If electric current flows in a coil, it experiences a force and moves. Spinning a magnet in a coil of wire generates electricity. Transformers change the size of alternating voltages.
Part ofPhysics (Single Science)Electricity, energy and waves
The ratio between the voltages in the coils of a transformer is the same as the ratio of the number of turns in the coils.
\(\frac{\text{primary~voltage}}{\text{secondary~voltage}} = \frac{\text{turns~on~primary}}{\text{turns~on~secondary}}\)
This can also be written as,
\(\frac{\text{V}_{1}}{{\text{V}_{2}}} = \frac{\text{N}_{1}}{{\text{N}_{2}}}\)
Step-up transformers have more turns on the secondary coil than they do on the primary coil.
Step-down transformers have fewer turns on the secondary coil than they do on the primary coil.
A transformer has 20 turns on the primary coil and 400 on the secondary coil. What is the output voltage if the input voltage is 500 V?
Therefore,
\(\frac{\text{V}_{2}}{{\text{V}_{1}}} = \frac{\text{N}_{2}}{{\text{N}_{1}}}\)
\(\frac{\text{V}_{2}}{500} = \frac{400}{20}\)
\(\text{V}_{2}= 500 \times \left (\frac{400}{20} \right )\)
\(\text{V}_{2} = {10,000{\text{ V}}}\)
