This 50% active cycle TTL clock generates signals from 4 to 20 Hz. Its power must be supplied with 5 V and other frequencies can be generated with capacitor replacement.
This circuit was found in a Radio Electronics of July 1984. It consists of the traditional 1 A...
This circuit is from a 90's Radio Electronics. The circuit operates accurately up to about 15 kHz...
I found this circuit in an old British magazine from 1976. It is possible to test operational...