Energy flow and losses
AC source
Magnetic field
Secondary coil
Load
Useful output 92%, copper loss 5%, core loss 3%.
A transformer trades voltage for current through a changing magnetic field. Power is approximately conserved; real devices also lose energy as heat and leakage flux.
Ideal versus real
Vₛ / Vₚ = Nₛ / Nₚ
Iₛ / Iₚ ≈ Nₚ / Nₛ
The voltage ratio follows the turns ratio. Current changes in the opposite direction, while coupling and material losses reduce delivered power.
“Can you touch it?”
Do not touch. Energized or unknown electrical equipment can cause shock, burns, arc injury, or death. Use a qualified professional.
Knowledge check
Why does ordinary DC not continuously induce secondary voltage?