When the power is cut off, this circuit keeps the flashlight on for a while, allowing it to be located. The circuit is from a Radio Electronics from September 1992.
This bistable or flip-flop is triggered by a negative pulse applied to the collector of the...
This circuit is old, but it can be easily implemented with TIP42 transistors and a 6 + 6 V or 9 +...
This circuit is from the LM111 manual of the 1980s. The component no longer exists, but...