Found in the July 1970 Radio Electronics magazine, this circuit has an adjustable activation time that depends on capacitor C1. The SCR may be a 106 series equivalent.
This circuit is from Motorola's Linear Interface ICs from 1993. The MC1723 is the equivalent of...
T This circuit produces an audible signal when someone touches the sensor, or even approaches. The...
We found this circuit in a 1968 Electronics World. The transistors are from the era and...