Electromagnetic Induction

the process of generating a current in a circuit by passing a wire through a magnetic field

Electromotive Force the electrical potential increase measured in volts

EMF Formula EMF = BLv The velocity must be perpendicular to the magnetic field. If the velocity of the wire is not , the formula is EMF = BLv(sin  ) B = magnetic field L = length of the wire in the magnetic field v = velocity of the wire through the field

Generator a machine that uses mechanical energy to create electrical energy. The strength and direction of the induced current change as the armature rotates.

Max. Current from Generator I max when the v  of the wire is greatest through B P AC = ½ P AC,max = ½ P DC As you can see, voltage coming out of outlets varies.

Lenz's Law The direction of the induced current is such that the magnetic field resulting from the induced current opposes the change in the flux that caused the induced current. If a generator produces a small current, the opposing force will be small and vice versa. Lenz's law explains why using too small of a motor will burn it out.

When the motor is not moving, there is little back flow of current; therefore, there is much current flowing through the wire in the motor, and they overheat.

Self-inductance induced EMF produced in a coil by changing current. The faster one tries to change the current, the larger the opposing EMF, and the slower the current change.

Transformer a device used to increase or decrease the AC voltages. Step-up transformer- increases voltage Step-down transformer- decreases voltage