Modulator Amplifier (V1574E)

This circuit is from a 1938 tube manual. Transformers are the critical components. Component values are given.

Infrared alarm receiver (CIR25209E)
This is the receiver from the previous alarm system. The circuit is from Radio Electronics, April...
Wireless battery charger (CB7267E)
The idea of this 1982 Experimenters Handbook circuit is to generate an RF signal in L2 that can be...
Simple Timer (MSB042E)
This circuit uses a capacitor to store energy. The capacitor is charged by closing S1 by a moment. Them,...