Modulator Amplifier (V1574E)

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

Negative Ion Generator (CB22480E)
This circuit generates a high negative voltage responsible to produce ions in a tip electrode. The circuit...
Sensitive Photo Relay (CB894E)
This photo-relay uses a Darlington stage to increase sensivity. Any photo-transistor can be used....
Speed control with timer (CB20790E)
This circuit for alternating current loads has a built-in timer. SCR2 is according to the motor...