[Top] [All Lists]

Re: [Amps] Modern Op-Amp shunt stabilizator power supply (for tetrodescr

To: jeff millar <>, Steve Thompson <>
Subject: Re: [Amps] Modern Op-Amp shunt stabilizator power supply (for tetrodescr
From: buzzmiklos <>
Date: Mon, 07 Mar 2022 13:41:02 -0500
List-post: <>
8v&5_Sent via the Samsung Galaxy S10e, an AT&T 5G Evolution capable smartphone
-------- Original message --------From: jeff millar <> Date: 
3/3/22  10:15 AM  (GMT-05:00) To: Steve Thompson <> Cc: 
Amplifier Mailing List <> Subject: Re: [Amps] Modern Op-Amp 
shunt stabilizator power supply (for tetrodescr Consider the arc as a zero ohm 
resistor.  The current peak is limited bythe glitch resistor and the impedance 
of the HV capsjeff, wa1hcoOn Thu, Mar 3, 2022 at 8:35 AM Steve Thompson 
<> wrote:> A while ago I breadboarded a screen regulator 
supply with some> similarities to Jim's design. One of these was that the 'pull 
down'> transistor could act as a clamp if there was a flashover to the 
screen.>> I was fortunate enough not to test that function but I had a couple 
of> questions which I never found answers for:>> How much current flows during 
a flashover to the screen (assuming the> amp has a sensible glitch resistor in 
the HV supply) and>> How long does a flashover last?>> Worst case guesses are 
simple enough but I don't know how the physics> of the arc affects things in 
practice.>> Steve G8GSQ>> On Mon, 28 Feb 2022, 21:37 Jim Garland, 
<> wrote:>> > Attached is the screen voltage regulator I 
designed for my 160m/80m> > duo-band amplifier using three GU74B tetrodes. From 
your msg, I suspect> > it’s similar in some ways to the circuit you’ve 
described. The circuitry> is> > deceptively subtle, however, in that it 
provides protection against> damage> > from grid-plate flashovers in the tubes, 
which can be a problem,> especially> > with new (NOS) Russian tetrodes. I’ve 
used this circuit for more than> five> > years and found it to be always 
stable, with tight regulation. The> > circuitry mounts on a small file 
card-sized PCB. The screen voltage is> > adjustable and I set it at a nominal 
340V.> >> >> >> > If the attachment doesn’t come through (I’m away from my home 
QTH and> have> > limited internet coverage, here’s a link to the complete 
schematic> package> > for the amplifier. Pse email me if you can’t get any of 
the diagrams to> > load!> >> >> >> >>> >> 
> 73,> >> > Jim W8ZR> _______________________________________________> Amps 
mailing list>>>_______________________________________________Amps
Amps mailing list
<Prev in Thread] Current Thread [Next in Thread>