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Toroid Core Wire Wo...

Toroid Core Wire Would Inductor placement in PCB for Mutual Aid mode?  


Active Member
Joined: 2 months ago
Posts: 8
15/01/2020 3:40 am  
How we can place toroid core inductors two or more in parallel or series in a printed circuit board so that we get the benefit of mutual inductance to aid or deteriorate the overall inductance of the combined inductors?  Just placement thumb rules for approx calculation. I wish to get some help from you on how we can get the desired extra mileage by fine-tuning placement positions.   ( Keeping them far away to avoid mutual inductance is a known option). 
Is this a practical idea to get leakage flux back in use saving energy?

Jimmy Davis
Active Member
Joined: 3 months ago
Posts: 14
15/01/2020 4:55 am  
Hi ShellyLane, the advantage of toroidal coils as compared to other geometries like E-I-cores, etc. is that there is ideally no leakage flux at all. In reality, the leakage flux is limited to spatial dimensions of the same order of magnitude as that of the spatial irregularities of the winding (e. g. spacing between wires).
So, while it is not recommendable to place the input stage of an amplifier near the line transformer, I'm afraid that the effect of the spatial distribution of several toroidal inductors is negligible. You might take two identical toroidal coils (without PCB), connect one to an AC source (without overloading the coil), and connect the other to an AC voltage measuring device (multimeter or scope). Then move the coils relative to each other and observe the induced voltage in the second coil. I bet it will be far less than 1 % of the voltage at the first coil.