This circuit for 12 V relays was found in the July 1992 Radio Electronics magazine. The circuit is set at R6.
This receiver for an audio link by modulated light was found in a 90s Elektor. Transistors are common...
This video game that we published at the same time the full article in the magazine Eletrônica was also found...
This circuit can be used as a shield for transmitting the temperature of a sensor. The circuit is from...