Author Topic: GM tube hv transformer  (Read 846 times)

Offline AlexanderHun

  • High Voltage Enthusiast
  • *
  • Posts: 35
  • Karma: +0/-0
    • View Profile
GM tube hv transformer
« on: January 24, 2020, 06:24:25 PM »
Hello!

I managed to get two pieces of Geiger Müller tubes, museum pieces, unfortunately they are operating at a high enough voltage. I need a switch with adjustable output voltage of 1200-1500 volts to test them. Anyone have any ideas?








Offline haversin

  • High Voltage Enthusiast
  • *
  • Posts: 25
  • Karma: +0/-0
    • View Profile
Re: GM tube hv transformer
« Reply #1 on: January 24, 2020, 10:29:14 PM »
I use three parts from a microwave oven  (The Hv transformer, Hv diode and Hv capacitor) and power it with a variac to control the voltage. Most DMM's can measure the output voltage directly. Don't forget a 10 meg anode resistor (some tubes use less) on the GM tube.   

Offline klugesmith

  • High Voltage Engineer
  • ****
  • Posts: 205
  • Karma: +5/-0
    • View Profile
Re: GM tube hv transformer
« Reply #2 on: January 24, 2020, 10:53:42 PM »
To get 2000 V for detector bias,
my first try was a small variac + tiny NST + diode, capacitor, permanently connected kV meter, and a weakening resistor between variac and NST.

Too much ripple voltage ( a volt at 60 Hz?  Some mV at 120 Hz with bridge rectifier & bigger capacitor ) for the Charge Sensitive Preamplifier and my proportional counter tube.  When checking ripple voltage with your oscilloscope in AC-coupled mode, mind the kilovolts.

Then I went out and bought an old NIM Bin, and a 0 to 5000 volt bias generator module to plug into it.
The 1960's or 1970's design has an 8 or 10 stage voltage multiplier, following a small transformer running at 25 kHz, driven by a multivibrator made from discrete transistors.  The size of capacitors in voltage multiplier makes the output impedance about 5 megohms.

That's how I would go for a scratch-built bias supply.  As found online in many GM counter projects.
See also the HV power circuits in battery-powered civil defense instruments.

If ripple voltage is not a big concern, you might try a mains-frequency voltage multiplier, optionally following a step-up transformer.  Haversin's MOT approach is probably easier & better.  Small MOT might not need active cooling if operated at 1/3 or 1/2 of nominal voltage.

« Last Edit: January 24, 2020, 11:35:35 PM by klugesmith »

Offline haversin

  • High Voltage Enthusiast
  • *
  • Posts: 25
  • Karma: +0/-0
    • View Profile
Re: GM tube hv transformer
« Reply #3 on: January 25, 2020, 01:15:21 AM »
Too much ripple voltage ( a volt at 60 Hz?  Some mV at 120 Hz with bridge rectifier & bigger capacitor ) for the Charge Sensitive Preamplifier and my proportional counter tube.

GM tubes are generally operated in the middle of the Geiger-Muller region where there is a plateau in the counting rate verses voltage response curve. Voltage regulation within a few volts is perfectly acceptable in this region. Operation in the proportional region is at a lower voltage and close voltage regulation is required.
« Last Edit: January 25, 2020, 01:28:47 AM by haversin »

Offline futurist

  • Global Moderator
  • High Voltage Technician
  • *****
  • Posts: 138
  • Karma: +2/-0
    • View Profile
Re: GM tube hv transformer
« Reply #4 on: January 25, 2020, 11:01:24 AM »
I built a geiger counter for high school project using Wenzel's ferrite choke HV supply. It uses 555 monostable for pulse detection and electrolytic capacitor for "counting" pulses per minute
http://www.techlib.com/electronics/graphics/geiger2ind.gif

Power consumption is amazingly low, less than 1 mA, my counter still has original 2011 batteries
/>
« Last Edit: January 25, 2020, 11:14:08 AM by futurist »

Offline shrad

  • High Voltage Enthusiast
  • *
  • Posts: 45
  • Karma: +0/-0
    • View Profile
Re: GM tube hv transformer
« Reply #5 on: January 28, 2020, 12:32:39 PM »
CFL inverters make good small power supplies for GM tubes

High Voltage Forum

Re: GM tube hv transformer
« Reply #5 on: January 28, 2020, 12:32:39 PM »

 


* Recent Topics and Posts

post Re: Capacitors and arcs
[Beginners]
k42
Today at 08:53:06 PM
post Re: XRay Tank- any ideas about what is inside
[Transformer (Ferrite Core)]
HighVoltageRulezz
Today at 07:20:48 PM
post Re: Why is Auto-transformer (variac) called transformer??
[Beginners]
Morvandium
Today at 04:45:43 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
T3sl4co1l
Today at 10:57:29 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
Today at 08:55:30 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
Today at 08:48:33 AM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
davekni
Today at 07:00:13 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
davekni
Today at 06:57:36 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
davekni
Today at 05:44:54 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 09, 2020, 09:23:38 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 09, 2020, 09:09:08 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
July 09, 2020, 07:00:49 PM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
TMaxElectronics
July 09, 2020, 02:33:38 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 09, 2020, 12:16:32 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 09, 2020, 11:46:10 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
Twospoons
July 09, 2020, 10:56:18 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 09, 2020, 08:37:52 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
klugesmith
July 09, 2020, 06:45:18 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
TMaxElectronics
July 09, 2020, 02:36:22 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
Mads Barnkob
July 08, 2020, 09:43:20 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
Morvandium
July 08, 2020, 09:33:35 PM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
johnf
July 08, 2020, 09:23:14 PM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
klugesmith
July 08, 2020, 09:16:42 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 08, 2020, 09:00:04 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
Mads Barnkob
July 08, 2020, 04:25:53 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
ElectroXa
July 08, 2020, 10:03:25 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 08, 2020, 08:39:10 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
Twospoons
July 08, 2020, 08:34:02 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
davekni
July 08, 2020, 04:39:10 AM
post Measuring LED efficiency
[Light, Lasers and Optics]
TMaxElectronics
July 08, 2020, 12:46:23 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 07, 2020, 10:28:37 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
ElectroXa
July 07, 2020, 10:09:22 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 07, 2020, 09:36:53 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 07, 2020, 09:20:12 PM
post Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 07, 2020, 09:07:10 PM
post Re: Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
T3sl4co1l
July 06, 2020, 10:29:17 PM
post Re: induction heater troubleshooting help
[Electronic Circuits]
petespaco
July 06, 2020, 06:53:26 PM
post Re: adventures in homemade flyback bobbins.
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 06, 2020, 01:18:03 PM
post Re: Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 06, 2020, 01:05:32 PM
post Re: Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
T3sl4co1l
July 06, 2020, 06:14:56 AM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
July 05, 2020, 06:31:21 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
HiVi
July 05, 2020, 12:30:02 PM
post Re: IGBTs keep dying (un-solved again)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 04, 2020, 10:35:50 PM
post Re: IGBTs keep dying (un-solved again)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 04, 2020, 08:56:15 PM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 04, 2020, 04:37:32 PM
post Re: IGBTs keep dying (un-solved again)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 04, 2020, 04:14:44 PM
post Dell PowerEdge M1000E Blade Server Teardown
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Mads Barnkob
July 04, 2020, 01:52:14 PM
post Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 04, 2020, 12:37:48 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 04, 2020, 12:17:47 AM
post Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
July 03, 2020, 07:12:18 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal