How to Test a Capacitor With a Multimeter?

Do you know how to test a capacitor? Many electricians will come across capacitors in their work, but not all of them understand what testing a capacitor entails. The purpose of this article is to teach you the basics of how to test a capacitor and find out if it needs replacement or repair.

When a capacitor fails, it will often leak electrolytic fluid and lose its ability to store energy. This can cause permanent damage to the device that the capacitor is in. When this happens, you may need to replace the component or have a professional take care of it for you.

If you are an electrician who needs to test a multimeter with a multimeter, this blog post will help.

There are many different types of capacitors and just as many ways to test them. If you have the equipment at your disposal, then testing for ESR is probably the best way. However, if all you have is a DMM or digital multimeter, then that’s ok too!

Capacitor Basics

A capacitor is a type of electrical component that stores energy in an electric charge form. They are used for many different things, but most commonly can be found inside electronic circuits to store and release power on demand. 

A capacitor’s capacity to hold this electric charge will depend mainly upon its physical size and the circuit arrangement at play when it was charged up by passing electricity through it from another part of the electronics infrastructure. 

Once connected into an active circuit with voltage applied across both plates, charges begin flowing between them until one plate cannot handle any more; then, all those stored electrons flow back out onto other parts of the circuitry throughout what’s known as charging & discharging cycles!

Testing a Capacitor Using Ohmmeter of a Multimeter

In this passage, we will see how you can check a capacitor with your multimeter set on the ohmmeter setting. This test is easy and will only take seconds! 

To do this test, place one probe across both leads of the capacitor (either orientation doesn’t matter). Next, put in resistance readings for each lead by reading it from left to right. 

If there are any problems here, then the chances are that our capacitor is wrong or needs some form of maintenance before use, so please be careful when checking capacitors like these because they could potentially damage electric components such as lights over-charging not appropriately checked beforehand.

Testing a Capacitor’s Resistance with an Ohmmeter 

A capacitor is a device that stores energy in an electric field. It protects circuits from voltage spikes and helps stabilize the power supply to sensitive electronics like computers. 

If we read a very low resistance across the capacitors (near 0 ohms), this means there’s some short circuit going on with it- meaning that no electricity can flow through due to one or more defects within it. 

This often happens when you leave your laptop plugged into the charger overnight: as soon as unplugging becomes necessary for whatever reason, even just temporarily offloading any last bits of data before shutting down properly, sometimes what’ll happen is not only will everything go dark instantly but also if enough heat has been generated by long exposure during charging cycles then smoke might start.

Testing a Capacitor with a Multimeter in the Capacitance Setting

Poor capacitance can cause a circuit not to work, and the capacitor must be functioning correctly. All you need for this test is your multimeter set up on its Capacitance setting with two probes touching the leads of an unknown capacitor.

This will likely lead to more positive feedback from customers using their equipment correctly but still having issues once in a while because they’re unaware of how some things should be done when there may be something wrong, such as malfunctioning parts or dirty connections.

You should read a value near the capacitance rating of the capacitor. Due to tolerance and the fact that (specifically, electrolytic capacitors) may dry up, you may read a little less in value than the rated’s capacity. 

This is fine. If it is not too far below or nothing at all lower for your readings? That would mean this has to be replaced like magic!

Checking on one aspect of performance–in this case, how much voltage can pass through it is a good enough way to tell if an old capacitor needs replacement.

Testing a Capacitor with a Voltmeter

There are several ways to tell if your capacitor is suitable or not. One way that’s quick and easy, which you’ve probably already heard before, would be the voltage test.

The anode has one type of charge (positive), while the cathode has another type (negative). You can use this difference in charges as well – for example, with some jumper cables – to generate power by using both halves together!

If you’re wondering if your capacitor is working correctly, just charge it up and check for voltage on the terminals. If there’s a reading that matches what you charged it to, then the capacitor has retained its ability to store power across two terminals. 

However, if no such reading exists or isn’t as high of a voltage level after charging, then before starting this test- something may not be suitable with your cap!

Charging a Capacitor

To charge the capacitor, apply DC voltage to its leads. The polarity is essential for polarized capacitors (electrolytic). 

If you are dealing with a polarized capacitor, then observe polarity and correct lead assignments: positive goes on anode (longer) side of the capacitor; negative or ground should go onto cathode(shorter). Apply a voltage that’s less than it can handle to have time charging up—examples include 9 volts with 25V capacitors.

As long as you’re not using a huge, huge capacitor, then it will charge in just seconds after the charge is finished disconnecting from the voltage source and read its voltage with your multimeter. The first reading should be nearly 9 volts (or whatever) that were fed to it!

If you notice that the voltage rapidly declines and quickly drops to 0V, there is a problem with your capacitor. 

This behavior means that either your cap has already experienced damage or its defective. If this sounds like what’s happening for your electronics to function correctly, be sure to replace the faulty component!

Things To Know

The time taken by a capacitor to discharge about 36.8% of the applied voltage’s peak value can also be measured, and this valuable information is used in our formula for determining what kind of capacitor we need!

Checking your capacitors is simple and easy! They lose their ability to build up power over time, which means it’s best practice for you to check them periodically. 

Our online store has a wide variety of meters that will help with the process, including RLC meters if needed! 

If you have any additional questions or concerns about choosing the test mode or carrying out tests per se, please contact our technical support team. They’ll be more than happy to assist!”

About Blake Sutton

Blake has worked as an electrician for over 10 years, receiving his Journeyman Electrician license in 1998. Looking to take his professional electrical career further, in 2008 he received his Bachelor of Science in Electrical Engineering (BSEE) from the University of Texas in Austin. Blake now works full time as an electrical engineer, specializing in power systems.