Current swing in bridge amp

Can someone please confirm or modify the following, given a bridged audio amp outputting a sinewave to an inductive load.

1. Reading across the load, the _voltage_ will be seen to rise and fall as a positive value every full cycle.

1. However, the _current_ changes direction every half cycle, at the peak and trough of the sinewave.

For example, if two wires were arranged side-by-side so their EMF cancels, they would effectively see twice the signal frequency in terms of current flow.

IOW the cancellation frequency, being once in each direction, would be twice the conventional sinewave frequency.

Thank you for any comments or corrections.

Tim

No. How could that possibly be? Firstly it should be obvious that the voltage across the load must reverse if the current through it reverses, there will of course be some phase shift between them. Secondly, to get a doubleing of frequency you need to generate the second harmonic somehow, that means passing through some non linear element, an inductor is linear, so no way there either.

The voltage changes signs as often as the current, it might be they are not in phase, but of the same frequency, somehow you are imagining something else.

Perhaps I did not explain my thoughts well enough.

To simplify, let's say there are two bridge outputs each driving a separate length of wire. There is no reference to earth.

These wires are then laid side-by-side but in reverse directions, such that when the current is following one way in one, it will be moving oppositely in the other.

We then apply a 100Hz sinewave of the same phase to each, which, for the purpose of this discussion, can be said to cancel each other out.

So then, while the applied frequency is 100Hz, there are actually two _cancellations_ per cycle due to current reversal. One each corresponding to the peak and trough of the sinewave. Hence it occurs at 200Hz.

This is simply a thought experiment. I realize the effect is not objectifiable.

Tim

They do not cancel twice per cycle, they cancel continuously throughout the cycle. Zero is zero. If the cancellation is not perfect, then there is a residual that is a smaller (and possibly phase shifted) version of the original waves.