Mini audio amplifier say 100 milliwatt on 8-9 Volt, takes 50 mA at 9 Volt schematic/demo

A simple mini audio amplifier for 50 MilliWatt audio output with good properties made to work on (say) 9 volts. Correction: on 6.16 I say "on which frequency there is no distortion" but of course I mean: "on which supply voltage there is no distortion". Sorry for that.

Problem is (or could be) that it draws 50-60 mA constantly, due to the say direct connection of the 2 bases of the end transistors: BC 547 (NPN) and BC 557 (PNP) via that 190 Ohm/470 Ohm resistor.

You can surely experiment to bring that constant current down (experimenting with the values of that 470 Ohm resistor and the 190 Ohm resistor on different supply voltages). I am always interested in such experimental results.

Interesting: the typical crossover distortion showed related to the biasing of the first transistor.

Anyway: an interesting and usable circuit, but perhaps not for battery (say a 9 Volt type) use. Please note: 3 Volt amplifiers of (say) simple MW radio’s (= using two 1.5 Volt batteries in series) are made with very special properties. I could explain how that was done, but not in this video.

Surely this circuit is usable when it could be supplied out of the mains supply delivering a voltage of 8-9 Volt DC.

Or: supplied via NiCad or NiMH rechargeable batteries that can deliver that current (50 mA) for many hours. That could be a real option for this tiny power (50 mW) amplifier.

But (!) of course there are much better audio amplifiers for such a use, say working between 3 Volt or 8-12 V to 18 V DC. Many circuits of such amplifiers are on my YT channel + in my book. 1 (one) audio amplifier for 3 Volt is in my book. With better I mean: class B and a tiny quiescent current. A very low quiescent current is neccesary for battery applications. Otherwise they are quickly depleted.

I am always experimenting and this shows a good and successful experiment. And thus this circuit is usable.

First video (non-linear amplification, only usable to amplfy BEEP signals) is here

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