We found this circuit in documentation from the 1980s. The transformer is of the low voltage type with a 1: 3 turn ratio and the transistors can be of general-purpose types.
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...