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Unknown capacitor

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kostya:
What do you mean by voltage of a capacitor? The voltage difference between the terminals? Isn't that just going to be whatever voltage power source it was charged off of?

GoGeTa006:

--- Quote from: kostya on October 01, 2009, 09:05:50 PM ---What do you mean by voltage of a capacitor? The voltage difference between the terminals? Isn't that just going to be whatever voltage power source it was charged off of?

--- End quote ---

yes but no. . .
if you hook it up to a 9v battery it will have 9 volts. . .
but if you hook it up to a voltage multiplier . . .thats a different story, the capacitors have a voltage limit.

say grab a disposable camera, break it appart you have a 200 uf 300V capacitor. . .you charge 300 volts out of a 1.5v battery. . .

boxer4:
Just sticking in my 2 cents here, even though it's already been covered.

No, without destructively testing a capacitor, you can't tell the WVDC (working voltage DC) or max surge voltage of a capacitor.  You must refer to numbers printed on it.

However usually you can make a good guess.  Provided that your measurements are correct (4cm diameter, 10cm long, 1000uF), that the capactor is in good shape, and a 1990s capacitor, I'd say this is somewhere around 50 to 100 WVDC -- but this is from experience.  However, this could be totally wrong as there's no way for me to tell how the capacitor was made.  Also "good shape" as it's not dried up or anything, this will reduce capacitance leading to an incorrect guess to its WVDC.

And bah, 4cm dia 10cm long... that's tiny...

(and I think my 0.3F ~10cm dia 15cm tall capacitor is actually small compared to the industrial gallon paintcan sized and even larger for motor starting and power factor correction capacitors.)

GoGeTa006:

--- Quote from: boxer4 on October 12, 2009, 06:20:50 PM ---Just sticking in my 2 cents here, even though it's already been covered.

No, without destructively testing a capacitor, you can't tell the WVDC (working voltage DC) or max surge voltage of a capacitor.  You must refer to numbers printed on it.

However usually you can make a good guess.  Provided that your measurements are correct (4cm diameter, 10cm long, 1000uF), that the capactor is in good shape, and a 1990s capacitor, I'd say this is somewhere around 50 to 100 WVDC -- but this is from experience.  However, this could be totally wrong as there's no way for me to tell how the capacitor was made.  Also "good shape" as it's not dried up or anything, this will reduce capacitance leading to an incorrect guess to its WVDC.

And bah, 4cm dia 10cm long... that's tiny...

(and I think my 0.3F ~10cm dia 15cm tall capacitor is actually small compared to the industrial gallon paintcan sized and even larger for motor starting and power factor correction capacitors.)

--- End quote ---

thats small. . .
I really tought it should be well over 300v since its used for a flash.. . .or maybe i got you wrong and WVDC is something idfferent?
well i got my small capacitors that i took out of a flash disposable camera, 300v around 100-200uf

sdedalus83:
I'm so used to dealing with solid state audio electronics that a 4cm x 10cm 1000uF capacitor soundsfreaking huge.

Checking panasonic's electrolytics catalog came up with a 4cm x 8cm 450V 1000uF cap.  Considering the one you have is probably a lot lower quality than the panasonic, I wouldn't be surprised if it's rated for 750V or more for it to be that big.  A camera flash is going to have extremely high voltage requirements with almost no current draw, so that sounds about right.

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