Please read the textbox/description. Aim of this video was to make a beeper (alarm beeper) working on only 4.5 Volt or 5 Volt with an irritating sound. More info in the video.
My idea was that many small computers nowadays (say Arduino, PIC processors, Raspberry, etc). work on 5 Volt. So this analog beeper was made to work on 5 volt.
Of course these mini computers/chips can generate sounds via a pin (that must be activated in the computer program) via which you can drive an audio amplifier with a certain (beep) signal thus in a digital way.
Anyway: this is a certain hardware solution that (also) can work on 5 Volt, when an output pin of such a mini computer is activated, made high or low, etc, and with 5 Volt, the alarm beeper is activated.
More or less everything is explained in the video. I have forgotten to turn the 220 K potentiometer in this demo video to show all the different frequencies that the circuit can bring.
When you make it, turn that potentiometer and you can hear the audio frequencies in the (say) 2 KC-8 KC range. Of course no sine waves…Only irritating or say "square wave" sounds.
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 cannot help that these things happen. Upload 31 May 2022.