Help needed for Capacitors

[kingoftaurus]

So, I have a dilemma.

Minor, but still there.

I have a set of ceramic capacitors with ONLY their capacitance value marked.

IE 104 103 102 101

Ive noticed, that, say I have a 104. Its capacitance is 100nF and its VOLTAGE is 50v.

I see that the 101 the 100pF cap its VOLTAGE is 100v

These capacitors are exactly the same size (compared to others on digikey)

my problem is that these are the only ceramics that I have.

I need to come up with:

.05uF and 500V

im assuming that 2 104 in series will give .05uF but the voltage would be 200v right?

[Richard Head]

The voltage rating will double when connecting equal values in series.

[kingoftaurus]

The voltage rating will double when connecting equal values in series.

So for temporary usage, I would need 5 100v caps in series ?? lol ok..

[Richard Head]

Yes

[KJDS]

NO

The voltage across the caps will not be shared equally. Imagine one has a leakage resistance of 1Gohm and another has a leakage resistance of 10Gohm.

That would leave 90% of the voltage across the one with the higher resistance. The usual solution to this is either to buy the right capacitor and when that is not possible put a resistor in parallel with each capacitor. Just make sure that the resistor can cope with the power and that you still have some margin on voltage too.

[Richard Head]

Assuming the leakage currents are equal that is. If the leakage currents differ by an order of magnitude then all bets are off, but with film caps of the same type the leakage currents are very likely going to be similar. But technically KJDS is correct.

[KJDS]

Assuming the leakage currents are equal that is. If the leakage currents differ by an order of magnitude then all bets are off, but with film caps of the same type the leakage currents are very likely going to be similar. But technically KJDS is correct.

I'm practically correct too, it only takes a fingerprint to make that sort of difference.

[kingoftaurus]

Alright, So I'll just wait. I cant imagine why I need one rated for 500V. Stupid old thing. lol. At least there isn't very many caps in it. (old old oscilloscope from a different thread)