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.
This circuit, from ancient French documentation, produces a rectangular pulse from input pulses...
This control is from the Motorola Circuit Applications for the Triac of 1971. The Triacs can be...
This circuit is from 1964 documentation but can be easily implemented based on current components....