This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is suitable for detecting explosions, distant echoes and seismic vibrations.
This high input impedance circuit was found in American documentation from the 1980s. The power...
This circuit shows on the screen of an oscilloscope two signals alternately at a frequency that depends...
This circuit transmits the signal taken from a telephone line to a receiver placed nearby (up to a...