This circuit can be used as an answering password system in a store, office, or other location. The circuit is from Intersil using components of the time. The circuit is from the 80's.
It is like to the previous circuit with a lock that keeps the LED on at the end of the timer. The...
Found in old documentation, this circuit makes use of amplifiers of the time, uncommon today. Next...
This full-wave circuit was obtained in Motorola's 1974 unijunction transistors manual. The circuit...