these lengths may be varied for ease of construction or to enhance performance also the number of turns on the transmit 28 and receive coil 26 may vary greatly the number of turns selected for each will depend on several factors such as the desired operating frequency the desired energy transfer and the desired amount of parasitic characteristics or characteristics such as resistance capacitance and inductance inherent in the winding itself fig4 shows the oscillating magnetic field 36 which has been generated by providing and oscillating emf to the transmit coil 28 this magnetic field oscillates at a frequency which matches the oscillation applied to the leads 22 and 34 of the transmit coil 28 placed in front of the sensor assembly 20 or in sensing proximity is the target material 40 which may be made of conductive or nonconductive matter or a compound of materials this matter or compound may be solid liquid or gas as the sensor assembly 20 is capable of discerning characteristics for all of these states for the sake of this explanation however we will assume that this target material 40 is solid within or on the target material 40 is a discontinuity 38 which may be a flaw or a desired feature of either the same material of the target or different material this discontinuity may be present on the surface closest to the sensor within the target or on the side of the target farthest from the sensor assembly 20 fig5 is.