This circuit activates a horn from an audio signal. This can be used for remote control via audio signals. The circuit is from a Radio Electronics from October 1965.
Found in the 1976 Siemens transistors manual, this circuit works with AM or FM IF signals. In the...
Three 4011 NAND gates and two more components - a resistor and a capacitor make this oscillator very...
This photoelectric circuit was found in a 70’s Ferranti's documentation. The circuit uses an...