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.

Battery Charger (CB6394E)
We found this circuit in a 1968 Electronics World. The potentiometer should be set to trigger the SCR...
Variable Frequency Oscillator (VFO) (CB13123E)
The Variable Frequency Oscillator (VFO) or Variable Frequency Oscillator shown in the figure can...
Ceramic Pickup Amplifier TDA1010 (CB14722E)
This circuit provides a power per channel between 6 and 10 W depending on the load. The circuit is from...