The integrated circuit used in this circuit is from the time of publication. The circuit is from a Radio Electronics from October 1987. The triac must be equipped with a heat sink.
Originally this circuit is from an English magazine, but I found it in Argentina's Radio Chassis...
This circuit was obtained in a 1967’s EEE. Transistors and integrated circuits can be replaced by...
In the figure we have a simple amplifier stage for BC547 series transistors. The gain is...