimeter
Continuity testing is one of the main functions of a digital multimeter, and many people will buy one just for this feature. A good electrical circuit is an uninterrupted line from point A to point B.
Testing continuity means nothing more than testing whether that line is indeed uninterrupted, or if there is a break in a wire or circuit. It can be used to test a switch or a fuse.
Before you test, make sure that there is no current going trough the object you’re testing. Then, put your black probe in your multimeter’s COM port, and the red probe into the port marked VΩmA.
Next, select the continuity setting with the dial on your multimeter. If your model doesn’t have a dedicated continuity setting, select the lowest ‘resistance mode’ setting. This sends a small signal through the test object and sees if it comes through okay.
With the probes in place and the correct setting selected, first push the metal ‘leads’ (the ends of the probes) together. The display should measure close to 0, and if your model has a continuity setting, you’ll probably hear a beep. This means you’re ready to test your object.
To perform the test, place each probe at one end of the object you’re testing. If there are no problems in the object, you’ll again see a value on the display around 0 and you may hear a beep. Test complete!
Testing DC voltage with a digital multimeter
Another common test with a digital multimeter is testing DC voltage. There are two types of voltage (AC and DC), but because this is a beginner’s guide, we’ll stick with DC voltage.
This is the type of voltage that you’ll find in household electronics, anything that runs on batteries, and batteries themselves. AC voltage is the kind of voltage that your house’s electrical circuits are made up of, and therefore much more dangerous (and less suited for a beginner’s guide).
To start the test, place your probes in the same ports as we did with continuity testing; the black (negative) prompt in the common port indicated with COM, and the red (positive) prompt in the VΩmA port.
Select the DC voltage meter function on your multimeter; it is displayed as a V with one straight line and a dotted line right under it. If you have a manual multimeter, you’ll also have to select the voltage range of the object you’re about to measure. For example, if you’re measuring a 1.5V AA battery, you’d select the 2V range.
Next, place one lead on one end of the object, and the other lead on the other end. After a while, the reading should be displayed on the display section of your multimeter. It is not that important which end you use the positive and negative prompts; if the leads are reversed, the reading will display in the negative (but still be the same value).
Testing resistance with a digital multimeter
Our last test is a resistance test. You’d want to carry out a resistance test to analyze the condition of a circuit or object. The higher the resistance, the less of a current flow there is.
Resistance is measured in ‘Ohms’ and is displayed with the Ω symbol on your multimeter’s dial. If you’re not sure about the range, start in the highest setting and work your way down from there.
Testing resistance looks a lot like the other tests. Your probes go in the familiar ports, so black in the common port, and red in the VΩmA port. Once you’re ready, put each of the leads on opposite ends of the test object and wait until the display settles on a number.
In this article, we’ve looked at the basics you’ll find in any digital multimeter. We’ve discussed design, features, and the three main functions of using a digital multimeter.
Most multimeters will offer additional features and functionalities, so make sure you dive into your model’s manual as well to discover all that your digital multimeter has to offer!
The point of checking for continuity with an analog multimeter is to determine whether the circuit you’re testing is closed or open. An open circuit will not function as the electric current is not being channeled properly or it is being stopped by a break in the system. For a light switch or an outlet to work, it has to be on a closed circuit. This means that the current can move from positive and negative to your device, making it run. As an example, an electrical outlet is an open circuit end or plug that becomes closed when you plug a cord into it, as the cord closes the circuit.
Step 1 – Shut Off the Device
Before checking for continuity with your analog multimeter, you will want to shut off or disconnect power to the device to avoid electrical shock or damage to your multimeter. If you’re testing wall outlets and connections, be sure to turn off power to that part of your home or office from the circuit breaker. Be sure to reverse the process once your testing has been completed.
Step 2 – Set Multimeter to the Ohm Setting
Now you will set your analog multimeter to the Ohm setting, represented by the Greek letter omega. On your device you should see a number of other settings as well, these are for other operating frequencies and tests that involve current checks. The Ohm setting is used for sending a small electrical charge through the line to check for a closed or open circuit.
Step 3 – Read the Multimeter
When the analog multimeter is not connected to anything, the needle will read infinity. When the connectors are not connected to anything and read an infinity reading, that means its an open circuit, so it would read this on a circuit that is not closed during a test. When you touch the two ends of your meter together, it then will read 0. This means that the circuit is closed or complete and functioning properly. This means that it will hold an electric current and the device will function properly without loosing its current.
As an example, shutting off electricity to a socket, and then testing the outlet itself, by placing one tip in each opening in the outlet, ignoring the ground hole, you should get a complete circuit or a reading of zero. What is happening is a small charge is sent through the line from positive to negative, where it travels through the wires and back to the meter. If there is a broken wire or lost wired connection in your circuit, the meter will read infinity, which lets you know the circuit is open or broken. If it can not complete the loop, the line will not hold an electrical current and could be an electrical or fire hazard in the example of an electrical outlet.
Fig. 1: Image of an LED circuit on breadboard
Image above shows a simple circuit that glows an LED when connected to power supply.. Connecting LED directly to the power supply will damage it, hence aresistance of suitable value must be connected in series for its proper operation. Following the standard color convention,red wire serves as the positive connection lead while black one is the common or negative lead. In this tutorial, we will be measuring DC voltage and current in the circuit.
How to Measure Voltage using Multimeter
Fig. 2: Image of LEd circuit working on a breadboard
9V DC supply is used to power the circuit. The LED will glow as soon as we connect the wires to the power source. Make sure that all the connections are tight. If the LED doesn’t glow after connecting the supply, then check the connection and the LED.
Fig. 3: Image showing multimeter probes connected to LED circuit for voltage testing
Step 1: Connect the testing leads to the multimeter.
Step 2: Turn the knob to the DV voltage segment in the multimeter at 40DCV.
Step 3: Connect the probes in the circuit according to the polarity.
Fig. 4: Image of multimeter showing DC voltage reading from LED circuit
Step 4: Power on the Multimeter.
Step 5: Note down the reading.
The multimeter will show the voltage across the circuit. For example the voltage across this circuit is 6.84V
How to Measure Current using Multimeter:
Fig. 5: Image showing connection of probes in Multimeter for measuring current
Multimeter has different procedure for measuring current. Current can be measured in the range ofmilliamperes (400mA max.) to Ampere (10A max.) as shown in the above image.
Fig. 6: Image showing multimeter probes connected to LED circuit for measuring current
Multimeter works like an ammeter when ammeter.
Fig. 7: Image showing multimeter set to DCA region
Step1: Turn the knob on the DCA section.
Step2: Choose the current rating. The meter will display current in both rating.
Step3: Connect the testing leads to the current measurement setting.
Step4: Turn ON the multimeter.
Step 5: The multimeter will display the current in the circuit shown as shown in the image below.
Fig. 8: Image of multimeter showing DC current reading from LED circuit
As shown, 0.4 mA of current flows into the ciruit.
If your digital multimeter offers a frequency setting (Hz is the symbol) on the dial:
- Turn the dial to Hz. It usually shares a spot on the dial with at least one other function. Some meters enter the frequency through a secondary function accessed by pushing a button and setting the rotary switch to ac or dc.
- First insert the black test lead into the COM jack.
- Then insert the red lead into the V Ω jack. When finished, remove the leads in reverse order: red first, then black.
- Connect the black test lead first, the red test lead second. When finished, remove the leads in reverse order: red first, then black.
- Read the measurement in the display. The abbreviation Hz should appear to the right of the reading.
If your digital multimeter offers a frequency (Hz) button:
- Turn the dial to ac voltage ( ). If voltage in the circuit is unknown, set the range to highest voltage setting.
Note: Most digital multimeters power up in Autorange mode, automatically selecting the measurement range based on the voltage present.
- First insert the black test lead into the COM jack.
- Then insert the red lead into the V Ω jack.
- Connect the test leads to the circuit. The position of the test leads is arbitrary. When finished, remove the leads in reverse order: red first, then black.
- Read the voltage measurement in the display.
- With the multimeter still connected to the circuit, press the Hz button.
- Read the frequency measurement in the display. The Hz symbol should appear in the display to the right of the measurement.
Frequency measurement overview
Circuits and equipment may be designed to operate at a fixed or variable frequency. They may perform abnormally if operated at a different frequency than specified.
Example: An ac motor designed to operate at 60 Hz operates slower if the frequency is less than 60 Hz, or faster if frequency exceeds 60 Hz. For ac motors, any change in frequency causes a proportional change in motor speed. A five percent reduction in frequency yields a five percent reduction in motor speed.
Some digital multimeters include optional modes related to frequency measurement:
- Frequency Counter mode: It measures the frequency of ac signals. It can be used to measure frequency when troubleshooting electrical and electronic equipment.
- MIN MAX Recording mode: Permits frequency measurements to be recorded over a specific time period. It provides the same function with voltage, current and resistance.
- Autorange mode: Automatically selects the frequency measurement range. If the frequency of the measured voltage is outside of the frequency measurement range, a DMM cannot display an accurate measurement. Refer to the user’s manual for specific frequency measurement ranges
In some circuits, there may be enough distortion on the line to prevent an accurate frequency measurement. Example: ac variable frequency drives (VFDs) can produce frequency distortions.
When testing VFDs, use the low-pass filter setting in the advanced multimeters for accurate readings. For multimeters without the low pass filter setting, turn the dial to dc voltage, then press the Hz button again to measure the frequency on the dc voltage setting. If the meter allows for a decoupled frequency measurement, you might also try changing the voltage range to compensate for the noise.
Also Read: How to Test a Diode
Need to troubleshoot a dead outlet? Purchasing a multimeter, the go-to tool for diagnosing electrical problems, could allow you to investigate and address outlet issues. Not sure how to test an outlet? Read on, and the experts at Mr. Electric® will help you learn how to use a multimeter to test an outlet.
What Can a Multimeter Tell You?
A multimeter can help you determine:
- If power is actually reaching an outlet
- If the outlet is properly grounded
- Whether wiring within the outlet is reversed
How to Test an Outlet with a Multimeter in 8 Simple Steps
- Learn the essentials of outlet testing safety.
Because you will be performing these tests on a live outlet, ensure safety by holding both meter probes in the same hand. This will prevent shock from passing through your body. Never allow the metal portion of the probes to brush each other or touch, as this can create a dangerous short circuit.
- Get to know outlet geography.
Modern outlets have three slots: one for hot, one for neutral, and one for ground. The rounded half circle is the ground, the longer slot (left) is the neutral and the shorter slot (right) is hot. Remember that any of the three wires can carry current, so treat each one with caution.
- Adjust your multimeter.
Set your meter to measure voltage. Select the alternating current (AC) function on the multimeter, which is often depicted with a wavy line. The DC function will have a solid and a dashed line.
- Connect the leads.
Push the short, thick connector (called a ‘banana plug’) of the BLACK lead into the connector labeled ‘COM’ (it may have a minus “-” sign beside it). Then, plug in the RED connector labeled with a “+” or horseshoe symbol (the Greek letter Omega).
- Measure the voltage to determine if the outlet has power.
Using one hand, insert a probe into each vertical slot on the outlet. Red goes in the smaller slot, black into the larger one. A properly functioning outlet will give a reading of 110-120 volts. If there is no reading, either something is wrong with the wiring in the outlet or the circuit breaker is tripped.
- Determine if the outlet is properly grounded.
Keep the red lead in the small slot and move the black lead and place it in the ground (Uu-shaped) outlet slot. The reading should remain the same. If it doesn’t, the outlet is improperly grounded.
- Check if the wiring is reversed.
Place the red lead into the large slot and the black lead into small slot. If you get a reading, the wiring is reversed. This won’t affect simple equipment like lamps but can cause issues for more sophisticated appliances and electronics.
- Determine problems with a particular appliance.
Learn “How to Make Electrical Tests” with the help of Mr. Appliance, a fellow Neighborly® home services company.
Count On Mr. Electric for Safe, Prompt Electrical Service
Need to resolve your outlet issue? Avoid a hair-raising electrical experience. Your local Mr. Electric will be happy to help with any electrical projects you’ve been putting off. Schedule an appointment online or call us at (844) 866-1367. Contact Mr. Electric today.
This blog is made available by Mr. Electric for educational purposes only to give the reader general information and a general understanding on the specific subject above. The blog should not be used as a substitute for a licensed electrical professional in your state or region. Check with city and state laws before performing any household project.
Set the multimeter in DC millivolts and connect the output wires of the load cell to the multimeter. Supply a voltage of 5V or 9V DC at the excitation leads and place a test weight on the load cell. The multimeter will register a change in voltage measured across the load cell’s output.
How to Test a Load Cell
To test a load cell before putting it to use, you’ll need a multimeter and a voltage source. Measure the resistance of the input and output leads of the load cell by setting up the multimeter in Ohms. Compare the measurement values with the calibration certificate from the manufacturer to see if they closely match each other. Similarly, check the load cell for accuracy by measuring the millivolts signal from the input leads. With no force applied to the load cell, the value should be zero. Apply a calibrated dead weight as specified in the calibration certificate and compare the values again.
How to Measure Load Cell Output
Load cell output is measured using a digital meter. The digital meter connects to the output of the load cell. It converts the digital signals produced by the load cell into readable digital values. You can also measure the output of a load cell using a multimeter. However, a multimeter will delete the output voltage in millivolts, and will not convert it into force or weight.
How to Check Load Cell Resistance
A load cell test is performed using a digital multimeter. The digital multimeter is connected between the positive signal wire and the negative signal wire of the load cell. The output between them should be equal or to a value specified in the datasheet. This is the test for load cell output resistance. Now check the signal between the positive excitation wire and the negative excitation wire. They should be equal. This is the test for input resistance.
Load Cell Value Fluctuation
Load cell values can fluctuate due to several reasons. From physical damage such as shock loading and overloading for a longer duration to environmental conditions such as temperature, moisture, water ingress, or corrosion, the load cell is likely to produce erroneous output. Measurement values will also fluctuate if the cables break or if there’s a short circuit. To check what is causing fluctuations in the load cell value, perform a visual check to identify the fault location. Perform a zero balance check to identify if the strain gauge has undergone permanent deformation. An insulation resistance check can further help you identify if moisture is getting inside the load cell. Additionally, a bridge resistance check will determine if there’s a short circuit within the load cell.
Load Cell Zero Drift
Zero drift is the condition where zero measurements of the load cell change randomly under no-load conditions. It can also happen when the apparatus is loaded, and this phenomenon is called Drift. Several reasons such as mechanical errors, fluctuation in excitation voltage, and temperature variations could cause drift. To troubleshoot the load cell for zero drift, it is important to inspect the entire system.
Load Cell Negative Reading
Load cell negative reading occurs when the load cell is in an incorrect orientation. If the load cell is upside down, it would produce negative readings under loading. There is usually an arrow on the load cell that shows the direction of loading. A Load cell used to measure tension will not reflect negative reading if installed upside down and will result in an erroneous reading. However, if the load cell is installed correctly and the readings are still negative, verify the wire connection according to the color code specified by the manufacturer.
Load Cell Overload
Every load cell comes with rated capacity. Loading the load cells beyond the rated value overloads the load cell. The telltale signs of load cell overload are inconsistent display reading, reading not coming back to zero even after the load is removed, the dramatic change of zero balance, etc. Shock overload is one of the most damaging among overloads. Here the weight on the load changes to a significant degree in a very short period. Most load cells endure some overload and this value is called Safe overload. Anything beyond that can lead to permanent damage.