🔋college physics i – introduction review

Transformer equation

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

The transformer equation relates the primary and secondary voltages of a transformer to the number of turns in their respective coils. It is given by $\frac{V_s}{V_p} = \frac{N_s}{N_p}$, where $V$ represents voltage and $N$ represents the number of turns.

5 Must Know Facts For Your Next Test

  1. The transformer equation is derived from Faraday's Law of Electromagnetic Induction.
  2. It assumes an ideal transformer with no energy losses.
  3. The ratio of the voltages is equal to the ratio of the number of turns in the primary and secondary coils.
  4. For step-up transformers, the secondary voltage is greater than the primary voltage ($N_s > N_p$).
  5. For step-down transformers, the secondary voltage is less than the primary voltage ($N_s < N_p$).

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