This circuit was found in an American 1990s documentation. It can directly trigger a triac when light is detected by the sensor. The integrated circuit is common, like the 741.
This oscillator does not carry any resonant circuit, except for the one formed by the crystal...
This is the circuit of a small commercial amplifier from the 1970s from Philips Argentina. The...
This powerful high-fidelity amplifier was described in an article in Radio Electronics magazine in...