This filter, found in an old manual, has characteristics of reduced overvoltage given by the graph next to the diagram. Formulas for component calculations are given next to the diagram.
This circuit triggers an alarm when the mains power is cut off. The circuit was found in the July...
This acutely tuned circuit was found in American documentation from the 1960s. The transistors are germanium...
This small AM transmitter was found in American documentation from the 1980s. Transistor support...