A generator. This can replace a battery as a power source. A generator converts movement energy into electrical energy like a turbine. A circuit diagram helps electrical engineers know what to build.

This circuit diagram shows the same circuit ... can be used to measure the potential difference produced by a cell or battery. The potential difference across a component can be measured by ...

The diagram illustrates the basic design ... that students can recognize and experience. Connect a circuit using wire, a 9-V battery, an LED, a resistor, and a microammeter to measure current.