We found this circuit in the Linear Applications Handbook by National Semiconductor. The circuit is from 1994, but it can be made with more modern equivalent components.
This three-transistor circuit was found in Radio Electronics magazine from May 1969. The circuit is...
This beat frequency oscillator was found in a 1980s documentation. The original FET has a grounded...
With this circuit it is possible to make the selection of transistors and their test according to the...