[Boatanchors] Caution re: 30 - 100 UF 5KVDC PS Filter Capacitor

[Brad Thompson]

At 06:47 PM 8/10/2008, Greg Mijal wrote:
>Hi:
>I'm looking to buy a 30 to 100 uf capacitor for power supply 
>filtering Max DC working voltage is 5 kv.
>In a single package.  Something along the lines of what has been 
>coming out of Russia recently.
>I'm working on a minimum space 3 kv supply for transmitting.

Hello--

Greg and other hams who have experience with tube circuitry no doubt 
already know about this phenomenon, but in case any newcomers
to the hobby read this thread... here goes.

Due to dielectric absorption, a large, high-voltage capacitor in good 
condition can often regain a surprising (and dangerous) amount of charge
after its removal from service. Manufacturers ship these capacitors 
with a shorting wire connected across their terminals-- be careful handling
any capacitors that aren't so supplied. Consider installing shorting 
wires on any caps in your collection, but carefully discharge them before
installing the wires.

73--

Brad  AA1IP