How to test A/C voltage with a Multimeter

A multimeter is a convenient device used to measure voltage, electricity, resistance, etc. It is a tool most households should have, and most handypersons do have. It makes repairs and other jobs more accessible. For example, you can use a multimeter to measure A/C voltage. We have provided you with some helpful information regarding the A/C voltage check.

How to test A/C Voltage with a Multimeter

Before starting A/C Voltage Check:


Before starting your measuring procedure, you should check all the necessary parts used for voltage measurement. Firstly check the multimeter thoroughly. If it is ok, then check its leads properly. If it is also helpful in condition, then you can start your job. Next, we should check the point manually. Check that is it damp or has any damage on it. Check that there is any crack, burned part, internally disconnected or loosens part on it. If all things are fine enough, then you can carry on.

  1. The first step is to switch off all the circuits and plug points.
  2. Sometimes unwanted accidents will occur due to circuit breakers.
  3. Different voltages are also an essential factor behind it.
  4. Then turn on the multimeter, set the energy at the highest range, and dial the correct position.
  5. Insert the black colour probe lead into the COM opening on the multimeter.
  6. Then insert the red colour positive lead probe into the opening that is marked as V sign. Sometimes it could be characterized as the Greek symbol Ω (omega).
  7. It would be best to keep in mind that most of the multimeters are usually in automatic mode.
  8. But when you measure the ac voltage, then you should change an auto mode In custom mode. You should set the meter in the manual setting. Select the Ac volt range for necessary accuracy. So, for example, calculating 12 volts on the 20-volt range will provide additional decimal places than on the 200-volt series.

Multimeter for beginners

  1. Using a multimeter is easier if you have at least some information on it and how it works.
  2. The main parts of this device are the display, the dial, and the ports, probes or leads.
  3. The display will naturally display the measurements you require in digits.
  4. The result will usually consist of four numbers. When something goes wrong, the screen will often show a negative result.
  5. Depending on the model you purchase, the display could have an option of remaining light even in the dark.
  6. The dial or the selection knob is used to set it for particular readings.
  7. For example, in some cases, you will want to measure voltage and in others resistance. Either way, this is what the dial is used for.
  8. The ports are used to connect to devices or systems. Usually, all multimeters will have two probes – a red one and a black one.

Manually test the Leads status

The essential thing is to examine the state of the lead. You verify it by setting the multimeter into its resistance mode. The reading value should be in ohms. After that, you will attach the ports with a tool and touch the tips of the leads. If everything is right, the reading value should be 0.5 ohms or less than that. This test is essential before the primary process. It should do it to avoid massive accidents and injuries.

 Measuring A/C voltage with a Multimeter

First off, you’ll need to know what range of voltage you are dealing with. If you do not know that, then set the range on your multimeter to the highest voltage and turn the dial to ṽ. Make sure your multimeter is not on the auto-range mode. That will not help you get accurate measurements.

Next, you’ll need to connect the black lead with the jack “COM.” Then it would be best if you connected the red lead. It will go in the VΩ jack. Remember to disconnect the red first and the black second when you wish to remove the points leads. Try not to touch the tips of the leads with your fingers.

The next step is to read what you have observed in your multimeter on display. The display should give you the results quickly. If you want to note a measurement without writing it down, immediately press the Hold button. You will know if the reading is completed because there will be a beeping sound.

Not sure which multimeter is perfect for your A/C? Check out our top picks explicitly used for HVAC systems here.

All A/C voltage measurements will inevitably vary. It will depend on how the power is distributed, or in other words, the source of voltage. It can also depend on the type of A/C system. You need to consider that if you measure the A/C voltage at different times, the result will also vary.

Usually, what happens is that the voltage is lower than what we expected or regarded as a standard.

Frequently Asked Questions:

Which is better, A/C or D/C?

Alternating current is more affordable to generate and has fewer energy troubles than direct current when sending electricity over long distances. Although for very long distances (more than 1000 km), direct current can usually be better.

How can you tell if a signal is A/C or D/C?

One way to conclude if you have an A/C-D/C power supply or a D/C-D/C model is to look at the equipment itself. Often, companies write the input and output information somewhere on the surface. So, for example, if the input is A/C, you have an A/C-D/C power supply, and you have a D/C-D/C model if the input and output both are D/C.


At the end of this discussion, I want to say that measuring ac voltage with a multimeter is not difficult for anyone. Everyone will measure this with some proper knowledge of it. But the main key point is to gather a proper understanding of the multimeter. How it works and what type of facilities should be included with it. If you are enthusiastic enough about doing your electrical works by yourself, then select a high-quality multimeter for your daily life use. I hope this article will help you to measure ac voltage by your multimeter. Be careful about the precautions tasks before doing this task at home.

For more information about multimeters, you can read my previous articles on multimeters. I hope you will find this article helpful.

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