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# Inductor Electromagnetic field

Discussion in 'The Projects Forum' started by chrisw1990, Apr 4, 2012.

1. ### chrisw1990 Thread Starter Active Member

Oct 22, 2011
543
41
ok question:
how do you generate an electromagnetic field with an inductor?
im looking at using a PCB trace for the potential inductor, but i dont know how to simulate in LTSpice nor how the pcb trace would look..
any ideas?
Chris

2. ### crutschow Expert

Mar 14, 2008
23,124
6,858
A PCB trace wound in a spiral can provide a small inductance. Here's a calculator to help with that.

How much inductance do you need?

LTspice does not simulate magnetic fields, only inductors. You would need to calculate the inductance generated by the trace and put that into the simulation.

3. ### steveb Senior Member

Jul 3, 2008
2,431
469
Are you trying to generate a magnetic field, or an electromagnetic field? Normally, in circuit theory, we think of coils as generating a magnetic field only. However, as frequency goes up, the electric field becomes significant, and electromagnetic waves are eventually produced at significant levels.

If trying to create radiation, then the coil is typically called an antenna.

Assuming you are just trying to make a typical coil for magnetic fields only, then creating loops, such as the spiral suggested above, are a good way to make a pcb-trace inductor.

I don't know if SPICE provides the ability to calculate the inductance though. As far as I know, it does not and this is a field calculation that you can do independently. Once you know the inductance, you can simulate this inductor in SPICE.

4. ### chrisw1990 Thread Starter Active Member

Oct 22, 2011
543
41
im trying to create an inductance touch device.. iv had a look around but i cant find information, maybe im looking in the wrong places but google usually turns up something..

5. ### crutschow Expert

Mar 14, 2008
23,124
6,858
Why are you trying to use inductance? Most touch sensors use capacitance.

6. ### chrisw1990 Thread Starter Active Member

Oct 22, 2011
543
41
because inductance works through a metal front plate
or so i hear! and it also works with normal gloves too.