• Introduction
• A Magnetic Personality
• A Powerful Discovery
• Around the Circuit
• What's a Watt and What It's Not
• NC GreenPower's Electrical Connection
• Download this article as a

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Around the circuit

To express itself as energy, electricity “flows” in a current through a circuit (from the word “circle”). A device that is connected to the circuit, such as a light bulb, draws current, while the current continues running in its circuit. Think of linking negatively charged electrons to positively charged ones. The link completes the circuit. When the link is closed the circuit is complete and electric current can flow. Because of their atomic structure, certain materials (called conductors)—such as metal and water—allow a better flow of electrons than others. Glass and rubber are not good conductors—they resist current—and are instead referred to as insulators.

The charge of electricity through conductors, such as the common copper wire found in building circuits, varies according to several factors. A commonly used analogy is a water hose: the charge of the water running through a hose used to power, say, a lawn sprinkler, is affected by the pressure of water from the pump, as well as the size and physical condition of the hose. In this analogy, the water pressure is similar to the electric pressure or force available from a power source, known as “voltage” and measured in volts. The amount of current flowing through the conductor—similar to the amount of water flowing through a hose—is measured in “amperes.” The power in an electric current that is available at the end—to run the sprinkler, in this example—is measured in “watts.”