Silent alarm (CB22471E)

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

Duty Cycle CMOS Astable (CB25330E)
We found this circuit in the March 1995 issue of Electronics Now magazine. The circuit has a...
Digital Infrared Link Shield (CB14684E)
This circuit uses a PNP transistor to modulate a low power infrared LED. Observe the polarity of...
Operational LC Oscillator (CB14838E)
The maximum frequency of this circuit depends on the operational, reaching a few hundred...