Servo amplifier (T460E)

This circuit was found in a 1948 MIT publication. It uses two double triodes and has a high voltage supply. A 28V servo motor is used.

Transistor Hartley Oscillator (CB4576E)
This circuit consists of a single Hartley oscillator using a bipolar transistor that can generate...
Safety Light (CB4785E)
This circuit turns on your car's backlight when a vehicle coming from behind gets too close to it...
30 to 45 MHz Receiver (CB20514E)
Used by the police this receiver tuned to the low VHF band. The circuit is from a documentation from the...