Quote from: larry_vw_1955 on November 08, 2022, 02:16:18 AM

Quote from: n0nce on November 07, 2022, 08:42:40 PM

Actually it's not complicated at all. Of course your average Joe won't build his own avalanche noise PCB, but someone with electrical engineering skills should be able to whip a circuit up and order a PCB within an afternoon. It's honestly a simple circuit.

I mean as far as general electronics circuits go, I guess it is simple if you compare it to something like a computer motherboard but that doesn't mean it is simple to understand how it works.

It's not that easy to understand from just a PCB picture, but combining it with the schematic, it gets a lot simpler. A true open-source-hardware device provides all of those files, just like here:
https://github.com/Foundation-Devices/passport-electronics/blob/master/Main%20Board/Documentation/Schematic%20Print/SCH_FD-JL-PCB-MB_E1.PDF

Quote from: larry_vw_1955 on November 08, 2022, 02:16:18 AM

And why it needs so many components to work. I didnt count them all but it looks like around 50 discrete components. I don't understand why it needs that many. I thought just one single zener diode is all you need.

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Well, the zener is the core component, but you need a driver and sampling circuit around it. Did you count the components or the pads? I count roundabout 20 components (~40 pads). The design by betrusted.io even manages to work with 14 components; look how tiny it is.

Quote from: https://betrusted.io/avalanche-noise.html

Again, if you check the schematic, it's definitely much easier to understand what it's doing, especially if you have such good resources online that help you understand it as well.

Quote from: https://betrusted.io/avalanche-noise.html

Quote from: larry_vw_1955 on November 08, 2022, 02:16:18 AM

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Trust me, it's not a pain. Foundation Devices have such circuits in their hardware wallets and the USB RNG you linked to, may have the exact same thing inside it, as well.

I think it does:
The TrueRNG Hardware Random Number Generator uses the avalanche effect in a semiconductor junction to generate true random numbers. The avalanche effect has long been used for generation of random number / noise and is a time-tested and proven random noise source.

The cost to buy theirs would probably be less than the cost to try and make one yourself. Not only monetary cost but time costs.

That just confirms that this is a good circuit. Tongue

I just wasn't aware that they're sold under the simple term 'TRNG', as I couldn't find anything when looking for 'avalanche noise circuit PCB' or so.
It would be good if these devices came with schematics and board files to verify the circuit more easily.
(1) Compare product to PCB files
(2) Compare PCB files to schematics
(3) Check schematics to understand what the circuit does and verify that it's what you want it to do