Test Capacitor using Multimeter

Test Capacitor using Multimeter

Test a Capacitor with an Ohmmeter of a Multimeter   A very good test you can do is to check a capacitor with your multimeter set on th... 00:22:00

Test a Capacitor with an Ohmmeter of a Multimeter  

A very good test you can do is to check a capacitor with your multimeter set on the ohmmeter setting. By taking the capacitor's resistance, we can determine whether the capacitor is good or bad. To do this test, We take the ohmmeter and place the probes across the leads of the capacitor. The orientation doesn't matter, because resistance isn't polarized.  If we read a very low resistance (near 0Ω) across the capacitor, we know the capacitor is defective. It is reading as if there is a short across it. If we read a very high resistance across the capacitor (several MΩ), this is a sign that the capacitor likely is defective as well. It is reading as if there is an open across the capacitor. A normal capacitor would have a resistance reading up somewhere in between these 2 extremes, say, anywhere in the tens of thousands or hundreds of thousand of ohms. But not 0Ω or several MΩ. This is a simple but effective method for finding out if a capacitor is defective or not. 

Test a Capacitor with a Multimeter in the Capacitance Setting  

Another check you can do is check the capacitance of the capacitor with a multimeter, if you have a capacitance meter on your multimeter. All you have to do is read the capacitance that is on the exterior of the capacitor and take the multimeter probes and place them on the leads of the capacitor. Polarity doesn't matter. This is the same as the how the setup is for the first illustration, only now the multimeter is set to the capacitance setting. 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 capacitance of the rating. This is fine. If it is a little lower, it is still a good capacitor. However, if you read a significantly lower capacitance or none at all, this is a sure sign that the capacitor is defective and needs to be replaced. Checking the capacitance of a capacitor is a great test for determining whether a capacitor is good or not.  

Test a Capacitor with a Voltmeter  

Another test you can do to check if a capacitor is good or not is a voltage test. Afterall, capacitors are storage devices. They store a potential difference of charges across their plate, which are voltages. The anode has a positive voltage and the cathode has a negative voltage. A test that you can do is to see if a capacitor is working as normal is to charge it up with a voltage and then read the voltage across the terminals. If it reads the voltage that you charged it to, then the capacitor is doing its job and can retain voltage across its terminals. If it is not charging up and reading voltage, this is a sign the capacitor is defective.