Transformers

Transformers

#

A transformer is a static electrical device that steps voltage up or down in an AC circuit. Essential for the power grid.

Turns Ratio Formula

#

Step-up: \(N_2 > N_1\) → voltage increases. Step-down: \(N_2 < N_1\) → voltage decreases.

In an ideal transformer: \(V_1 \cdot I_1 = V_2 \cdot I_2\) (power is conserved).

In the Power Grid

#

1. Power plant generates at 10-25 kV
2. Step-up to 132-400 kV for transport (less losses!)
3. Step-down to 20 kV for distribution
4. Step-down to 230V for homes

📝 Why step up? Losses ∝ \(I^2\). Higher voltage → lower current → much less loss.

Efficiency

#

Small transformers: 95-97%. Large power transformers: 98-99.5%.

Conclusion

#

Without transformers, we couldn’t transport electricity over long distances. They are the pillar of the global power grid.