We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply need not be symmetrical. The FET in the feedback acts as an automatic gain control.
The A3906 integrated circuit from Allegro MicroSystems (www.allegro.com) consists of a single-step motor...
This circuit is used to connect an additional capacitor to a tuned circuit of a VFO. The circuit...
This touch sensor, found in an American documentation on transistors, has gained 8 million times...