This circuit is from a 1967 publication. The configuration holds true for modern transistors having a feedback across R2.
This 45 to 90 Hz hum elimination circuit was obtained from a 1980s documentation. The operational can...
The resistors R1 and R2 consist of 8 220 ohms x 2 W resistors connected in parallel. The...
Found in 90's Electronic Engineering this circuit can be used to measure phase angles between two...