This circuit was found in the Electronics Experimenter Handbook from 1991. The circuit controls a simple relay for the purpose of turning circuits on or off or switching audio channels.
We find this circuit in American documentation from the 1980s. The accuracy of the circuit depends on the...
The presented circuit uses a symmetrical power source to supply an amplifier with the LM139 or...
High quality sound can be obtained from this transistor amplifier. The output transistors must be...