Популярное

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



Издатель
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
https://youtu.be/BM1BN98CC2A

There are more than 1000 Video’s on my YT channel. I only do analog electronics: audio amplifiers, analog measuring devices, radio circuits, many Shortwave radios, many oscillators HF and audio, other audio & shortwave circuits. Also many (test) generators for all kinds of waveforms, both in the audio range and HF. Also simple “switch” circuits like the Schmitt triggers acting on different input voltages, 555 circuits and circuits of basic electronics issues like “Ohms law”, resistance properties, capacitance properties, the capacitors testing process, electronic “matching” in audio circuits and audio amplifiers, audio pre amplifiers, microphone amplifiers, etc. In all cases you find the schematic inserted in the video.

When you have questions about (certain analog) electronic circuits and how to make them: go to my Channel trailer (Radiofun232 on You Tube) and go to the “looking glass”. Type there the keywords that you want/need like: “power supply”, audio amplifier, capacitor tester, oscillator, radio, shortwave, shortwave radio, or any keyword you like to find the essential info & schematics on my YT channel.

You can contact me via email when you have questions about my published circuits. I always ask for a picture of what you have made + a problem description; I ask to communicate. When you don’t want to give information/communicate please don’t ask help.

Sorry that I am so strict now (since 15 may 2021). It has to do with disappointing reactions in the recent past of people that asked “help” (even fake help) and did not react afterwards or asked questions when they knew the answer.

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 3 August 2021.
Категория
Усилители
Комментариев нет.