Can you use a lower rated capacitor?

Can you use a lower rated capacitor?

You absolutely should not replace an electrolytic capacitor with one of lower voltage rating. That would only be okay if the system was designed with a lot of overhead, but for high-volume devices like PC power supplies that’s very unlikely.

What voltage rating should my capacitor be?

The voltage on a capacitor is not the rating, but rather how much voltage you can expose the capacitor to. For example, if your voltage source is 9 volts, you should choose a capacitor that is at least double the voltage, 18 volts or even 27 volts to be safe.

Is it safe to replace a capacitor with a higher voltage?

Replacing a capacitor with something that has a higher voltage rating is always safe. The only problem there is that a capacitor rated for a higher voltage is often physically larger, everything else being equal.

Which is more effective a 20v or 6V capacitor?

Depending on the dielectric, ceramic capacitors derate based on the DC voltage applied. The higher the voltage rating compared to the applied DC voltage, the less they derate. So you will have more effective capacitance with the 20V rated part than the 6.3V rated part. This does not apply to (polymer) tantalums, film caps, or electrolytics.

What is the voltage rating of a capacitor?

The voltage rating is the working voltage for the capacitor to reach 60,000 applied hours. If the heating or air conditioning unit increases voltage to the capacitor (for example: the capacitor is rated for 370 Vac, and is seeing 440 Vac from the unit), then the life of the capacitor will be lowered significantly.

What kind of derated capacitor should I use?

Aluminum electrolytic capacitors will be derated to at least 50% if the capacitance is critical. Meaning, I will use a 25V cap on a 12.5V rail. If the capacitance is not critical then I will allow for less voltage margin.