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.

Alternator Voltage Regulator (CB6375E)
This circuit was found in an Electronic World of 1968. The circuit uses power transistors of the...
Pass Monitor (CB24892E)
This circuit is from Radio Electronics from March 1985. The circuit uses common components at the...
Digital amplifier 7400 (CB22432E)
This simple TTL digital amplifier uses NAND gates and a high impedance speaker. ...