- A transformer is used to change the size of the alternating pd from generator to homes.
- A transformer only works on ac because a changing magnetic field is necessary to induce ac in the secondary coil.
- A transformer has an iron core unless it's a switch mode transformer with an a ferrite core.
- A switch mode transformer is lighter and smaller than an ordinary transformer. It operates at high frequency
A step up transformer makes the pd across the secondary coil greater than the pd across the primary coil. It's secondary coil has more turns than it's primary coil.
A step-down transformer makes the pd across the secondary coil less than the pd across the primary coil. It's secondary coil has less turns than it's primary coil.
- In a transformer, an alternating current is passed through the primary coil
- This coil creates an alternating magnetic field that passes through the secondary coil
- As a result, an alternating pd is induced in the coil
Primary pd, Vp/Secondary pd, Vs = np/ns (np/ns, number of primary/secondary turns)
For a 100% transformer, Vp x Ip = Vs x Is (I=current, V=potential difference)
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