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.
Suggested by General Electric in a 1967 publication, this circuit uses the D13T1, an uncommon SCR...
This circuit was found in a Radio Electronics from May 1965. The transistor is a power transistor and in...
The thermistor used in this circuit must have a resistance at room temperature between 10 and...