It is not every day that we find a web site or a YouTube video that discusses negative resistance and the Barkhausen criteria. But that day has arrived my friends!
This All Electronics fellow appears to be Italian. I really like his enthusiasm. The universe! Differential equations! The passion seems to jump out of the video when he talks about how the negative resistance "enhances the oscillation!" It is really great.
He even talks about how thermal noise gets the oscillation going. This is something that I struggled with as a kid. It took me a while to find a good source that explained this. He explains it very well.
Thanks to master homebrewer Pete Juliano (another Italian!) for alerting us many years ago to the Barkhausen criteria. And thanks to Al Williams at Hack-A-Day for alerting us to this great video.
Here is the All Electronics channel on YouTube: https://www.youtube.com/@AllElectronicsChannel
Excellent, excellent Video on the subject. HP engineering had all sorts of methods to extend range and improve phase noise.
ReplyDeleteBack in the 70's, a very sage Analog designer of many years experience told me "You cannot make a oscillator oscillate at more than one frequency". To that all I said was "SuperRegen, Armstrong, 1922". After realizing to every rule there are exceptions, he said "Wait a minute, I meant L-C Oscillators, you're cheating with an L-C oscillator being quenched by a Relaxation oscillator". My reply, "you said oscillator, and that can be done with just one active device".
I put ARRL Handbook on his desk, and said, "It's all in here, keep it and get your amateur license, so you do Homebrew."
73!
Remember the Western Electric Touch Tone keypad ? An LC oscillator using one PNP transistor which generated 2 tones :)
DeleteWhen I hear: "All Electronics" I immediately think of a now defunct mail order surplus place in Van Nuys CA - I still have stuff from them I haven't used yet :)
Best Regards,
Chuck, WB9KZY
Correct!! One PNP, two tones. Check out:
Deletehttps://www.facebook.com/groups/ElectronicParts/posts/2574104306112222/
73!