I'm just a hobbyist and I'm planning to build this circuit. It recommends to use a 33pF 63V capacitor. I'm in trouble to find a capacitor with this specific voltage. I only found a 33pF 50V one.

Since the power supply will be 20V, a lower voltage capacitor should not be a problem, right? What kind of problem I will have if I use a 33pF 50V instead of a 63V?

Searching the forum, I found this question, but it has two answers and each one points to one direction...


You are correct. Generally speaking, capacitors must not be subjected to voltages higher than what they are specified for. In practice, one always chooses a capacitor with voltage rating somewhat in excess of the highest voltage the capacitor might be exposed to. For example, I would choose a 63V capacitor for a circuit running at 45V.

Your circuit is running at plus minus 20V. A capacitor voltage rating of 25V is marginal, so I would choose a capacitor voltage rating at 35V or more. Your 50V capacitor will be just fine.

  • 3
    \$\begingroup\$ Also check the manufacturers derating figures as the voltage withstand decreases with temperature \$\endgroup\$ – JonRB Feb 7 '15 at 20:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.