This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the lighting point of the LEDs. The circuit is for 12 V automotive batteries.
This heartbeat sensor circuit was found in the July 1992 issue of Radio Electronics magazine. The...
We found this circuit in the 1982 SGS integrated circuit manual. The integrated circuit is not...
This TTL pulse stretcher or stretcher was found in a 90's EDN. The time constant R x C1 determines...