This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is intend to receive MW station and the transistors are germanium types not easy to find today.
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...