This circuit is from Dutch documentation from 1967. The circuit works with a component of the time, the BRY39, which is uncommon today.
This circuit is from 1977 documentation, and high current equivalent transistor must be used. The...
This circuit was found in a 1965 Electronics Design. The configuration can be applied to current...
This circuit was obtained in an 80's documentation, making use of a 3-terminal regulator of the...