>> I have sometimes wondered about the use of polarized capacitors in
>> places
>> where they are just used to couple an AC signal to another circuit.
>> Since
>> the signal being coupled is AC, there really wouldn't be a whole lot of
>> DC potential across it for any length of time.
>>
>> In this case, would it really matter what direction the capacitor's
>> polarity was facing?

> If I drive off a cliff, does it matter if the defroster is on?

Ah, the "what is the sound of one dog barking" answer :-)
Fun but largely meaningless due to its obfuscation value.
Makes the writer feel good but may not inform the questioner.

Olin is *probably* suggesting that the practice is a terminally fatal one 
because it will damage the capacitor.
It is indeed extremely bad practice, but in a truly non DC circuit it MAY 
well work indefinitely with low levels of AC - eg "signal level". Too high 
an AC value will damage the capacitor noticeably on reverse voltage peaks.

If there is ANY DC present whatsoever, align the cap appropriately.
If at all possible, try not to us a polarised cap in an AC only application.
Realise that it is always bad practice to do so and that YMMV*.




        Russell McMahon


* abbreviation to make me feel good but with possibly low recipient content 
;-)



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