Geiger Counter Project - Schematic HVPS

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etoktar
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Joined: Tue Nov 01, 2011 5:12 pm

Geiger Counter Project - Schematic HVPS

Post by etoktar »

The high voltage Power Supply has the resistor R6 (330) join with the D2 (1N914) anode in shematic project, but in PCB the resistor is R5 (1K), like the Photo. I Can´t get more than 330V to the Muller tube measuring in TP2.

When I changed the resistors labled in PCB like R5 and R6 (following the schematic Geiger), I got the min 196V and the maximum 378V (not yet 400V to SBM20).
So, the LABEL printed in PCB is wrong?

Look at the picture at the site (Geiger Kit mounted pic), the resistor label that is conected to diode D2 is the R5 (1K), but in the diagram should be 330 ohms.

I can´t get the 400V in TP2 and I revised the solders points and got it this difference bettwen the components labeld in PCB and Geiger schematic. So, the labels in PCB are rigth or the shematic Geiger Counter R5 and R6 are correct?
Thank you.
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mightyohm
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Location: Seattle, WA
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Re: Geiger Counter Project - Schematic HVPS

Post by mightyohm »

The silkscreen on the PCB is incorrect. R5 and R6 are swapped. Thanks for pointing this out!

The circuit should be assembled according to the schematic - but the fact is that it works either way (all of the kits I have built since the prototype have been with R5/R6 reversed, and I had not even noticed a difference in performance).

The voltage range will be affected, as you have noticed, but your measurements are low because your DMM is loading down the circuit - please see my reply to your other post.
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