This circuit also appears elsewhere on this site, obtained from other sources. This is an 80's American schematic book. Instead the lamp can be used white high-brightness LEDs.
This circuit can turn-on (only) a load (relay or lamp) when S1 is pressed. The circuit can be used as...
We found this filter in the 1990 Motorola Linear Databook, but it can be implemented with other...
This 1969 Philips documentation circuit makes it possible to control an engine through the sound...