Answer the following question given this paragraph: Electric substations have several functions. Many substations distribute electricity from a few high-voltage lines to several lower-voltage lines. They have electric transformers, which use electromagnetic induction to change the voltage of the current. Some transformers increase the voltage; others decrease the voltage. In the Figure below , you can see how both types of transformers are used in an electrical grid. Q: Electric substations have what devices, which use electromagnetic induction to increase or decrease the voltage of the current? Choices: - transistors - generators - tubes - transformers A:
A:
transformers