This circuit for old flashes with xenon lamps was found in a Radio Electronics magazine from June 1966. The sensor is a photoelectric cell from the time. Power is supplied by a 9 V battery.
Modulated signals up to a few megahertz can be detected with the circuit shown in the figure,...
We found this preamp circuit with tone control for bass and guitar in a 1987 documentation....
This circuit was found in an English publication. The components are current, and the transformer must be...