This circuit divides the grid 60 Hz frequency to obtain 20 Hz to drive mechanical watches used at the time. The circuit is from a 1970 CQ magazine.
In the figure below we have the main configurations of power supplies with the most used...
This circuit is a high voltage source for a gas LASER. We found it in a documentation from the...
This integrated amplifier was used in televisions from the 70s, with good sensitivity...