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.
Found in an English Maplin magazine in 1983, this circuit has an RIAA equalization. We suggest its...
The circuit in the figure generates a high continuous voltage, on the order of 40 to 6oV under a...
This circuit was found in the December 1991 issue of Radio Electronics magazine. The circuit is...