Help with HV adjustable power supplies for radiation detectors.

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John Futter
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Re: Help with HV adjustable power supplies for radiation detectors.

Post by John Futter » Tue May 05, 2020 7:31 am

yes I was talking about reputable supplies not aliexpress or banggood both of the later sell knockoffs that generally take their specs from the original but the product is nowhere near the original
this also appies to components like gate driver ics mosfets, IGBTs, RF transistors, ZVS driver boards, just see what the tesla coiling people are saying ---STAY AWAY from the chinese junk you get exactly what you pay for --high priced rubbish

Rex Allers
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Re: Help with HV adjustable power supplies for radiation detectors.

Post by Rex Allers » Tue May 05, 2020 8:19 am

John,

Any chance you could find and share a link (Mouser or etc.) to the kind of supply you are talking about?

Or details of the manufacturer/model.
Rex Allers

John Futter
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Re: Help with HV adjustable power supplies for radiation detectors.

Post by John Futter » Tue May 05, 2020 7:20 pm

Rex
I'll try
I'm in lockdown still but there are people at work who know what we bought i'll see

Cai Arcos
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Re: Help with HV adjustable power supplies for radiation detectors.

Post by Cai Arcos » Wed Jul 01, 2020 7:15 pm

After the final exams and some unexpected health issues, I'm finally able to continue working. I just got the inverters for a power supply like that demonstrated by Nathan Marshall, but before that I'm (again) revising the HV supply.

More specifically, I've found a way to use the blocking oscillator effectively: by connecting an appropiate sized capacitor across the primary (the winding between Vcc and the collector) the charging and discharging happens in a resonant way, thus the output waveform is really similar to a sinewave and the noise (using the same filter as before: another thing I have to optimize) is way down: I cant distinguish it from background (which is around 100mV). This is promising, because it's a stellar performance (with a relatively stiff output too) for very few components and a very low cost.

I'm also using this cheap chinese flyback transformer (https://www.ebay.es/itm/15KV-High-Volta ... Sw-89ZRPh7) (I say flyback because despite not having any specifications, it has two small pieces of paper separating the yoke). The turns-ratio is also really high so I can operate at really low primary voltages.
The only thing I have to figure out is how to regulate the output without including excessive noise. In the internet I've seen a transistor stealing current from the base of the original oscillator, but without lineal control that seems noisy. Any ideas?

As soon as I have everything figured out, I will post en extensive explanation (LTSpice simulations, schematics, etc)

Cai Arcos
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Real name: Cai Arcos
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Re: Help with HV adjustable power supplies for radiation detectors.

Post by Cai Arcos » Tue Jul 07, 2020 10:43 am

After becoming tired of feedback compensation shanaenigans, poor regulation and spurious oscillations, i'm now looking to linear high voltage, maida style regulators.
I've even found the fascinating LR8, a one-package, 400V, cheap, linear regulator! Wow! Is there any problems or quirks (aside from power regulation) I should be aware of?

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