This TTL heads or tails circuit was found in the July 1973 Radio Electronics magazine. The LEDs are types of the time. Note the symbolic representation of this component.
We present a circuit formed by six voltage comparators. Each comparator will analyze the voltage...
This circuit can generate time base signals from 5 to 1500 Hz. We find it in a documentation about old neon...
In this circuit the CA3140, an operational amplifier, is used as a comparator with the zener diode...