This circuit retriggers when a new pulse arrives. It does this by discharging the capacitor. The circuit is from a documentation from the 80s. The transistor can be any general purpose one.
With this circuit, from an old operational datasheet, it is possible to measure the CMRR,...
Found in a Popular Electronics from the 90s, this circuit can be adapted to use LEDs. The power...
The circuits shown in the figure, that of an infrared video signal transmitter and receiver, were...