And if it has fewer loops than the primary coil, so it decreases the voltage, that's a step-down transformer.

如果它的回路比初级线圈少，那么它会降低电压，那就是降压变压器。

As the electricity in power lines travels from the power plant to your house, it goes through lots of step-up and step-down transformers.

当电力线中的电力从发电厂传输到您的房屋时，它会通过许多升压和降压变压器。