In many audio applications, regulating the audio signal to a constant level is very important.
This is true specially for voice modulated radio transmissions. Voice regulation is also often applied in intercom devices
or telephone systems. Such a voice level regulator need not be very expensive.
The circuit featured here combines
simple design with inexpensive materials. This simple audio compressor uses a straightforward regulation technique to
constantly control the amplitude of the output signal. In contrast to common feedback techniques where the output is used to
regulate the input signal, the output signal of this circuit is being regulated by the input signal.
This technique simplifies the overall design of the circuit. Surprisingly, the transistor T2 works as the only active component in the circuit.
This compressor functions very well in intercom systems or in radio transceivers. It can also be used in PA systems or telephone devices such as automatic answering machine.
Printed Circuit Layout
Parts Placement Layout
Electronic Circuits volume 1.0 - Circuit Nr. 5
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
Click on the image to view the book.