We found this circuit in a documentation from the 90's. The coil has its characteristics given next to the diagram. Power is provided by a 9 V battery and a range of a few tens of meters.
This commercial medium and short-wave radio was manufactured in Japan in the 60s. The circuit has...
In the figure we have the way to use the LM3914 as a scale of bar LEDs or moving point. The...
Alternating taps on the pressure switch or sensor, cause the output to alternate the high and low...