EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: tommys on May 03, 2023, 07:56:19 pm
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Hello everyone,
I have to design a small pcb coil for small metal particles absorption in liquids (oils). I have never done coil pcb design so I want to know what should I pay attention to? Can the inductor be routed on one side of the board for example? How to avoid possible coil heating, magnetic field deficiency (weakness)?
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The inductor can be routed on one side of the board or on both sides. However, using a copper trace for the coil can help to reduce the resistance and improve the performance of the coil. Overheating can cause the coil to lose its magnetic properties, which can reduce its performance. To avoid overheating, make sure that your coil has an appropriate current rating and that it is not exposed to high temperatures.The magnetic field generated by the coil should be strong enough to attract the metal particles, but not so strong that it interferes with other components in your circuit. You may need to experiment with different coil geometries to achieve the desired magnetic field strength.
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barshatriplee points out the problem with fringing flux spashing onto other parts of your circuit.
Its not too hard to creat very small inductances- a few uH and under.
I'd start with a track width that will carry your coil current without any significant heating and go from there.
There's handy tool here- webench.ti.com/wb5/LDC/#/spirals
Above low values of L they start to get inconvieniently big with corespondingly lower flux densities
To attract even very small metal particles you'll need a fairly high flux density I imagine.
Size and current handling might be too low for a pcb inductor.
I once layed out diagonal condcutors with pth pads on the ends on a bit of flex-pcb and rolled it into a tube.
I glued the edge and joined the turns by hand soldering through the pads.