Please read the description first.
The video shows one of the circuits of an audio-pre amplifier that I published in an earlier video on YouTube, yesterday. I published there (link below) 2 circuits of audio pre-amps, working on 3 Volt (minimum 2.2 Volt) that were made with electret microphone capsules.
Links to the schematics and the demo (upload 15 July 2024):
[ Ссылка ]
Earlier video is here [ Ссылка ]
These High Quality microphone capsules are very cheap now (2024) and have extremely good properties, when amplifying sound(s) between (say) 50 Hertz and 14 KHz (KC).
So Hi-Fi sound amplification, and that does not have to an be expensive electronic circuit.
Also suitable to make good quality audio recordings. I did that many times in the past.
When you are somewhat acquainted with audio electronics, you can surely use this setup.
Take the signal out of the emitter of the Darlington = the second transistor of it, that is normally connected to the headphone via its emitter to ground.
To do that: connect (instead of that 32 Ohm or 15 Ohm Headphone) a 32 Ohm (or even a 47 Ohm) fixed value resistor from the emitter too ground, minus (-).
At the same time: take out the amplified microphone signal at the emitter of the Darlington via non-polar capacitor of 2.2 uF (also 470 N will work!) out opposite to ground (-).
You can also use an electrolytic of (say) 2.2 uF but they are polar and can deteriorate withing (say) 10 years. That is why I am talking about a "non polar" output capacitor in the order of 220 N or higher, up to 2 uF.
Such an electret microphone capsule costs 2 Euro’s or so. And, with this circuit, you have a perfect (=good working) microphone pre-amp in the audio range, say 50 Hz-14 KC. Working on 3 Volt, even when the batteries are depleted, say on 2.2 Volt.
Problem could be that it takes a too high supply current.... Say 30 mA-10 mA. Say 30 mA in case of a fully charged battery (3 Volts = 2 x a 1.5 V Carbon Zinc or Alkaline battery in series).
In the depleted situation the current to the circuit goes to (say) 10 mA at 2.2 Volt. Could be, with extensive use, you need 2 “fierce” 1.5 Batteries, anyway.
My You Tube channel trailer is here: [ Ссылка ]
Type there the keywords that you like (e.g. radio/audio/amplifiers/test/filter/) in the “looking glass” = search function” and give “enter”. Via that you can find specific video’s (under the say 1500 published).
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. [ Ссылка ]...
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. Upload 16 July 2024.
