This circuit was found in documentation from the 1980s. The integrated circuit is from the time and the voltage depends on the desired power, and the component's datasheet should be consulted.
This circuit was obtained from a 1962 magazine. It can still be mounted to be powered from 6 V...
This electronic level or plumb indicator has two mercury switches as sensors. The indication is...
This inverting amplifier has a transistor output stage that can increase its current capacity. Higher...