How to measure a capacitor with a multimeter
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- เผยแพร่เมื่อ 14 พ.ย. 2023
- How to measure a capacitor "on a circuit board" without removing it with a standard multimeter or with a capacitance meter.
The intent of this video is to help a non-technical person to quickly identify a bad capacitor in a circuit without having to own very specialized electronic test equipment. And then show them how easily they themselves can replace it.
Electrolytic Capacitors are many times the reason why a “consumer electronics product” just stops working.
Electrolytic Capacitors are (cheaply made) and are very common in consumer electronics products and can become weak or just go bad with passing of time.
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Thks ?Does this work the same for inductors too?
No. Inductors will aways measure very low resistance/impedance in and out of the circuit. You will need an LCR meter to read the inductance of an inductor. Inductors seldom fail in a good circuit design and when they do you will usually see it. Electrolytic caps can dry out inside and can lose there capacitance over time.
@@gse244 Thks buts another dumb question;
When the volt meter probes are placed across an inductor, ?is there an initial voltage reading that slowly fades-away as the inductor mag-field charges-up (ex: opposite of a cap)?
While this method is good as an indicator, a lot of these caps will still show correct capacitance but in reality the ESR will be too high and therefore bad. Even a cheap ESR meter will tell you this :)
The intent of this video is to help a non-technical person to quickly identify a bad capacitor in a circuit without having to own very specialized electronic test equipment. And then show them how easily they themselves can replace it.
Electrolytic Capacitors are many times the reason why a “consumer electronics product” just stops working.
Electrolytic Capacitors are (cheaply made) and are very common in consumer electronics products and can become weak or just go bad with passing of time.
In many, many things electrolytic caps aren't subjected to enough ripple current for ESR to be a critical factor. It certainly does come into play, but the most common failure in lots of cases is simply "drying out" - loss of the solvent from the electrolyte. This does make the ESR dramatically higher but it also causes the capacitance to drop dramatically.
When you get into things like high frequency switchmode converters ESR is very important and it may reach an unacceptable level without much change in capacitance.
I've designed lots of industrial switchmode power supplies. I've replaced lots of bad caps on things like PC motherboards. I've *never* used an ESR meter as a diagnostic aid.