Today we can call this circuit a baby monitor. It is a microphone amplifier found in a publication by Hugo Gernsback from 1960.
The circuit shown in the figure has a very high switching speed and can work with currents up to...
This amplifier, found in a 1980s documentation, should be powered by a symmetrical source. Modern...
This circuits shows how to use in operational amplifier as a basic voltmeter. Power supply must be...