This circuit protects the speaker from dangerous direct currents that could damage it. The circuit is from an Electronics Experimenter Handbook 1993 edition.
This project was found in a documentation from 1980. It is a central of sound effects, a simple...
This amplifier for public address was found in English documentation from 1967. The transistors are from...
This circuit was found in an English magazine from 1978, but it is still current, just change the...