What Is a Bad Capacitor?

23 Nov.,2023

 

In this image I have flipped the cap around in the test clips and read it again. Now it is coming up as a capacitor, and we can see readings related to capacitance too. Let us take a moment to decrypt the readings the meter is displaying now.

Reading across we see; 1-||-3 Vloss=34%

On the next line is shown; 943μF ESR=2.2Ω

1-||-3 are the test points the meter has found a component on

Vloss is the amount of voltage the meter has measured that the capacitor has lost.

943μF is the capacitance the meter has measured of the capacitor. 943 micro Farads.

ESR=2.2Ω is the measured Equivalent Series Resistance (ESR) of the device under test.

Well, you may ask, Why is any of this so bad? To begin with it is a 2,200μF capacitor so 943μF is not even close to its marked capacity. But that is not the worst of it. A voltage loss of 34% is terrible! This part is leaking electricity like a sieve. Which is not what capacitors are supposed to do at all. Quite the opposite in fact. Capacitors are supposed to be able to store electricity. They are supposed to have the capacity to store an electrical charge. Hence their name. The ESR measurement is pretty bad too, but not nearly as out of spec as the Vloss.

There is a lot of talk about ESR, so if you are interested in that I suggest you browse the web for additional information on that topic.