Electronic – How to choose between ceramic and electrolytic capacitors


I was designing a circuit, I found a lot of datasheets that don't specify if the capacitor should be ceramic or electrolytic. So I started to wonder if the value of the capacitance would tell me the kind that should be used.

Is it true that when the capacitance is of nF or pF order, ceramic capacitors should be used and when the order is of uF, electrolytic ones should be used?

Best Answer

I would have posted this as a comment if I had enough reputation for that.

As Peter Bennett points out, for capacitances < 1 µF ceramic is usually good while electrolytic is good for the rest. However, because of the higher inductance of large electrolytic capacitors they usually behave quite non-ideally for high frequency signals. To get a around this problem one can use an electrolytic capacitor in parallel with a ceramic capacitor. Then the electrolytic capacitor will provide good behavior for the low frequency part of the signal and the ceramic capacitor will provide good behavior for the high frequency part of the signal.

Example: You need a capacitance of 100 µF. Then, I would use one electrolytic capacitor of 100 µF in parallel with one ceramic capacitor of 1 µF. (That would provide a total capacitance of 101 µF, but capacitiors are usally much less accurate than within 1 % of the specified value anyways.)

Also, my (and Peter Bennets's) answers are only valid when you don't have any specific requirements due to the application you are working with (as user19579 points out in the comments of your question).