Author Topic: GM tube hv transformer  (Read 1139 times)

Offline AlexanderHun

  • High Voltage Enthusiast
  • *
  • Posts: 36
  • 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: 27
  • 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: 252
  • Karma: +6/-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: 27
  • 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: 147
  • Karma: +3/-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: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
Today at 05:50:56 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
Today at 02:59:47 PM
post Re: VTTC on GU-81M
[Vacuum Tube Tesla Coils (VTTC)]
Continuum
Today at 12:18:10 PM
post Re: steam engine
[Capacitor Banks]
plasma
Today at 09:49:57 AM
post Re: steam engine
[Capacitor Banks]
Zipdox
Today at 09:18:53 AM
post Re: Am I Misunderstanding of DC Blocking Capacitors
[Solid State Tesla Coils (SSTC)]
Zipdox
Today at 09:13:12 AM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 06:45:24 AM
post Re: DRSSTC driver
[General Chat]
Mads Barnkob
September 20, 2020, 08:37:58 PM
post Re: Current transformer for narrow spaces
[Laboratories, Equipment and Tools]
klugesmith
September 20, 2020, 05:31:25 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GKnapp
September 20, 2020, 05:20:51 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
Uspring
September 20, 2020, 03:46:15 PM
post Re: How do you all pronounce kluge or kludge?
[General Chat]
Uspring
September 20, 2020, 03:25:48 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
September 20, 2020, 02:12:35 PM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GKnapp
September 20, 2020, 02:02:34 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
Hydron
September 20, 2020, 01:27:52 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
Mads Barnkob
September 20, 2020, 11:58:14 AM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
friday
September 20, 2020, 07:53:30 AM
post Re: How do you all pronounce kluge or kludge?
[General Chat]
johnf
September 20, 2020, 06:09:20 AM
post Re: How do you all pronounce kluge or kludge?
[General Chat]
MRMILSTAR
September 20, 2020, 05:58:46 AM
post Re: Am I Misunderstanding of DC Blocking Capacitors
[Solid State Tesla Coils (SSTC)]
T3sl4co1l
September 20, 2020, 04:40:21 AM
post Re: DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 20, 2020, 02:22:28 AM
post Re: Cheapest source so far for step adjustable DC power for ZVS induction heaters
[Electronic Circuits]
davekni
September 20, 2020, 02:06:56 AM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
Hydron
September 19, 2020, 11:34:01 PM
post How do you all pronounce kluge or kludge?
[General Chat]
klugesmith
September 19, 2020, 11:21:11 PM
post Re: Am I Misunderstanding of DC Blocking Capacitors
[Solid State Tesla Coils (SSTC)]
klugesmith
September 19, 2020, 10:13:44 PM
post Re: Fat wire for facility (a house)
[Laboratories, Equipment and Tools]
johnf
September 19, 2020, 09:40:56 PM
post steam engine
[Capacitor Banks]
plasma
September 19, 2020, 07:54:41 PM
post DRSSTC driver
[General Chat]
octopus1
September 19, 2020, 04:50:28 PM
post Re: Join Kaizer Power Electronics, Youtube channel now has memberships
[Crowdfunding]
Mads Barnkob
September 19, 2020, 04:50:23 PM
post Re: Cheapest source so far for step adjustable DC power for ZVS induction heaters
[Electronic Circuits]
petespaco
September 19, 2020, 03:27:57 PM
post DRSSTC Tuning for Music vs Big Sparks?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GKnapp
September 19, 2020, 01:41:14 PM
post Re: Fat wire for facility (a house)
[Laboratories, Equipment and Tools]
Mads Barnkob
September 19, 2020, 11:09:16 AM
post Am I Misunderstanding of DC Blocking Capacitors
[Solid State Tesla Coils (SSTC)]
werd
September 19, 2020, 08:13:55 AM
post Re: Cheapest source so far for step adjustable DC power for ZVS induction heaters
[Electronic Circuits]
davekni
September 19, 2020, 01:31:34 AM
post Cheapest source so far for step adjustable DC power for ZVS induction heaters
[Electronic Circuits]
petespaco
September 18, 2020, 11:58:14 PM
post Fat wire for facility (a house)
[Laboratories, Equipment and Tools]
klugesmith
September 18, 2020, 10:35:59 PM
post Re: SSTC or DRSSTC with GaN Transistors
[Solid State Tesla Coils (SSTC)]
Hydron
September 18, 2020, 05:29:24 PM
post Re: SSTC or DRSSTC with GaN Transistors
[Solid State Tesla Coils (SSTC)]
Zipdox
September 18, 2020, 03:52:08 PM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
flyglas
September 18, 2020, 02:49:05 PM
post Re: IGBT Temperature
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
September 18, 2020, 11:56:58 AM
post Re: IGBT Temperature
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Weston
September 18, 2020, 10:31:58 AM
post Re: Eensy weensy switchmode power supplies
[Electronic Circuits]
T3sl4co1l
September 18, 2020, 08:19:19 AM
post Re: Upper audio frequency interruption of HFSSTC
[Solid State Tesla Coils (SSTC)]
davekni
September 17, 2020, 11:18:25 PM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
Hydron
September 17, 2020, 10:26:57 PM
post Re: SSTC or DRSSTC with GaN Transistors
[Solid State Tesla Coils (SSTC)]
Weston
September 17, 2020, 09:13:40 PM
post Re: Upper audio frequency interruption of HFSSTC
[Solid State Tesla Coils (SSTC)]
uzzors2k
September 17, 2020, 09:02:42 PM
post Re: Eensy weensy switchmode power supplies
[Electronic Circuits]
klugesmith
September 17, 2020, 07:46:08 PM
post Re: Rogowski current probe
[Laboratories, Equipment and Tools]
flyglas
September 17, 2020, 07:43:00 PM
post Re: SSTC or DRSSTC with GaN Transistors
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
September 17, 2020, 10:23:29 AM
post Re: Eensy weensy switchmode power supplies
[Electronic Circuits]
T3sl4co1l
September 17, 2020, 06:56:59 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