Modulator Amplifier (V1574E)

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

200 mA LDO (CB1250E)
The circuit shown in the figure consists of a low voltage dropout (LDO) regulator for 200 mA using...
Varicap Variable Frequency Oscillator (CB4587E)
The great advantage of the circuit shown in the figure is that its frequency is controlled by a...
Electric Tool Torque Control (CB20794E)
Found in American documentation from the 1970s, this circuit can be designed based on a modern SCR,...