which forms part of a colpits oscillator circuit to determine different types of metal as they pass through the coil at a fixed speed. By analyzing the frequency and amplitude shift as the object passes through the coil I am able to compare these to my known control values and identify the material.
The coil itself is coreless - it is wound on a plastic former without any metallic content.
I am quite new to electro magnetics / coils and fields etc... so have a couple of question that I am helping someone could advise me further on.
1) What would happen if i replaced my plastic former / core with a stainless steel one? What would this do to the field, I am guess it would reduce it but would it also change its shape?
2) What would happen if I introduced a large piece of stainless steel into the proximity of the coil (think mounting bracket etc..) how would this effect the field strength and shape?
Is there a good reference source for this subject?
many thanks in advance!