13.1
What Is an Electric Circuit?
-electric circuit – a continuous path along which electrons flow that includes an energy source, a
load, conductors, and usually a switch
-only complete when the circuit is closed
-turning on a device closes the circuit
Parts of a Circuit
-every electric circuit requires an energy source, a load, and conductors
-load – an electrical device that converts electrical energy into another form of energy
-e.g. is a light bulb, hair dryer, mixer, TV, etc.
-switch – a control device that allows you to safely open or close a circuit
-basically turns the device on and off
-flashlight is an example of a simple circuit
Energy Sources
-energy source – a device that provides electrical energy in a circuit, such as a battery or an
electrical outlet
-often a battery
-electrons flow in one direction through a circuit and back to the battery
-some devices need more energy for longer periods of time and use electricity from a wall outlet
instead of a battery
-electrons flow back and forth between generating station and devices plugged into
outlets
-referred to as alternating current
Conductors
-in many circuits these are wires
-e.g. conducting wires in walls connect energy source to each outlet
-may be a piece of metal like in the flashlight
Load
-anything that requires electrical energy to work
e.g. toaster, TV, lamp, etc.
Switch
-switches close a circuit (turn a device on) or open a circuit (turn a device off)
-controls the flow of electrons in the circuit
Circuit Symbols and Circuit Diagrams
-circuit diagram – a way of drawing an electric circuit using standard symbols
-series circuit – a circuit in which two or more loads are connected one after another so that
electrons follow only one path
-parallel circuit – a circuit in which two or more loads are connected so that electrons can follow
more than one path