This circuit was found in an American documentation from the 70s. The operational amplifier is from that time. Modern equivalents can be used.
This circuit from March 1984 Radio Electronics is intended to allow the use of an oscilloscope to measure...
This circuit was obtained in an English publication of 1975. It is a circuit that stabilizes an...
This control circuit up to 1 kW was found in a 1967 RCA documentation. The components are from...