This circuit can detect static charges or extremely low voltages. The circuit was found in ancient American documentation and makes use of a JFET. A BF245 which is a more modern transistor can be used.
This amplifier was taken from documentation from the 1960s. Transistors are germanium types from...
This configuration elaborated with common junction FETs has a characteristic like that of tunnel...
This unusual amplifier configuration is from 1986. The circuit has a high resting current given the...