This circuit is from Radio Electronics from March 1977. The integrated circuit is from that time and the circuit is intended for an infrared audio link. The modulation is in pulse frequency.
This 5.1 MHz oscillator was found in a 1980s American documentation. The used operational...
A NOR gate can be improvised using one NAND gate of a 4011 as shown here. The diodes are...
Found in the September 1982 issue of Radio Electronics magazine, this circuit triggers a relay...