IC power amplifier BA546
Let's make an audio power amplifier that can activate the speaker, using an audio power amplifier IC. The IC used in the project is one that has been developed for use in portable radios, radio-cassette tape recorders, intercoms, etc. It can produce an output of about 700 mW.
Using this IC, you can change the amplification rate according to the value of R1. The amplification rate Av is about 2400/R (value of the resistor). So, it is about 9 when R1 = 270 ohms.
To use this project, connect a germanium radio, earphone-type radio, radio-cassette tape recorder, etc. to the input terminal, then turn the control volume to adjust the sound volume from the speaker.