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I Have An Electronics Pcb Project And I Have Problem With The Capacitors…?

I have some ceramic capacitors and some electrolytic capacitors. I want to ask whether i can use the electrolytics with the DC voltage. I will feed my circuit with 6, 12, -12v and I want to ask if the polarity of the electrolytics change, will the capacitors burn or go out? If you can help me, I will be very happy…
Thanks…

6 Responses to “I Have An Electronics Pcb Project And I Have Problem With The Capacitors…?”

1. Jim C Says:
   July 10th, 2009 at 3:12 am

   You cannot run polarized electrolytics backwards, without destroying them. You can find dozens of different non-polarized types on-line from parts distributors such as Mouser, Allied, and Digi-Key. But if you want to get around the problem, there’s still another way; Place two standard polarized electrolytics in series, “back-to-back” so that their negative terminals are connected to each other. Then, place a rectifier diode, such as a 1N4002, in parallel with each capacitor, so that the cathodes are in contact with the positive capacitor terminals, and the anodes are in contact with the negative capacitor terminals. What you will have now made is a “bipolar” or “non-polarized” capacitor that is roughly equivalent in value to one of the two original polarized capacitors! If, for example, both of the electrolytics were rated at, say 2200 MFD @ 25 VDC, the new “homebrew” NP capacitor will function as a 2000 MFD, 25VAC capacitor! Reversing polarity on this “home brew” capacitor will not cause any problems, whatsoever!

2. dmb06851 Says:
   July 10th, 2009 at 10:05 am

   Electrolytic capacitors MUST be connected the correct way round.
   If they are connected in reverse they will almost certainly fail and can lead to damage in the power supply or other parts of the circuit.
   If you need a high value capacitor in a position where it might get biased both ways it is possible to buy non-polarised electrolytic capacitors. They are used in loudspeaker cross-overs.

3. asimovll Says:
   July 10th, 2009 at 1:11 pm

   yup..reverse electrolytic will cause leakage current. It will burn or explode.
   The can is the negative side.

4. ​ Says:
   July 10th, 2009 at 5:07 pm

   Small, capacitors might, but not average-size capacitors, neither will large-sized capacitors.
   P.S. I recommend that you connect a diode on each capacitor to keep the polarity the same all the time (Unless they are non-polorized).

5. Jack Kerouac Says:
   July 10th, 2009 at 9:07 pm

   not only will they burn or go out they could very well explode…NEVER reverse the polarity on an electrolytic cap.
   also if this tantalum electrolytic—its electrolyte can be h2so4 (sulfuric acid)…you dont wnat to have that spewing everywhere…so be advised dont ever reverse the polarized cap

6. Λиδѓεy™ Says:
   July 11th, 2009 at 1:09 am

   As an electic engineer student I can tell you that you should respect polarity, otherwise it woun’t work properly because it wount charge as it should resulting in a burn out

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