The circuit shown in the figure below is from the 1993 Linear Technology Applications. The operational ones used are uncommon and the use of equivalents can be analyzed.
This three-transistor amplifier uses a JFET at the input to increase the input impedance. The...
This circuit, from a former publication of 1968 was originally designed for germanium transistors, but with the...
This amplifier for public address was found in English documentation from 1967. The transistors are from...