This circuit was found in an American medical documentation from 1970. The circuit rejects the 60 Hz noise pickup and generates 2.5 Hz signals. Equivalent components can be tested.
Suggested by Harris in documentation from the 80s, this circuit uses components from that time. It...
This high-voltage regulator uses only two components. The resistor is a wound wire type with 1 W...
This circuit uses an impact sensor transistor called Pitran rare today. The circuit is from 1969...