Geiger Counter Electronic Circuit / Schematic

This link is a comprehensive resource for building your very own geiger counter radiation detector, using a Geiger Muller tube. The circuit is capable of measuring alpha, beta and gamma radiation, the three primary forms of radiation.

The circuit produces a flashing LED and audible click on a speaker when radiation is detected.

This link goes to the front page of the geiger counter resource, and you will need to navigate through about 5 or 6 pages in order to see all of the Geiger counter information and circuit diagram

• GM Geiger Mueller Tube
• T1 HV mini step up transformer
• C1 .0047 uF capacitor
• C2 .01 uF capacitor
• C3,C10 100 uF capacitor
• C4,C5 .01uF 1KV capacitors
• C6 1.0 uF 12V capacitor
• C7 .047 uF capacitor
• C8 .01 uF capacitor (16v)
• ----
• D1 1N914 diode (or equiv.)
• D2,D3,D9 1N4007 1KV diodes
• D4 1N5271 100 volt zener diode
• D5,D6 1N5281 200 volt zener diode
• D7 Red LED Chrome case with mounting hardware
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• SPK Speaker
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• R1 4.3K ohm 1/4 watt resistor
• R2 15K ohm 1/4 watt resistor
• R3 5.6K ohm 1/4 watt resistor
• R4 10 mega ohm 1/4 watt resistor
• R5 470 K ohm 1/4 watt resistor
• R6 100 K ohm 1/4 watt resistor
• R7 47 K ohms 1/4 watt resistor
• ----
• SW1 Panel Mounted On-Off switch
• SW2 Panel Mounted On-Off switch
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• U1 4049 Hex Inverting Buffer
• U2 555 Timer
• U3 7805 Voltage Regulator
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• Q1 IRF830 MOSFET Transistor
• Q2 2N3904 NPN Transistor
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• 2 x 9-Volt battery terminals PC mount (PCB only)
• 1 x 470 ohm 1/4 watt resistor (for optional headphones)
• 3 x 3.5MM jacks (For additional options; head phones; digital out, external power supply)
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• 1 x Nylon screw and nut (2-56) for mounting PCB to enclosure)
• Misc: Case, LED holder, LED cable, On-OFF switch, 9V battery cap, Geiger Counter Case