Kinks White Noise Generator

Hello :slight_smile:

I’m trying to understand how the kinks noise generator works. I would love to build a DIY Geodesics Branes, so I’m very interested how to generate noise.

First. I’m not an expert. I’m just willing to learn things. I do some calculations of the Q Point of Q2 and tried to calculate the noisy ac output voltage, but I’m not sure if this is right, cause I never worked with noise before in such a way.

Then I build a test circuit with some BC547B (I don’t have some MMBT3904 here), but the test was a big fail. I did not understand why I could measure a V_BEO Voltage of 10 Volts or more. Shouldn’t the transistor Q1 work in breakdown? (for the BC547B V_BEO = 6V, too I think). And my DC voltage at V_out was almost Vcc (12V).

I didn’t understand anything. Is this only because the choice of another transistor? (I thought they have similar characteristics) Is my calculation false? I don’t get it.

I already asked some of my fellow students to help and get some interessant answers: They mean I should use a Emittier Resistor with a bypass cap to stabilise the Q Point, but in the Kinks module its working without one…

So I would be very helpful for any kind of help :smiley:

THX and double THX
Gruftgrabbler

EDIT: I forgot to check my assumption that Q2 is working in saturation mode:

V_CE2 > V_CE,SAT = 0,2V
1,4V > 0,2V so the assumption was correct

I’m afraid I can’t help you with this, this was designed with the very helpful technique of “trial and error”.

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Haha I like your approach, maybe I will try this, too :stuck_out_tongue: And maybe I will hear to my fellow students and add some q point stabilisation :slight_smile:

It’s been ages since I dabbled in electronics but I came across a similar schematic that may provide some answers:
https://www.eeweb.com/extreme-circuits/simple-white-noise-generator

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