Found in an old Popular Electronics this circuit is still current. The SCR can be of the 106 series and the relay according to the voltage used in the supply. The voltage can be 12 V.
This circuit is an excellent application for the PIC in audio, but the reader who intends to do...
To a 16-0hm load, this amplifier provides a power of 10 W. We found this circuit in a Motorola...
This reader with TTL logic compatible output uses an LM139 comparator. The circuit was found in...