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.
In the figure we have a simple timer with two voltage comparators of the four of an LM339. The...
This circuit can be used in a signal level indicator with LEDs. The circuit is from an Electronics Now...
This circuit, found in an old magazine of the year 1968, uses a Power germanium transistor. This...