Infrared modulated transmitter (CB7247E)

This simple Philips circuit from the 1960s can use any general-purpose transistor. The signal is modulated at 2.7 kHz.

Differential amplifier (CB8990E)
This high input impedance circuit was found in American documentation from the 1980s. The power...
Dual trace for oscilloscope (CB5438E)
This circuit shows on the screen of an oscilloscope two signals alternately at a frequency that depends...
Listening Transmitter Via Power Grid (CB19325E)
This circuit transmits the signal taken from a telephone line to a receiver placed nearby (up to a...