Mammoth Memory

Creating alternating current (AC)

We can create an alternating current from the mechanical movement of turning around a handle.

Producing an alternating current means the voltage produced alternately reverses from positive to negative polarity, producing a corresponding change in direction of current flow.

We can use Fleming's right-hand rule.

RIght = Induced (ie, electricity is created)

Flemings right hand rule

Fleming's right-hand rule shows us the direction of the current in the wire below.

Creating an A.C. Current

When the handle has been spun 180° you can see the direction of the current in the wires has reversed in relation to the two magnets.

Handle turned 180° while creating an A.C. current

For each turn of the handle, the galvanometer will show a complete movement from one side to the other and back again.

If you were to plot the voltage change through time for one complete revolution of the handle you would find the following:

Graph of voltage produced when creating an A.C. current

NOTE: Point `A` is where the wires within the magnetic field are vertically aligned. Point `B` is illustrated in the first diagram. Point `C` seen in the second diagram.

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