9Electricity and Circuits PropertyUnits of MeasureVoltage (V)Current (I )Resistance (R)Power (P)Volts (V)Amps (A)Ohms (Ω)Watts (W)
10Electric CircuitsAn electric circuit is a network of electrical components (resistors, transmission lines, electrical sources, switches, etc.) that forms a closed loop and provides a path for electrical energy.Circuits have three basic parts:An energy source that converts non-electrical energy into electrical energy; examples are batteries and generators.An output device that uses electrical energy to do work; examples are motors, lamps, and displays.Materials to make a connection to allow electrical energy to flow; examples are wires and cables
11Examples of Symbols for Circuit Diagrams ComponentSymbolFunction of ComponentWireTo pass current from one part of a circuit to anotherWires joinedA ‘dot’ should be drawn to show where two wires join together.BatterySupplies electrical energy; the larger terminal is positive (+)Light Bulb and SocketConverts electrical energy to light energyResistorRestricts the flow of currentOn-Off SwitchAllows current to flow only when it is in the ‘on’ (closed) position+-
13Series CircuitsElectrical components connected in series are connected along a single path so the current only has one path to follow.If one component in a series circuit is disconnected or fails, the entire circuit is turned off.switchbatteryBulb AIn the circuit to the left, what would happen if Bulb B burned out?Bulb BIf Bulb B burned out there would be no way for the electrical energy to flow. Bulb A would not light.
14Parallel CircuitsElectrical components connected in parallel are connected so that the current has multiple paths that it can take.If one component in a parallel circuit is removed or fails, the other components will still have an intact path for current and will continue to work.batteryBulb ABulb BBulb C
15Review Activity – Circuits Answer the questions on the Review Sheet Review Activity – Circuits Answer the questions on the Review Sheet. After you have finished, your teacher will help you check your answers using this animation.Switch ASwitch BSwitch CSwitch DBulb ABulb BBulb CBulb DBatteries
16ResistorsA resistor is a component that restricts the flow of current.Resistance is measured in ohms. The symbol for the ohm is (omega).On a circuit diagram, resistors are represented by24