Transformers
A transformer is an electrical device used to change electrical potential.
Operation
- When current is supplied to the primary coil, a magnetic field is created.
- The magnetic field lines are then conducted along the iron core inducing a current in the secondary coil (Lenz's law)
- Note: there must be relative motion between the conductor and the field to sustain and induce current in the secondary coil
- The current in the primary coil is now reversed (since transformers are for alternating current), collapsing the initial magnetic field and creating a second one in the opposite direction. This gives the required relative motion, and the current in the secondary current is sustained.
The relationship between voltage and windings is given by:
Equation
Note that transformers are