开云体育

Geo,

I want to return to your question one more time and ask about your predicate....... Does the GM tube really go to ground? I agree that the transient current does go to ground, but when I was trying to figure out how to model a GM tube in a simulation, while designing those silicon retrofit circuits I posted, I came to the conclusion that the unloaded pulse output is on the order of -2+V in the 6993 tube used in the Vic/Lionel, et al.

What comes through the coupling cap to the one-shot input resistance (~9K in the Lionel) is of course attenuated.

Do you agree with that?

rogerw

Q: what happens when the GM tube fires, essentially going to ground?

Geo

---

From: "Roger Whatley" <rogwhat53@...>
To: "CDV700CLUB" <[email protected]>
Sent: Sunday, April 3, 2022 7:40:32 AM
Subject: Re: [CDV700CLUB] Question and an interesting site for those that modify CDV700s and more.

Peter,

The reason I ask is that this Shunt Regulator can be turned quite easily into a Series Pass Regulator such that the "dropping resistor" can become, say 10Meg and the bias currents to the regulator remain small while the load gets only whatever current it demands.

Interested?

rogerw

On 4/3/2022 12:40 AM, peter via groups.io wrote:

Roger:
?PMT resistor divider resistance is all over the place. The lowest I encountered was a commercially made socket for Hamamatsu R647 pmt, and its total resistance was about 3.3 M ohms.The pmt base is tiny and the resistors are inside the potted pmt socket, so no chance in modifying it.?

Many surplus 1 x 1x 3" NaI probes made by Bicron/Alpha Spectra are around 13M ohms. My home made resistor dividers are around 50M ohms~ 240M ohms.?
Many pmts are 8 or 10 stages so 9 or 11 resistors, often all the same value. I often choose 4.7M, 10M or 22M ohm resistors for each resistor.

P

-- 
rogerw
On the Catclaw
ΜΟΛΩΝ ΛΑΒΕ

The PanDemic is over, but the DemPanic goes on.
MisDisMal is a dictator's tool of repression.

Virus-free.

-- 
rogerw
On the Catclaw
ΜΟΛΩΝ ΛΑΒΕ

The PanDemic is over, but the DemPanic goes on.
MisDisMal is a dictator's tool of repression.