This 5.1 MHz circuit was found in a 1980s documentation. The frequency is given by the crystal and general purpose transistors can be used.
Using an operational amplifier with FET, this voltmeter has a high input resistance. The circuit has...
This circuit is from 1998 documentation. The coils consist of the number of turns indicated on...
We found this oscillator in a documentation for radio amateurs from the 1970s. The circuit can use...