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.
We found this circuit in a 1976 FET documentation. The circuit can be used to oscillate at other...
This oscillator generates a 1 kHz signal, using an old germanium PNP transistor. The circuit was...
We found this circuit in a European publication from the 1980s. The circuit uses germanium...