Study Notes
Transformers are devices used to change the voltage of an alternating current. They consist of two coils, the primary and secondary, wound around a soft-iron core.
- Transformer — an electrical device that changes the voltage of an alternating current. Example: Used to increase voltage for transmission and decrease it for safe use in homes.
- Step-up Transformer — increases the voltage from primary to secondary coil. Example: More turns on the secondary coil than the primary coil.
- Step-down Transformer — decreases the voltage from primary to secondary coil. Example: Fewer turns on the secondary coil than the primary coil.
- Efficiency — the condition where primary and secondary powers are equal. Example: Achieved by minimizing energy loss as heat.
Exam Tips
Key Definitions to Remember
- Transformer: an electrical device that changes the voltage of an alternating current.
- Step-up Transformer: increases voltage by having more turns on the secondary coil.
- Step-down Transformer: decreases voltage by having fewer turns on the secondary coil.
Common Confusions
- Confusing the roles of step-up and step-down transformers.
- Forgetting that transformers only work with alternating current, not direct current.
Typical Exam Questions
- What is a transformer? A device that changes the voltage of an alternating current.
- How does a step-up transformer work? It increases voltage by having more turns on the secondary coil.
- Why are transformers used in power transmission? To increase voltage for transmission and decrease it for safe use in homes.
What Examiners Usually Test
- Understanding of how transformers change voltage.
- The difference between step-up and step-down transformers.
- The role of transformers in electrical power transmission.