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Lenz law

I am doing a diagram to illustrate lenz law in a micro phone and a loud speaker.

I am in sure if my annotations are incorrect

Picture attached below
Here Is my diagram.
That is the loud speaker I forgot to add that
Original post by sly studies
That is the loud speaker I forgot to add that


The sketch looks nice though. Maybe You can add what material the diaphram is made of.
(edited 1 year ago)
My direction of electric field was incorrect I have altered it. Here is my up date

The questions is about illustrating lenz law. Because the magnet is fixed and the current comes from a voltage source it is confusing me.

Is the principle I have drawn correct ?
Original post by sly studies
My direction of electric field was incorrect I have altered it. Here is my up date

The questions is about illustrating lenz law. Because the magnet is fixed and the current comes from a voltage source it is confusing me.

Is the principle I have drawn correct ?

Some points:

When the alternative current changes the direction, the changed polarity of the source is the reason. Can be mentioned in my opinion.

A changed direction of the current leads to a changing direction of the magnetic field.

The force of the electromagnetic field works on the moving coil. It is attracted and repelled by it according to the direction of the current and induced magnetic field. The moving coil is connected with the diaphram and thus moves it.
(edited 1 year ago)
Original post by Kallisto
Some points:

When the alternative current changes the direction, the changed polarity of the source is the reason. Can be mentioned in my opinion.

A changed direction of the current leads to a changing direction of the magnetic field.

The force of the electromagnetic field works on the moving coil. It is attracted and repelled by it according to the direction of the current and induced magnetic field. The moving coil is connected with the diaphram and thus moves it.


All good point I've re drawn my work this is just a rough sketch but covers the points you've discussed
I will draw them more clearer , but as you said this now shows the current going in both directions and the magnetic field changing. On the microphone on both examples I have wrote sound in . But the f/movement is in and out to show the coil and diaphragm moving.
Do these seem more correct


IMG_20230218_210756.jpgIMG_20230218_210748.jpg
(edited 1 year ago)
Original post by sly studies
All good point I've re drawn my work this is just a rough sketch but covers the points you've discussed
I will draw them more clearer , but as you said this now shows the current going in both directions and the magnetic field changing. On the microphone on both examples I have wrote sound in . But the f/movement is in and out to show the coil and diaphragm moving.
Do these seem more correct


IMG_20230218_210756.jpgIMG_20230218_210748.jpg


Okay, the changing direction of the alternative current was sketched now. But what about the changing direction of the magnetic field around the coil? I see no difference there.
Original post by Kallisto
Okay, the changing direction of the alternative current was sketched now. But what about the changing direction of the magnetic field around the coil? I see no difference there.


The arrow that is opposing I says b in for induced magnetic field , I can draw the the direction on the sketch if that's not clear enough
Original post by sly studies
The arrow that is opposing I says b in for induced magnetic field , I can draw the the direction on the sketch if that's not clear enough

Sorry this has dragged on so long I now see what your saying I haven't shown the direction of the Field around the coils, if I add the arrows as shown in this picture, is the Bin/back EMf needed or is that a given.
Not sure if back EMf is the correct wording the point I am trying to make is that there is a force opposing the current
Original post by sly studies
Sorry this has dragged on so long I now see what your saying I haven't shown the direction of the Field around the coils, if I add the arrows as shown in this picture, is the Bin/back EMf needed or is that a given.
Not sure if back EMf is the correct wording the point I am trying to make is that there is a force opposing the current


At least you have drawn the opposite directions of induced magnetic field, but I see just one direction for the flow of the alternative current this time.
Original post by sly studies
Sorry this has dragged on so long I now see what your saying I haven't shown the direction of the Field around the coils, if I add the arrows as shown in this picture, is the Bin/back EMf needed or is that a given.
Not sure if back EMf is the correct wording the point I am trying to make is that there is a force opposing the current

Was this your final drawing?
Reply 12
Original post by thomas0611
Was this your final drawing?

no these where rough sketches while i tried to understand the direction of current and the induced current and how that effected the microphone i have much neater sketches i submitted with a key and colour coding.

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