Title: Questions about the flow of energy around an Inductor Coil.

[ToddB66]

Greetings !

I am using the Velleman K7102 build-it-yourself Metal Detector kit pictured below to make a Pinpointer. I will be mounting the completed kit inside a plastic electrical box w/plain cover and attaching a PVC plastic tube housing with end-caps to the side of the box. This tube will have the ferrite rod with copper wire coils mounted inside the front end and the tube will extend about 6" beyond the front end of the enclosure box.

The coil wire that came with the kit has the normal redish-colored varnish-like coating. I assume this coating does not inhibit the flow of magnetic lines of force to any noticeable degree. Therefore, since the coil wires will need to be extended alongside the coils (inside the plastic tube) and routed through holes to the connection points on the circuit board, I'm wondering if these connection wire leads laying so close to the coils will cause any disruption of the pinpointer signals. Would it be best to apply a thin coat of liquid-rubber just to these leads ?

Also, is the L1(120T) the transmit coil and the L2(40T) the receive coil ? If this is correct, then should I insert the ferrite rod into the PVC tube so that the L1(120T) coil
is at the front end of the tube, or does it make any difference to the function of the pinpointer ?

I'm just curious........where do the lines of electromagnetic force that flow into the ferrite core-rod end up going ?

Thanks for your help with these questions !

ToddB66

[Carl-NC]

Insulation has no effect on the magnetic field, and the wires may be laid against the windings any way you like. You may want to coat the windings to hold them tightly as movement might cause falsing. Probably L1 is the RX, you can test the response from each end of the ferrite rod to see if there is a difference. The magnetic field is focused through the ferrite core, then wraps around the outside of the windings.

[ToddB66]

Title: Questions about the flow of energy around an Inductor Coil.

Insulation has no effect on the magnetic field, and the wires may be laid against the windings any way you like. You may want to coat the windings to hold them tightly as movement might cause falsing. Probably L1 is the RX, you can test the response from each end of the ferrite rod to see if there is a difference. The magnetic field is focused through the ferrite core, then wraps around the outside of the windings.

Dear Carl-NC ..........Thanks for your above reply. Very helpful and thorough !

ToddB66