Transformers Flashcards
What is a transformer?
A transformer is an electrical device used to increase (step up) or decrease (step down) the voltage of an alternating current (A.C.) supply.
How does it work
It works on the principle of electromagnetic induction and consists of:
A primary coil (connected to the input voltage)
A secondary coil (connected to the output)
A soft iron core (to carry the magnetic field)
⚡ It only works with A.C., not D.C., because a changing magnetic field is required to induce voltage.
What is the principle behind how a transformer works
A transformer works by electromagnetic induction.
An alternating current (AC) in the primary coil creates a changing magnetic field in the iron core.
This changing field induces a voltage in the secondary coil.
The voltage depends on the number of turns in each coil
Why is A.C. used for transmitting electrical energy over long distances?
A.C. allows easy voltage transformation using transformers.
High voltage transmission reduces energy loss (less heat due to lower current).
Transformers step voltage up for transmission and step it down for safe use in homes.
What is the formula for an ideal transformer
Powerout(Pₒᵤₜ)=Powerin(Pᵢₙ)
Vp Ip = Vs Is
Where:
𝑉𝑝 𝐼𝑝= voltage and current in primary coil
𝑉𝑠 𝐼𝑠 = voltage and current in secondary coil
For ideal transformers, there’s no energy loss
