153 Non Conservative Field

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The following diagrams summarise some interesting measurements, the outcome of which will probably surprise many people. (the red circle represents the region of alternating magnetic field)

Note that the voltmeters give different readings even though they are connected across the same two points.

This is due to the fact that the electric field generated by a changing magnetic field is fundamentally different from the so-called coulomb fields. In an non-coulomb field, where the field is not set up by electrical charges, the field is non-conservative. So moving a charge round one complete circuit actually does not return the charge to the original potential.

It is also useful to note that the “surprising” readings all have the voltmeter forming a loop that encloses the changing magnetic field itself.

152 Transformer

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The solenoid is the primary coil while the green wire is the secondary.

The video shows clearly how the secondary voltage is proportional to the number of turns in the secondary coil.

Since each additional turn increases the secondary voltage by about 0.064 V, and assuming that the primary coil is 230 V, the number seem to be suggest that the primary coil has about 3600 turns. It does not look like the primary coil has that many turns. So probably there is a lot of flux leakage.