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Current Electricity
Static Electricity vs
Current Electricity
How are they different?
How are they the same?
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Static vs Current
Current Electricity Electrical charge move through a conductor (wire)○Flow is called current
●Like charges repel●Unlike charges attract
Static Electricity
Buildup of electric charge on the surface○The electrons
stay in one place
●Like charges repel●Unlike charges attract
Current Electricity: continuous flow of electrons in a closed circuit through a conductor (wire).
The following two conditions need to be met for current to occur:
1. Flow requires an energy source2. There needs to be a complete path for electrons to flow through.
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Components of Electrical Circuits Electrical Load: a device that converts electrical energy into another form of energy.
• Ex. light bulb, phone, TV, motor, etc.
Energy Source: a device that provides the circuit with energy to power the load. > It has positive and negative terminals> Ex. Battery, wall socket, etc.
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Switch: device that turns the circuit on or off by closing or opening the circuit, controls the flow of electrons. Wires: The metal material used to transfer the electrons (current) around the circuit, conductors.
Fuse: is an electrical safety device that will melt when too much current passes through it, creating an open circuit
State what the: source, load, wires, switch, and fuse is in the picture below. • If a component does not exist say so.
https://www.youtube.com/watch?v=kYwNj9uauJ4
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Law of Conservation: Electricity
The Law of Conservation of Energy states that energy is always conserved and is, therefore, never created or destroyed.
Electrical energy is transferred other types of energy.
Ex. Heat, Light, Kinetic Energy, etc.
THINK PAIR SHARE:
What is the law of conservation of energy and how does it relate to Current Electricity?
Circuit Diagrams
Circuit diagrams are diagrams with special symbols that show the components and connections in a circuit.
2 rules to follow when drawing circuit diagrams:1. Always use a ruler to draw straight lines for
the conducting wires
2. Make right angle corners so that your finished diagram is a rectangle
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Circuit Symbols
Draw a circuit diagram for this circuit.
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Draw a circuit diagram for Mrs Scully's floor lamp.
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Current, Resistance and Potential Difference
Electric Current: flow of electrons in a circuitResistance: resists flow of electrons, slows it downPotential Difference (Voltage): forces or push electrons forward
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Electric Current: measure of the amount of electrical charge that passes by a point in a circuit each second. Measuring Current: current is measured using an ammeter Unit: ampere (A)Types of Current:1. Direct current (DC) : flow in one direction
[ex. batteries]2. Alternating current (AC) : flow back and
forth at regular intervals [ex. wall socket]
Current
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Resistance: degree to which a substance opposes the flow of electric current through it (slows it down, resists).
Unit: ohms (Ω)
Resistor: resists the electrical current• Ex. Light bulbs: transfer current into light by
heat from the filament (resistor)
Resistance
Factors affecting Resistance:• Length• Longer the wires = more resistance
• Crosssectional Area (Width)• Bigger the crosssectional area = less resistance
• Material (Resistivity)• Some material have a better conductivity than others
• Temperature• Higher temperature = more resistance, conductivity decreases
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Potential Difference: Difference in electrical potential energy between two points in a circuit.
Measuring Voltage: voltmeter
Units: volts (V)
Potential Difference/Voltage
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UP NEXT:
Ohm's Law Calculations
V=IR
Voltage = Current x Resistancehttps://phet.colorado.edu/sims/html/resistanceinawire/latest/resistanceinawire_en.html
https://www.youtube.com/watch?v=kYwNj9uauJ4
Georg Ohm was the first to study the relationship between resistance ﴾R﴿, current ﴾I﴿ and voltage ﴾V﴿.
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• Resistance:> Unit: ohms> Symbol: Ω
• Current: > Unit: Amperes ﴾amps﴿> Symbol: A
• Voltage:> Unit: volts> Symbol: V
Symbols and Units
Voltage = Current x Resistance
• A 30V battery generates a current through a 15ohm resistor. How much current does the battery generate?
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A current of 4.0 A flows through a 40 ohm resistor. What is the battery’s voltage?
Current Voltage Resistance
Symbol
Unit
How to measure?
Recap
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Apr 2510:26 AM
Apr 242:50 PM
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Apr 2510:27 AM
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Apr 2510:28 AM
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