High Power Alarm (CB20475E)

We found this circuit in a Popular Electronics from the 90's. The circuit uses three SCRs to trigger the loads.

Overtone Oscillator (CB24030E)
This oscillator for the fifth overtone of a crystal was found in a Radio Electronics magazine from...
Complementary Photo Trigger (CB14660E)
This configuration uses complementary transistors, one of which is the phototransistor. The other...
Astable (CB15439E)
The circuit shown in the figure generates a rectangular signal whose frequency depends on C1. For...