Please read the description/textbox first. This is VLOG 1, showing a 3 transistor oscillator (= function generator) usable for many purposes.
More to come in the following video’s. Frequency range will be showed, but when you make it “as it is showed” (say on a breadboard) you can surely see the frequencies where it oscillates.
The circuit is also a differentiator and an integrator circuit, combined with that oscillator on different frequencies.
It is working in a broad frequency band (test/try, precise frequency info will follow), but I want to develop the circuit further for other/more frequency bands.
Simply making it is the first aim for every serious electronics amateur.
Surely you can get now, with the circuit “as it is”, good results when you want to produce needle waves/pulses (say to drive MOSFETS) or kind of (…) square waves (with different pulse-pause ratio’s) via changing the capacitor values in the circuit & aligning the potentiometers.
About frequency dependent capacitors I mean: between the Collector and the Bases of the 2 transistors. In one case that is a Darlington, by the way. That Darlington consists of a BC 547 B and a BD 139.
Also (simple, not very linear) sawtooth waves can be generated via the 3 transistor circuit “as it is”. Showed here on YT.
The waveforms are (e.g.) usable to drive a cathode ray tube on its horizontal axes. This has to be a sawtooth wave, by the way, as pure (sharp & linear) as possible, between 0 Hertz and (say) 500 KC for a simple oscilloscope, going to approx. 3 MC or so.
Elaboration: you can drive a Cathode Ray Tube (CRT) via a sharp (read pure) sawtooth wave on its horizontal deflection, be it a static deflection television tube or not, say deflection via coils on the neck of the tube.
Driving a CRT via currents on the neck of such a tube is (in practice) often not good in linear (due to the coil properties) terms and the deflection coils on the CRT also limit high frequencies. Old school electronics technology, by the way.
In general coil deflection of a cathode ray tube (via currents in the deflection coils) works to max. 18 KC (my experience).
But all of this is very useful and good to create and show all kinds of figures/waveforms on such an old school TV cathode ray tube. More in the book that I mention on the LULU website (Schematics 3, below).
Interesting/Interested? Driving via say HV Darlington, by the way, consisting of 2 HV Transistors, like the 2SC2333, the horizontal axis. It gives a primitive horizontal amplifier solution, comparable to the 1920’s-1940’s circuits, where thyristor tubes did that work.
Thyristor tubes (though very specialized, 1930-1960's) are in a certain way comparable to neon tubes in the past. Both tubes have the effect (in their bare essential physics properties) of a "break-through" on voltage X in their gas pillar. So suddenly the gas pillar conducts in electric terms when a certain voltage is applied or when the voltage parallel to the tube gets too high.
Thus this "breakthrough" effect was also used to generate the horizontal line on basic oscilloscopes in the 1920’s etc. Up into the 1950’s. Can also be used now, 2022. Physics practice (and theory).
Simple (simplified) circuits about this all are available in my book on the LULU website, title “Schematics 3, transistor switches, generators and cathode ray tube circuits.
ISBN 978-1-4476-1164-6. Or LULU content number 10469565 (on the LULU website).
My You Tube channel trailer is here: https://youtu.be/xbgQ8T3oqh4 When you search, search always “NEWEST FIRST” to get the right overview. You can also search via the “looking glass” on my Channel trailer via keywords like ”audio”, “radio”, “amplifier”, “filter”, “Shortwave”, “transistor”, “FET”, “oscillator”, “generator”, “switch”, “schmitt trigger” etc; so the electronic subject you are interested in. My books about electronics & analog radio technology are available via the website of "LULU”, search for author “Ko Tilman” there.
https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=Ko+Tilman
I keep all my YT videos constant actual, so the original video’s with the most recent information are always on YouTube. Search there, and avoid my circuits that are republished, re-arranged, re-edited on other websites, giving not probable re-wiring, etc. Some persons try to find gold via my circuits. I take distance from all these fake claims. I can not help that these things happen. Upload 6 August 2022.