We found this circuit in a 1985 documentation. The transformer is an old TV flyback that has an exposed part of the core, where 10 to 20 turns of common wire are wrapped.
This circuit monitors extra-low frequency (ELF) fields. We found it in an American documentation from the...
We can use any type of resistive transducer with central resistance in the range of 10 k ohms to 1...
This circuit controls two lamps so that when one increases in brightness the other decreases. The...