Loudspeakers and Galvanometers (1 Viewer)

[swimchick]

hey,

I am having trouble understanding the motor effect in both a loudspeaker and a galvanometer .
- Does the coil in a loudspeaker become an electromagnet?
- What is the direction of the force on the coil in a loudspeaker?
- Which ways does the coil move in a galvanometer? ie what direction is the force on the coil?
- Does the coil in a galvanometer become a electromagnet?

thanx:wave:

 

[+:: $i[Q]u3 ::+]

Q1 and 4:

It doesnt matter. Electromagnets don't come into this.
When the wires in the coil have electricity running through them, due to motor effect they experience a force.
In the galvanometer, the forces add to create a torque. The needle rotates and gives an indication of the size (and direction) of the current.
In the loudspeaker, the force causes the attached paper cone to oscillate (move back and forth) to create sound waves in the air.

Q2 and 3:

The direction of movement depends on the direction of the current. (Use right hand rule).
For a DC galvanometer, it will move in one direction.
However, with a loudspeaker, the current will oscillate so the direction of the force will continually change. This makes the paper cone vibrate back and forth etc..

You should also know that the magnitude of movement depends on the size of the current.

Hope that helps.

 

[swimchick]

Thanks i get it now.