Re: TOT: Capacitors

The bit that everyone has missed - the voltage rating. It is VITAL that
any electrolytic capacitors are of the same or higher voltage rating
especially for big values or high voltages.

At high voltages the actual capacity does not matter so much. Many
canned types were 32+16uF or 16+16uF at 450V. If you cannot get a
32+16uF then fit a 16+16uF - it will make little or no difference.

At lower voltages if you are looking at 3300uF 50V and all you can get
is 4700uF 63V or 100V, if it will mechanically fit then use it. In
semiconductor equipment dropping below the capacitance value might cause
hum or - in the case of an amp - result in early onset clipping at high
volumes. If the old unit has a surge current rating printed on the case,
make sure the replacement has similar or better rating.

Modern capacitors are significantly physically smaller than those of
even 20 or even 10 years ago, so don't be surprised if your replacements
present you with mounting problems. Most importantly if you are
replacing signal capacitors that are small electrolytics do your best to
get comparable types - specifically try to avoid replacing electrolytic
with tantalum. If you cannot get the exact value go for the next value
higher both in capacity and voltage.


--
Woody

harrogate three at ntlworld dot com


.

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