Found in a 1968 EEE, this circuit uses transistors from that time. The output is 300 ns. Transistors can be replaced with modern equivalents.
This circuit is from a 1980s Motorola documentation. The circuit can be made with modern...
This well-known circuit triggers a relay when light striking the phototransistor is cut off. The...
This circuit generates a pulsed tone whose frequency depends on C2 and whose flashing depends on...