This indicator with the integrated circuits CA3162E and 3161E was published in the July 1990 issue of Radio Electronics magazine. The circuit can be used as a basis for 3-digit projects.
This is the basic configuration of a monostable TTL with the 74121. The trip is done with an NC...
This fixed source configuration with 78xx series regulators has already been explored in several...
In the figure we have a TTL logic interfacing circuit as CMOS logic using a 6N139 optocoupler...