This circuit was suggested by an Electronic Design from the 90s. Its purpose is to detect resistance relationships in circuits with resistive sensors for control purposes, by firing a relay.
Found in a magazine 73 for radio amateurs of the 90s, this circuit shows how to supply a photo...
This circuit was found in the 1991 Electronics Experimenters handbook. It can be used to display RGB...
This sinusoidal oscillator was found in Radio Electronics in 1989. It uses a 741, but other...