RE: AC resonance circuit with DC electrolytic capacitors?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "S&JY" <youngs@xxxxxxxxx>

Yes you can, by putting a diode in parallel with each of two electrolytics,
to prevent charging them with the wrong polarity, and then connecting the
caps in series, connecting plus to plus or minus to minus.  BUT it would
only be useful in low power low frequency (audio) resonant circuits.  Higher
frequencies and/or higher AC currents through them will cause dangerous
heating of the dielectric "paste" which, will cause them to leak, making a
mess, or at higher currents, explode.

Also, at RF frequencies, their impedance rises, requiring bypassing the
electrolytic with a ceramic or PP cap, so you might as well just leave out
the electrolytic caps.

Their main use is for filtering DC, or level shifting low power signals.

But just for fun, you can connect two diode protected electrolytic caps
(rated for 250 volt or more) in series with an inductor (e.g. a transformer
winding) and a low power incandescent light bulb (e.g. 10 watt), and connect
this to your AC outlet.  If your LC circuit resonates very close to 60 Hz,
the light bulb, being a non-linear resistor, will cause the circuit to go in
and out of resonance, and the bulb will blink on and off indefinitely.  Just
be sure the caps don't get too warm.

--Steve Y.


-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Tuesday, March 06, 2007 11:21 PM
To: tesla@xxxxxxxxxx
Subject: AC resonance circuit with DC electrolytic capacitors?

Original poster: "alfred erpel" <alfred@xxxxxxxxx>


Howdy all,


         I fully realize I am posing this issue from a standpoint of
incomplete knowledge (ignorance?).
         I was wondering if a circuit could be devised with clever
usage of diodes, etc. which would allow the usage of two electrolytic
capacitors to create a resonant circuit with and inductor(s?) such
that the electrolytic capacitors would only be charged in the
direction which they were designed for.
         If not, an explanation why this wouldn't work would be
appreciated.  Thank you.


Regards,

Al Erpel, 18901, PA, USA




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