Using the 2N2646 this circuit was found in a Radio Electronics magazine from July 1968. The transistors are from the time and the lamp can be replaced by a high-power LED in a current version.
This circuit with junction field effect transistors was found in documentation from the 1980s. The...
This ultra-low noise circuit was found in the May 1990 issue of Radio Electronics magazine. The...
The configuration shown is from the 1994 Linear Applications Handbook, published by National...