Re: results

From: 	Gary Lau  27-Aug-1997 1517[SMTP:lau-at-hdecad.ENET.dec-dot-com]
Sent: 	Wednesday, August 27, 1997 2:59 PM
To: 	tesla-at-pupman-dot-com
Cc: 	lau-at-hdecad.ENET.dec-dot-com
Subject: 	Re: results

>>I'm using the salt water glass bottle caps, but everytime I go to
>>discharge them before adjusting the coil, they don't spark or anything.
>>I don't get it.

>From:   Mad Coiler[SMTP:tesla_coiler-at-hotmail-dot-com]
>This is because your caps are being applied AC voltage, wich continously
>charges and then reverses polarity. If you applied a dc voltage it might
>stay charged. It also doesn't take much leakage to discharge a small TC
>capacitor. I have never gotten any sparks off my primary capacitors,
>though I ALWAYS try and discharge them. It only takes one screw up, one
>nanosecond, and your toast.

Applying AC does not guarantee that no charge will remain when turned
off.  The reason one doesn't get a spark from the primary tank cap of a
tesla coil is that there is a DC path through the primary coil, chokes
(if any), and HV transformer that will always ensure that the cap is
discharged if power is turned off.  But knowing and believing this, I
still poke it with a screwdriver, just in case.

Note however that this is not true if one uses a series arrangement of
caps to increase their breakdown voltage.  It is possible in this
configuration for a charge to remain on the caps.  If there are just
two caps in series, shorting one will discharge both.  In the unlikely
configuration of 3 or more caps in series, shorting one cap at a time
will NOT discharge the others.

Gary Lau
Waltham, MA