This circuit was found in a 1967 Electronics World. Transistor Q1 can be a TIP321 and Q2 can be a BC558. The indicator lamp is optional.
This Mullard circuit was found in a 1969 documentation. It uses complementary transistors on the output and...
This circuit was found in an American documentation from 1968. The configuration can be adapted to...
We found this configuration in the Linear Applications Handbook of the National Semiconductor of...