This commercial transistor tester circuit (EICO 666) is from a Japanese publication from the 1960s. The switch selects the types of test with the switching of the terminals and the gain ranges.
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...