This simple circuit with two transistors was found in a 1985 publication. The power can come from batteries or battery, as consumption is very low.
This circuit was obtained in a 1969 documentation. The circuit modulates both the emitter current and...
This source can supply currents up to 5 A and the transistors admit equivalents such as TIP32. The...
This circuit was obtained from an English magazine from 1980, but as it uses components that can...