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.
This circuit was obtained from an English magazine from 1985. The N414 is a complete, not easy to...
Found on Popular Electronics from 1969, this circuit can be implemented with components that are...
This circuit is from a book of transistors from 1954. The transistors are from the time and the...