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.
This partial circuit that must be added to a preamplifier output transistor as in CB19186E...
This 4-competitor TTL speed game was obtained in a 1980s documentation, but can still be easily...
We find this circuit in an American publication of 1978. The integrated circuit is the CMOS 4013...