Static ElectricityStatic Electricity

Electrical Charge:Electrical Charge:

Is a concentration of Is a concentration of electricityelectricity

Unlike ChargesUnlike Charges

Attract one anotherAttract one another

Like ChargesLike Charges

Repel one anotherRepel one another

Electric FieldsElectric Fields

The effect an electric charge has The effect an electric charge has on other charges in the space on other charges in the space

around it.around it.

Strength of Electric FieldStrength of Electric Field

Amount of charge that produces the Amount of charge that produces the field field

And the distance from the chargeAnd the distance from the charge

Static Electricity and Static Electricity and ChargingCharging

Static electricity: is the study of Static electricity: is the study of the behavior of electric charges, the behavior of electric charges,

including how charge is including how charge is transferred between objects.transferred between objects.

Charges can be TransferredCharges can be Transferred

FrictionFriction

ContactContact

InductionInduction

Charging by FrictionCharging by Friction

Transferring of electronsTransferring of electrons

Charging by ContactCharging by Contact

Charging by contact occurs when Charging by contact occurs when someone actually touches another someone actually touches another object and the electrons are then object and the electrons are then

transferred (Van de Graaf Generator)transferred (Van de Graaf Generator)

Charging By InductionCharging By Induction

A transfer of charge without A transfer of charge without contact between materials.contact between materials.

Static DischargeStatic Discharge

Occurs when a pathway through Occurs when a pathway through which charges can move forms which charges can move forms suddenly. An example would by suddenly. An example would by

lightning.lightning.

Electric Current & Ohm’s LawElectric Current & Ohm’s Law

Electric CurrentElectric Current

The rate at which charges flows The rate at which charges flows through the lamp or wires.through the lamp or wires.

Current:Current: is how much electric is how much electric charge flows past a pint in a circuit charge flows past a pint in a circuit during a given time.during a given time.

Current is measured in ampes.Current is measured in ampes.

Two Types of CurrentTwo Types of Current

Direct Current (DC)Direct Current (DC)

Alternating Current (AC)Alternating Current (AC)

Direct CurrentDirect Current

Charge flows in one directionCharge flows in one direction

An example would be a flashlight or An example would be a flashlight or most battery powered devices.most battery powered devices.

Alternating CurrentAlternating Current

Is a flow of electric charge that Is a flow of electric charge that regularly reverses its direction.regularly reverses its direction.

Electric current in your home and Electric current in your home and schools are like this.schools are like this.

Conductors and InsulatorsConductors and Insulators

Electrical ConductorElectrical Conductor

Electrical InsulatorElectrical Insulator

Electrical ConductorElectrical Conductor

Is a material through which charge Is a material through which charge can flow easilycan flow easily

For example: copper; silver; and For example: copper; silver; and most metalsmost metals

Electrical InsulatorElectrical Insulator

A material through which a charge A material through which a charge cannot flow through easily.cannot flow through easily.

For example: Wood; Plastic; rubber; For example: Wood; Plastic; rubber; and airand air

Resistance Resistance

Is the opposition to the flow of Is the opposition to the flow of charges in a material.charges in a material.

The S.I. unit of resistance is Ohm.The S.I. unit of resistance is Ohm.

A materials thickness, length, and A materials thickness, length, and temperature affect its resistance.temperature affect its resistance.

SuperconductorSuperconductor

Is a material that has almost zero Is a material that has almost zero resistance when it is cooled to low resistance when it is cooled to low temperatures.temperatures.

The best superconductor so far is The best superconductor so far is cooled to 138 K.cooled to 138 K.

VoltageVoltage

In order for charge to flow in a In order for charge to flow in a conducting wire, the wire must be conducting wire, the wire must be connected in a complete loop that connected in a complete loop that includes a source of electrical includes a source of electrical energy.energy.

VoltageVoltage

Potential Difference: Potential Difference: is the is the difference in electrical potential difference in electrical potential energy between two places in an energy between two places in an electrical field.electrical field.

It is measured in joules per coulomb, It is measured in joules per coulomb, or volts, it can also be known as or volts, it can also be known as voltagevoltage..

Voltage SourcesVoltage Sources

BatteriesBatteries

Solar CellsSolar Cells

GeneratorsGenerators

Voltage SourcesVoltage Sources

Battery: Battery: is a device that converts is a device that converts chemical energy to electrical energy.chemical energy to electrical energy.

Have terminals that can connect to Have terminals that can connect to wires in a circuit.wires in a circuit.

One terminal is positive and the One terminal is positive and the other is negative.other is negative.

Ohms LawOhms Law

Founded by German Scientist Georg Founded by German Scientist Georg Ohm. Ohm.

First determined how resistance and First determined how resistance and current affect voltage.current affect voltage.

Discovered that voltage is not the Discovered that voltage is not the same everywhere in a circuit.same everywhere in a circuit.

Hypothesized that resistance reduces Hypothesized that resistance reduces the voltage.the voltage.

Ohm’s LawOhm’s Law

Ohm’s Law: Ohm’s Law: the voltage (V) in a the voltage (V) in a circuit equals the product of the circuit equals the product of the current (I) and the resistance (R).current (I) and the resistance (R).

V = I x R or I = V/RV = I x R or I = V/R Increasing the voltage increases the Increasing the voltage increases the

current. Keeping the same voltage current. Keeping the same voltage and increasing the resistance and increasing the resistance decreases the current.decreases the current.

Circuit DiagramsCircuit Diagrams

Electric Circuit: A complete path through Electric Circuit: A complete path through which charge can flow.which charge can flow.

Ex. Wiring in a houseEx. Wiring in a house

Circuit diagrams use symbols to represent Circuit diagrams use symbols to represent parts of a circuit, including a source of parts of a circuit, including a source of electrical energy and devices that are run electrical energy and devices that are run by the electrical energy.by the electrical energy.

Circuit DiagramsCircuit Diagrams

Circuit diagrams shows one or more Circuit diagrams shows one or more complete paths in which a charge complete paths in which a charge can flow.can flow.

Series CircuitsSeries Circuits

Series Circuit: charge has only one Series Circuit: charge has only one path through which it can flow.path through which it can flow.

Ex. Christmas Tree LightsEx. Christmas Tree Lights

If one element stops functioning in a If one element stops functioning in a series circuit, none of the elements series circuit, none of the elements can operate.can operate.

Parallel CircuitsParallel Circuits

Parallel Circuit: is a electric circuit Parallel Circuit: is a electric circuit with two or more paths through with two or more paths through which charges can flow.which charges can flow.

If one element stops functioning in a If one element stops functioning in a parallel circuit, the rest of the parallel circuit, the rest of the elements still operate.elements still operate.

Power & Energy CalculationsPower & Energy Calculations

Electric Power: the rate at which electrical Electric Power: the rate at which electrical energy is converted to another form of energy is converted to another form of energy.energy.

The unit is Watt or joules per secondThe unit is Watt or joules per second

Power is often measured in KiloWatts.Power is often measured in KiloWatts. Electric power can be calculated by Electric power can be calculated by

multiplying voltage by currentmultiplying voltage by current

Power and Energy CalculationsPower and Energy Calculations

Electric PowerElectric Power

P (Watts) = I (Amps) x V (volts)P (Watts) = I (Amps) x V (volts)

Electrical EnergyElectrical Energy

E = P x tE = P x t

This equation is used to find the This equation is used to find the electrical energy used by an electrical energy used by an appliance.appliance.

Electrical SafetyElectrical Safety

Correct wiring, fuses, circuit Correct wiring, fuses, circuit breakers, insulation, and grounded breakers, insulation, and grounded plugs help make electrical energy plugs help make electrical energy safe to use.safe to use.

Home SafetyHome Safety

Fuses:Fuses: prevents current overload in prevents current overload in a circuit.a circuit.

Circuit Breakers:Circuit Breakers: is a switch that is a switch that opens when current in a circuit is too opens when current in a circuit is too high.high.

Personal SafetyPersonal Safety

Grounding: when the electric takes a Grounding: when the electric takes a shorter path to a wire which leads to shorter path to a wire which leads to the ground. This is a transfer of the ground. This is a transfer of excess charge through a conductor.excess charge through a conductor.

Electronic DevicesElectronic Devices

Electronic SignalsElectronic Signals Vacuum TubesVacuum Tubes SemiconductorsSemiconductors Solid-State ComponentsSolid-State Components Communications TechnologyCommunications Technology

Electronic SignalsElectronic Signals

Electronics:Electronics: the science of using the science of using electric current to process or electric current to process or transmit information.transmit information.

Electronic Signal: Electronic Signal: is information is information sent as patterns in the controlled sent as patterns in the controlled flow of electrons through a circuit.flow of electrons through a circuit.

Electronic SignalsElectronic Signals

Electronics conveys information with Electronics conveys information with electrical patterns called analog and electrical patterns called analog and digital signals.digital signals.

Analog Signal: Analog Signal: is a smoothly varying is a smoothly varying signal produced by continuously changing signal produced by continuously changing the voltage or current in a circuit.the voltage or current in a circuit.• Information is encoded in the strength or Information is encoded in the strength or

frequency of the analog signal.frequency of the analog signal.

Electronic SignalsElectronic Signals

Digital Signal: Digital Signal: encodes encodes information as a string of 1’s and 0’s.information as a string of 1’s and 0’s.

Digital Signal is like Morse Code, Digital Signal is like Morse Code, when the current is off it produces a when the current is off it produces a 0 and when it is on it produces a 1.0 and when it is on it produces a 1.

Digital is more reliable than analog.Digital is more reliable than analog.

Vacuum TubeVacuum Tube Controls the flow of electrons in early electronic Controls the flow of electrons in early electronic

devices.devices.

Vacuum tubes can change alternating Vacuum tubes can change alternating current into direct current, increase the current into direct current, increase the strength of a signal, or turn a current on or strength of a signal, or turn a current on or off.off.

Example: TV tubesExample: TV tubes

Problem: burn out frequently and need replaced. Problem: burn out frequently and need replaced. They are also too large for small devices.They are also too large for small devices.

SemiconductorsSemiconductors

Semiconductor: Semiconductor: is a crystalline solid is a crystalline solid that conducts current only under certain that conducts current only under certain conditions.conditions.• Made with silicon or germaniumMade with silicon or germanium• Two types of conductorsTwo types of conductors

N-type: current flows as electronsN-type: current flows as electrons P-type: current flows as positive charge.P-type: current flows as positive charge.

When the two conductors are joined electrons from When the two conductors are joined electrons from the n-type are attracted to the positive p-type the n-type are attracted to the positive p-type conductor.conductor.

Solid-State ComponentsSolid-State Components

Most modern electronic devices are Most modern electronic devices are controlled by solid-state components.controlled by solid-state components.

• DiodesDiodes

• TransistorsTransistors

• Integrated CircuitsIntegrated Circuits

DiodeDiode

Combines n-type conductor and p-Combines n-type conductor and p-type semiconductor.type semiconductor.

• Changes alternating current into direct Changes alternating current into direct current.current.

TransistorsTransistors

Has three layers of semiconductors. Has three layers of semiconductors. Current flowing through its center Current flowing through its center layer changes its resistance.layer changes its resistance.

• Can be used a switch, because the small Can be used a switch, because the small current can turn another current on or current can turn another current on or off.off.

• Can be used as an amplifierCan be used as an amplifier

Integrated CircuitsIntegrated Circuits

A thin slice of silicon that contains A thin slice of silicon that contains many solid-state components.many solid-state components.• Commonly known as chips or microchipsCommonly known as chips or microchips

• Used in pages, mobile phones, and Used in pages, mobile phones, and computers.computers.

Communications TechnologyCommunications Technology

Computer: programmable device Computer: programmable device that can store and process that can store and process information.information.• Communication devices use microchips Communication devices use microchips

to make them more portable, reliable, to make them more portable, reliable, and affordable.and affordable.