We found this circuit in a 1965 magazine. The circuit can be assembled with current equivalent transistors and the precision in generating the frequencies depends on the tolerance of the capacitors.
With the circuit shown in the figure we have a frequency modulation which is produced by a...
This is a circuit found in a 1970's Radio Electronics. The circuit works with virtually any triac...
This circuit was found in a 1970s RCA publication. Transistors support modern equivalent types....