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If you own a Geiger or Scintillator counter that was built in the forties or fifties, it probably has vacuum tube circuitry.
Vacuum tubes require a higher voltage to operate than transistors and integrated circuits. (vacuum tubes need at least 60 volts and some operate at 90 volts.) The batteries were usually 45 or 67 1/2 volt for the plate voltage and 33 volt for the bias voltage. At the time, even radios used tubes, and the batteries were common and easy to get.
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We now have Alkaline batteries that have high current capacities in the 1 1/2 volt size. ( Duracell capacity ratings)
AA Alk. 2850 MAH = Milliampere Hours.
C Alk. 7800 MAH
D Alk. 15,000 MAH
To translate what this means, if you put a AA Alk. battery in a circuit that uses 40 milliamperes to operate, the battery will have a useful life of 71.25 hours. At the same rate (40 MA) a D size would run for 375 hours.
With todays new components you can replace the old high voltage (and high priced) batteries with a step up power supply that will take 6 volts ( 4 X 1.5 volt cells) and turn it into all of the high voltages that run the detector.
As an example the Detectron Model DS288 uses 1- 67.5 volt battery and 2- 33 volt batteries. With the step up power supply using 4 - C cells using 40 MA. will run for 195 hours. The cost of the four C cells is approximately $4.50. This translates to about two cents an hour of running time. If your unit has enough room for D cells you can operate for 375 hours for about the same price for the batteries. ( Running time is based on the battery capacity and running continuously until battery capacity is reached.)
Please E-mail for ordering information. allnilo@netzero.com
This is a photo of a power supply that I offer for the Precision model 106B and 107C. Other power supplies are available on request.
CLICK to see instructions for 107C
CLICK to see instructions for 106B
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