We found this circuit in a 1966 US documentation. It simulates a variable capacitor that can vary capacitance from 1,000 to 1. Transistors are general purpose types.
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
With this circuit the visually impaired can easily locate important places inside the house, such...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...