Found in American documentation from the 90's, this JFET stage has an input impedance of 500 M ohms. Bipolar transistors are general purpose types and the FET supports an equivalent.
We found this circuit in the February 1989 issue of Radio Electronics magazine. The selectors are...
This circuit, which generates a linear sawtooth signal, can be used in a frequency-band...
This Audio System circuit was found in 1965 documentation. It is a 50 ohm line circuit with 22 dB...