This circuit was found in a Modern Transistor Workbook from 1965. The circuit sends signals from a small record player to a medium-wave radio placed nearby.
This old circuit excites lamps but can be modified to excite high-power LEDs or other loads...
We found this circuit in old documentation. Modern equivalent operational amplifiers can be used....
The purpose of this circuit is to regulate the output voltage of a source at 11.4 V or other...