0
\$\begingroup\$

In a traditional power switching supply PCB like this one,

enter image description here

(source of the image)

ceramic capacitors are sometimes present as discrete components. They appear as:

enter image description here

(source of the image)

I would like to correctly identify them, when no schematics is available, to replace them if/when they get damaged. In the case of the above image, these parameters can be obtained:

  • the capacitance 822, which, according to this answer, is: 82*10^2 pF = 8.2 nF;
  • the tolerance Z, which, according to this table, is -20 %, +80%;
  • the voltage rating 1KV, which is 1000 V.

(A letter can occasionally appear above these parameters, and I do not know its significance).

Is any ceramic capacitor, which has these same values, suitable to replace the above one, or other features must be taken into account when replacing such a component?


This question is related to a previous one.

\$\endgroup\$
  • \$\begingroup\$ Very rarely these tpyes of ceramic capacitors are broken. Mostly it is the electrolytic capacitors that have to be replaced. Otherwise it should be sufficient if you consider your given parameters for the ceramic types. \$\endgroup\$ – Tom Kuschel Jan 11 at 18:04
  • \$\begingroup\$ @TomKuschel Unfortunately I've seen these capacitors popped in more than one PCB, maybe due to some unexpected voltage spike in the power line. This is why I'm asking. \$\endgroup\$ – BowPark Jan 11 at 18:12
2
\$\begingroup\$

Is any ceramic capacitor, which has these same values, suitable to replace the above one, or other features must be taken into account when replacing such a component?

Be very careful here. If the capacitor is X or Y rated then swapping it with one that isn’t is asking for trouble. X and Y rated capacitors are specifically designed to fail safe thus, if they are used in filters across live AC terminals or AC to ground, you must replace with the correct type.

The good news is that every single X or Y rated capacitor has markings that are reasonably unambiguous in that respect: -

enter image description here

The ones above are Y rated.

enter image description here

These are X rated.

| improve this answer | |
\$\endgroup\$
  • 1
    \$\begingroup\$ Thanks for clarifying this. I didn't know X- or Y-rated capacitors, but this is exactly the reason why I asked the question. \$\endgroup\$ – BowPark Jan 11 at 18:14

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.