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by mightyohm
Sun Dec 16, 2018 4:14 pm
Forum: Geiger Counter
Topic: voltage problem Geiger Counter
Replies: 6
Views: 1153

Re: voltage problem Geiger Counter

There is an archived version of that page here: https://web.archive.org/web/20120626122 ... probe.html
by mightyohm
Sat Dec 15, 2018 11:03 am
Forum: Geiger Counter
Topic: voltage problem Geiger Counter
Replies: 6
Views: 1153

Re: voltage problem Geiger Counter

There's some information here:
viewtopic.php?f=15&t=487
by mightyohm
Tue Nov 06, 2018 10:32 am
Forum: Geiger Counter
Topic: SMD/ESP version
Replies: 5
Views: 968

Re: SMD/ESP version

I suspect most switching NPNs would work fine for Q2. The 2n3904 is just a generic NPN.
by mightyohm
Mon Nov 05, 2018 10:00 pm
Forum: Geiger Counter
Topic: SMD/ESP version
Replies: 5
Views: 968

Re: SMD/ESP version

The HV transistor needs to be a fast switching type because it is responsible for quickly switching current through L1 in order to generate a series of high voltage pulses that are filtered to create the HV supply. I'd try the STL128DN or a similar transistor - I can't guarantee that it will work bu...
by mightyohm
Sat Oct 06, 2018 3:10 pm
Forum: General Discussion
Topic: International shipping
Replies: 1
Views: 613

Re: International shipping

Hello!

Shipping is added when you complete your purchase. As long as you enter a shipping address in Italy, international shipping should be automatically calculated.
by mightyohm
Wed Jul 25, 2018 10:05 pm
Forum: Geiger Counter
Topic: Powering Multiple Units
Replies: 1
Views: 1220

Re: Powering Multiple Units

I've done this before and haven't had an issue. It should work fine. It's possible that you are detecting cosmic rays that are triggering more than one tube at a time, although if the tubes are far separated this is unlikely.
by mightyohm
Thu Jul 05, 2018 1:20 pm
Forum: Geiger Counter
Topic: Feedback first assembly.
Replies: 1
Views: 1090

Re: Feedback first assembly.

This is great feedback and should help folks trying to source replacement parts locally. Thank you very much!
by mightyohm
Tue Jul 03, 2018 8:53 am
Forum: Geiger Counter
Topic: Geiger Counter IoT
Replies: 3
Views: 5554

Re: Geiger Counter IoT

Bob, This is actually somewhat challenging to do because the high voltage supply is not capable of delivering much current to a load. The high voltage power supply is fine for powering a geiger tube, but probably would not be able to supply enough current to a voltage divider and an ADC. It's someth...
by mightyohm
Mon Jun 25, 2018 11:29 pm
Forum: Geiger Counter
Topic: Android Solution
Replies: 1
Views: 914

Re: Android Solution

This is very cool, thanks for sharing!
by mightyohm
Sun Jun 17, 2018 9:24 pm
Forum: Geiger Counter
Topic: voltage problem Geiger Counter
Replies: 6
Views: 1153

Re: voltage problem Geiger Counter

That all sounds fine. If I measure the HV test point with my Fluke 87 V alone (no resistor), I measure about 215V. This is when VR1 is properly adjusted for 400V as measured with a Gigaohm resistor in series with the DMM.

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