This is for the eddy current experts on this board.
In a sliding probe configuration (transmit-receive side by side coils), which coil is more likely to contain a ferrite core: the driver or the pick-up?
My explanation is two folded:
- if the driver contains the ferrite core the field would provide better penetration, but less spread, so less eddy current distribution and, therefore, a lower field to be picked-up by the receiver.
- if the pick-up contains the ferrite this will create a lower reluctance path for the field lines, which is a good thing, but it would increase the pick-up diameter, and, therefore lowering the resolution.