This circuit is from an American 1967 documentation and can be implemented with modern equivalent transistors. The circuit serves as a Q multiplier.
Similar circuits can be found on this site. This is from an 80's American documentation. The...
To operate with high input voltages using a 3-terminal voltage regulator such as the LM340-15, we...
This simple multimeter takes advantage of the low cost common galvanometer of 200 uA or 1 mA and...