[Towertalk] Tailtwister won't turn.

W0UN--John Brosnahan shr@ricc.net
Mon, 05 Aug 2002 17:36:48 -0500


At 03:13 PM 8/5/2002 -0700, Mark wrote:


>Why?  Does not matter, but the practice is fine! I do things by habit,
>too.... It is AC .. does NOT matter.. pluskies or minusers...just back to
>back.. did it for years in speaker crossovers as well as motor starting
>capacitors .. as we are discussing and reading about here.  Mark  6dx

We are talking POLARIZED electrolytic caps here--it  DOES matter.
You can get away with it (sorta) with audio because the voltages
typically are not that great--but they really need to be back to back
and ideally with diodes across them to eliminate the reverse voltage
in motor-starting applications.

The real question is whether you need to divide the effective capacitance
by two.  The caps are really NOT in series in the classical sense--but rather
one cap handles the half cycle voltage of one polarity with the capacitance
with which it is marked.   Then the other cap handles the other polarity
half-cycle with its capacitance.  So it seems to me that maybe the
effective value does not need to be halved.

--John   W0UN