0
\$\begingroup\$

Surface resistor has numbers on it to decide whether it's good or bad after measuring it with DMM.

But when I looked at surface capacitors, they don't have numbers or strips to decide their validity and to replace them with new ones with the same values (In case they're bad). So how to find out surface capacitors values (Voltage - Farad)?

Thank you in advance.

\$\endgroup\$
2
  • \$\begingroup\$ Did you mean to tag as electrolytic? They usually have values printed on. \$\endgroup\$
    – Colin
    Commented Apr 23, 2020 at 8:52
  • \$\begingroup\$ @Colin Ceramic Capacitors (SMD Capacitors). I watched many videos and what I found that they don't have values printed on them, and the trick to find out their values is based on their location on the board. The ones near the power source are about 1uF and for the one in parallel, well, you take off one of the good ones to check its value, which would be the same as the bad one. \$\endgroup\$ Commented Apr 29, 2020 at 11:56

1 Answer 1

3
\$\begingroup\$

Surface resistor has numbers on it to decide whether it's good or bad after measuring it with DMM.

No, I mean, yes, you can determine whether a resistor still matches its specified value with a multimeter, but that's not really the reason they're printed on there:

That is device markings, mainly useful for these who need to feed these resistors into placement machines (or even for those who place them by hand).

But when I looked at surface capacitors, they don't have numbers or strips to decide their validity and to replace them with new ones with the same values (In case they're bad).

It doesn't even work like that for resistors! You (in almost all cases) have to remove a component from the board to measure it – otherwise you'd measure e.g. the resistance across the resistor, and everything around it, and that will be wildly inaccurate. So, to measure, you'd first unsolder.

If you've unsoldered your component, you can as well replace it with an identical one that's new. Especially for SMD capacitors, that might be very desirable – measuring small capacitances is pretty hard, anyway.

So how to find out surface capacitors values (Voltage - Farad)?

If there's no explicit markings printed on them: not at all. You'd take a look at what they might be used for (e.g. decoupling on a microcontroller), and then take an educated guess.

\$\endgroup\$
4
  • 2
    \$\begingroup\$ No, I mean, yes = +1 \$\endgroup\$
    – Andy aka
    Commented Apr 23, 2020 at 9:56
  • \$\begingroup\$ Thank you Marcus for such detailed answer, really appreciated. \$\endgroup\$ Commented Apr 24, 2020 at 4:19
  • \$\begingroup\$ Hello Marcus. How to check if SMD Capacitor is faulty without removing it from the circuit? What kind of tests I should run using DMM? \$\endgroup\$ Commented Apr 29, 2020 at 10:15
  • \$\begingroup\$ as I said, you can't. You need to remove it. \$\endgroup\$ Commented Apr 29, 2020 at 13:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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