Upon pressing the switch, the circuit generates a pulse whose duration depends on C. The transistors can be BC548 and the power can be between 1 and 6 V. The circuit is from a 1975 publication.
This proximity sensor circuit is from an 80's documentation. The used integrated circuits are...
Found in Popular Electronics from the 90s, this circuit triggers a bicolor LED to indicate whether a...
This reflex receiver was obtained from a 1963 documentation. The transistors are germanium, and...