This circuit for light modulated in frequency (FM) operating at 50 kHz was found in a 90’s Electronics Now. The circuit has an active filter. Modern equivalent transistors can be used.
Intended for use with signals from tape recorder pickups, this circuit was found in the December 1972...
In the figure we have the configuration of a voltage regulator with 3 transistors. The components depend...
This circuit was found in an 80s documentation. The integrated circuit used is from that time,...