P4.5.6 - The Transformer Flashcards
What is a transformer? [2]
a device used to change the size of an alternating voltage or current
What does a basic transformer consist of? [3]
- primary coil
- secondary coil
- soft iron core
Why is iron used? [1]
it is easily magnetised
What is a primary coil? [1]
the first coil
What is a secondary coil? [1]
the second coil
What is a step down transformer? [2]
- decreases the voltage of a power source
- secondary coil has fewer turns than primary coil (Ns < Np)
What is a step up transformer? [2]
- increases the voltage of a power source
- secondary coil has more turns than primary coil (Ns > Np)
What is the transformer equation? [2]
Vp / Vs = Np / Ns
What does a secondary voltage of a transformer depend on? [2]
- number of turns on the primary and secondary coils
- the primary voltage
What is the formula for electrical power? [1]
P = VI
What is the equation for an ideal transformer? [2]
VpIp = VsIs
How is electricity transmitted through power cables and why? [2]
- at a low current
- prevents dissipation of energy
What happens to the energy transfer if the current is lower? [1]
the more efficient energy transfer
Why is there heating in the wire? [1]
due to resistance
What is the equation for power loss? [2]
I^2R
