This circuit was found in an American documentation from the 70s. The operational amplifier is from that time. Modern equivalents can be used.
The first circuit we present consists of a step-down DC / DC converter with input voltage from 2.5 to...
This source for 50 W amplifiers per channel was found in 1967 Delco documentation. Transistors are from...
This interesting circuit of an ancient American publication makes the pattern of an exclamation mark...