transformer equation

Question

Ideal transformer relation between voltages and turns: Vp/Vs = ?

RankGuru · Accepted Answer

1. **Principle**: Transformers work on mutual induction. The same changing magnetic flux ($\Phi$) passes through every turn of both the primary and secondary coils.
2. **Faraday's Law Analysis**:
   - Primary Emf: $V_p = -N_p \frac{d\Phi}{dt}$
   - Secondary Emf: $V_s = -N_s \frac{d\Phi}{dt}$
3. **Ratio**: Dividing the two equations: $\frac{V_p}{V_s} = \frac{N_p}{N_s}$.
4. **Definitions**: $N_p/N_s$ is the turns ratio. If $N_s > N_p$, it's a **step-up** transformer. If $N_s < N_p$, it's a **step-down** transformer.

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transformer equation

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