5 Simple audio amplifier circuit diagram using transistor

These are many simple audio amplifier circuit diagram using transistor. Currently, ICs has been used in many audio amplifiers, especially small circuit. It is convenient to use transistors.But when you need to use transistors, it has several advantages, such as saving you can take old equipment come to made small circuits easier than the IC. Which may be difficult to find. Take a look at these circuits. Maybe you get the idea of it.

Here are projects ::

The Simple Audio Amplifier with NO ICs

1.) Low impedance mini amplifier

Low impedance mini amplifier

This circuit can apply to signal sound source that has low impedance , such as from 4-16 ohm size loudspeakers or telephone earphone that use to replace , Micro phone. If use a loudspeaker replaces the rapidity will enough in sound checking that has been born from walking. The output this can feed reach input of high power amplifier the other next.

2.) Power Amplifier OTL using AC176+AC126

Power Amplifier OTL using AC176+AC126

Mr Somsak is my friend who like to make power amplifier so much. but he do not well electronic man. I so introduce he need make easy project before. This circuit is simple power amplifier OTL that mini watt output but is older circuit.
They uses transistors example number are AC176 , AC126 and BC109. which there has other a few components. They are used power Supply Voltage 9Volt only. I hope it will be once circuit so you like and well ideas.

3.) Power Amplifier OTL Cassette Radio Booster using TIP41+TIP42

Power Amplifier OTL Cassette Radio Booster using TIP41+TIP42

This is mini Power Amplifier OTL for Cassette Radio Booster. it have transistor TIP41 + circuits of TIP42 Drive speaker sound. Volt supply see in image.

4.) Simple Amplifier using Transistor AC128

Simple Amplifier using Transistor AC128

I find this in my old circuit electronics book. It is very a small power amplifier, but good quality audio class AB amplifier in hi-fi applications. The component capable of delivering 2W continuously an used the AC128 thansistor into a 8 ohm load and 5W peak. with the proper 9 volt unregulated power supply.

Sharing is caring!

Related Posts


I always try to make Electronics Learning Easy.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

newest oldest most voted
Notify of

any replacement for the ac128 transistor , cause they dnt make it any more


thank u so much for this circuits


Hi you have made a mistake with the part number for the transistors in the mini amplifier, you have 2n3094 that is a SCR,i think what you meant was 2n3904 correct me if i am wrong, THANKS.


Power Amplifier OTL Cassette Radio Booster by TIP41+TIP42: Good circuit! Just C1 and C2 should have opposite polarity, also I assume C3 (I used bipolar one).

Harry Layne BSc

I built this circuit and it works well. I used a 9 volt power supply filtered with 2500uF capacitor. The output transistors should be mounted on 16 guage aluminium heatsinks approx 6 x 4 CM for each transistor. The 25k resistor can be a preset, adjust for best sound snd current. It serves me well as a Test Bench amplifier. H.L


Nice circuts…it works too

Close Menu