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 direct-coupled amplifier was found in Mullard's 1960s transistor manual. The transistors are...
This circuit is from an American documentation from 1975. However, the circuit is still current, since...
The purpose of this circuit is to allow common analog multimeters to measure low resistances, on...