Ideal Transformers (no load)
The primary circuit is just an AC voltage source in series with an inductor. The change in flux produced in each turn is given by:
- The change in flux per turn in the secondary coil is the same as the change in flux per turn in the primary coil (ideal case). The induced voltage appearing across the secondary coil is given by:
- Therefore,
- N2 > N1 ̃ secondary V2 is larger than primary V1 (step-up)
- N1 > N2 ̃ secondary V2 is smaller than primary V1 (step-down)
- Note: “no load” means no current in secondary. The primary current, termed “the magnetizing current” is small!