Silent alarm (CB22471E)

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

MOSFETs SuperFET III (COM034E)
It can be obtained from Mouser Electronics new superFETs III from Fairchild for voltages of 700 V...
RS Flip Flop (CB8925E)
This circuit was found in a 1969s American documentation. With modern components, it can be used...
Changing the frequency of the LED blinking (CB24661E)
The figure shows how to change the frequency of a 5 V LED blinking. The capacitor can have other...