No argument, Norm, although if I remember right the '5404 is rated for 400A
surge for a longer time than a typical HV filter cap takes to discharge
through a 20-50 ohm suppression resistor (~100A peak, decreasing on an RC
decay curve of roughly 1 ms time constant (50 ohms x 20 uF, etc.).
73, Dick
-----Original Message-----
From: notawc@juno.com [SMTP:notawc@juno.com]
Sent: Thursday, May 13, 1999 2:59 PM
To: amps@contesting.com
Subject: Re: [AMPS] Henry 2K2; glitch resistor in negative HV
considerations
On Wed, 12 May 1999 08:45:37 -0600 "Richard W. Ehrhorn"
<w4eto@rainbow.rmii.com> writes:
SNIP
> With grounded-grid triodes we almost always apply positive bias to
> the
> cathode(s). A cheap, husky 1N5404 or similar diode, connected with
> its
> cathode to the cathode end of the resistor and its anode to ground,
> does
> the job of routing fault current to ground (and protecting cathodes
> & bias
> supplies) quite nicely.
IMO you want a diode that can handle the discharge current thru the
resistor and still survive.
Look at the Ameritron big amps and they all use a wimpy 1N4000 series
which goes up in smoke at the first opportunity.
A 1N54xx series is going in the right direction but I would suggest the
next step up, a 6A10 may be a better choice. Remember, we want to be
able to absorb a problem until the primary fuse/breaker or HV fuse
reacts, not have it blow something in the protection chain.
Cheers...Norm
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