Dual triode receiver (T1591E)

Found in a 1949 Radio Electronics, this regenerative circuit has high-impedance headphone listening. Power supply not provided.

100 kHz Calibrator (CB5607E)
This circuit was obtained from Popular Electronics of the 1990s. The circuit uses common...
50 Ohm Line Drive Amplifier (CB4040E)
The circuit shown uses an operational transconductance amplifier such as the LM3900. Transistors...
Code Practice TTL Oscillator (CB4188E)
This simple Morse Code oscillator was found in a 1980s American documentation. The power supply...