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It's hard to build an oscillator

(lcamtuf.substack.com)
219 points chmaynard | 4 comments | 21 Nov 25 07:45 UTC | HN request time: 0.72s | source
1. jhallenworld ◴[21 Nov 25 13:43 UTC] No.46004532[source]▶
Easy negative resistance oscillator: a neon bulb in parallel with a capacitor connected to a DC power supply through a resistor.
replies(2): >>46005368 #>>46007119 #
2. IAmBroom ◴[21 Nov 25 15:20 UTC] No.46005368[source]▶
"Negative resistance"? Are you sure that's what you mean? Cuz it isn't.
replies(1): >>46005573 #
3. jhallenworld ◴[21 Nov 25 15:46 UTC] No.46005573[source]▶
Yes, it is... (negative differential resistance to be more precise)

https://en.wikipedia.org/wiki/Pearson%E2%80%93Anson_effect

https://en.wikipedia.org/wiki/Negative_resistance

4. zhrvoj ◴[21 Nov 25 18:18 UTC] No.46007119[source]▶
I built many such oscillators same way. But I used BC107 NPN, connected collector to the ground, emmiter to resistor/capacitornet. Base free. Add LED in series with such connected transistor, and you have LED blinker.