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 PWM circuit was found in an American publication from 1978. It consists of a simple control that...
This circuit, from an old ON Semiconductor publication, suggests a shield to excite an LED from an...
The integrated circuit used in this application is not currently common. The circuit is from 80s...