This circuit was obtained from the March 1994 Electronics Now magazine. The circuit uses a common transistor which can be a low noise type such as the BC549.
This circuit is from Mallory 1968 documentation. The circuit makes use of period components and...
The different aspect of this source is the use of a 12 V lamp as a current regulator together with a...
For those who have multimeters that do not test transistors, in the figure we have a circuit that...