Mini audio amplifier approx. 30-50 mW, works on 3 Volts or even a lower voltage: schematic/demo/info

Please read the textbox. A (mini) 30-50 mW audio amplifier on 3 Volt or even lower voltages. The video tells everything: properties, battery use, critical components, probable distortion and how to cure it. Music: "the day is close", by the 126ers, copyright free music. They made many songs usable for demo purposes, but also easy listening. Sounds good.

Do experiments with the value of the 10 K resistor and the value of the capacitor that goes from the base of transistor 1 (BC 547 b) to the “null” = “zero” node, where the electrodes of both 1.5 Volt batteries meet.

IMPORTANT: circuit is made for battery use and is experimental, not made for beginners in electronics. Don’t connect your MP3 player or audio Smartphone output (headphone output) directly to the “node” = the “zero” wire in the electronic circuit where the + of one 1.5 battery and the – of the other 1.5 battery meet and are connected.

That can damage your MP3 player or smartphone, by adding approx. 1.5 Voltage to the headphone output of the MP3 player or smartphone.

Use that 100 N separation capacitor (in the schematic, properly explained!) and connect everything like it is showed in the schematic. This is a disclaimer.

NB: my MP3 player did not get defective when I made this faulty connection, but stopped and showed irrational behaviour (switching in/out in a random way, etc).

The mentioned capacitor that makes the input of transistor 1 “quiet” is 100 N (=0,1 uF) but you can do experiments. The circuit works and was made for 3 Volt. It was tested and after approx. 15 hours of continuous use it still worked properly without problems, voltage dropped to 2 x 1.27 volt. Started with 2 batteries of 1.5 V each, that were not completely fresh.

Don’t expect too much audio quality, compare the sound of this amplifier to a standard cheap small MW radio. Most important thing is that it must be able to work with 2 x a 1.5 Volt battery (=3 V) for x hours. The transistors (BC 547 b NPN and the BC 556 b PNP) need no cooling, they don’t get warm.

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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 22 september 2021.
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