http://www.ck12.org Chapter 5. Energy
FIGURE 5.194
Stepping Up or Stepping Down
Notice that coil P and coil S in theFigure5.194 have the same number of turns of wire. In this case, the voltages of
the primary and secondary currents are the same. Usually, the two coils of a transformer have different numbers of
turns. In that case, the voltages of the two currents are different.
- When coil S has more turns than coil P, the voltage in the secondary current is greater than the voltage in the
primary current (seeFigure5.195). This type of transformer is called a step-up transformer. That’s because it
steps up, or increases, the voltage.
FIGURE 5.195
- When coil S has fewer turns of wire than coil P, the voltage in the secondary current is less than the voltage in
the primary current (seeFigure5.196). This type of transformer is called a step-down transformer because it
steps down, or decreases, the voltage.