Silent alarm (CB22471E)

This circuit is from a Popular Electronics from 1992. The circuit powers an LED when triggered.

555 Linear Ramp Generator (CB24462E)
We have other similar setups on this site. This one is from September 1976 Radio Electronics. The...
24 V Power Control (CB839E)
This low voltage AC control uses a triac. Any TIC series triac can be used and this device must be...
540 mW amplifier (CB21801E)
Using germanium transistors, this amplifier provides a 540mW output power when powered by 9V. We...