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.
April 2017 - Microchip's new 4-port KSZ8864 switches for VoIP, Games, Automotive Ethernet,...
This circuit that appears in similar versions on this site was found in a Popular Electronics from the...
This direct-coupled amplifier was found in Mullard's 1960s transistor manual. The transistors are...