This commercial radio for the AM band was sold in Japan in the 1960s. The circuit has an IF of 455 kHz and is powered by batteries. The push-pull output gives a good audio power.
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...