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 circuit can be used in bridge of sensitive measures. We found it in a documentation from the...
This interface was found in a Modern Electronics magazine from 1990. Although the circuit is...
Found in an old American documentation, this step has as input and output transformers coupling. Two...