Transformer
Also known as: step-up transformer, step-down transformer
A device that changes the voltage of alternating current by using two coils wound around a shared iron core. Transformers make long-distance power transmission efficient by stepping voltage up (reducing current and heat losses).
💡 Intuition
A transformer trades voltage for current (or vice versa) — like a gear system trades speed for torque.
Core Idea
Transformers only work with AC — the changing current in the primary coil creates a changing magnetic flux that induces voltage in the secondary.
Formal View
🔬 Example
🎯 Why It Matters
Transformers make long-distance power transmission efficient by stepping voltage up (reducing current and heat losses).
⚠️ Common Confusion
A transformer doesn't create energy — if voltage goes up, current goes down proportionally (power is conserved).
💭 Hint When Stuck
When solving a transformer problem, first identify the primary and secondary coils and their turn counts N_p and N_s. Then use the turns ratio V_s/V_p = N_s/N_p to find the unknown voltage. If asked about current, apply power conservation: V_p I_p = V_s I_s (assuming an ideal transformer).
Related Concepts
Prerequisites
How Transformer Connects to Other Ideas
To understand transformer, you should first be comfortable with faradays law and generator.
Go Deeper
Frequently Asked Questions
What is Transformer in Physics?
A device that changes the voltage of alternating current by using two coils wound around a shared iron core.
Why is Transformer important?
Transformers make long-distance power transmission efficient by stepping voltage up (reducing current and heat losses).
What do students usually get wrong about Transformer?
A transformer doesn't create energy — if voltage goes up, current goes down proportionally (power is conserved).
What should I learn before Transformer?
Before studying Transformer, you should understand: faradays law, generator.