Found in documentation from the 1980s, this circuit is used for resistive loads (incandescent lamps). The triac must be equipped with a heat sink.
This is a commercial radio circuit from the 1960s. The circuit was found in a Japanese publication from...
The integrated circuit used in this 80's differential amplifier is a quadruple version of the 741...
This touch or proximity sensor circuit was found in a Popular Electronics from 1992. In the...