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Welcome Back Minions. Put books on the floor. Only note taking material is to be on your desk. Quick Review. Objectives. What is Ohm’s Law? What are the basic features of an electric circuit? How many paths can currents take in series and parallel circuits? - PowerPoint PPT Presentation

### Transcript of Welcome Back Minions

Welcome Back Minions

Welcome Back MinionsPut books on the floor.Only note taking material is to be on your desk.Quick Review

ObjectivesWhat is Ohms Law?What are the basic features of an electric circuit?How many paths can currents take in series and parallel circuits?How do you calculate electric power and the energy used by an appliance?Starting offUnderstand electric circuitsFirst understand the relationship between:CurrentVoltageResistance

Ohms LawOhms LawResistance is equal to the voltage divided by the current

Resistance = Voltage Current = V A

Ohms LawDifferent ways to figure this outRemember:Resistance = Ohms ()Voltage = Volts (V)Current = Amps (A)

Resistance = Voltage Current (or) =VACurrent = Voltage Resistance (or) A=VVoltage = Current Resistance (or) V=AExample of eachCircuit has a resistance of 30 ohms and a current of .06 amps. How many Volts are there?Voltage = Current Resistance (or) V=AV= A ()V= .06 (30)V= 1.81.8 voltsExample of eachIn a circuit there is a 0.5 Amp current in the bulb. The voltage across the bulb is 4 volts. What is the bulbs resistance?

Resistance = Voltage Current (or) =VA = V A= 4 0.5= 88 ohmsExample of eachA waffle iron is running on a voltage of 120 and the resistance is 10 ohms. What is the current?

Current = Voltage Resistance (or) A=VA= V A= 120 10A= 1212 ampsFeatures of a CircuitThree FeaturesCircuits have devices that are run by electrical energy.

A circuit has a source of electrical energy.

Electric circuits are connected by conducting wires.

Diagramming a Circuit

Series CircuitIn a series circuit, there is only one path for the current to take.

Series CircuitDisadvantageBreak in the circuit from a burned out bulb!Light bulbs are dim as opposed to just one alone.Each bulb is a resistor!

Parallel CircuitIn a parallel circuit, there are several paths for a current to take.

Parallel CircuitInteresting factWhen you add a branch to a parallel circuit the overall resistance decreases.But if a resistance decreases, the current increases.

What will happen?Questions about the diagram below

So farFormula for resistance:1) A=V2) V=A3) =VA

Resistance = Voltage Current (or) =VA

So farFormula for current:1) A=V2) V=A3) =VA

Current = Voltage Resistance (or) A=V

So farFormula for voltage:1) A=V2) V=A3) =VA

Voltage = Current Resistance (or) V=A

So farWhat kind of circuit is this?1) Parallel2) Magnetic3) Series

So farWhat kind of circuit is this?1) Parallel2) Magnetic3) Series

Electric PowerPowerThe rate at which energy is transformed from one form to another.Unit of power is the watt (W).

Calculating PowerPower = watts (W)Voltage = volts (V)Current = amps (I) The letter i?I = Intensity of the Current

Power = Voltage x CurrentW=VIExampleA household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb?Power = Voltage x CurrentPower = 120 x 0.5Power = 6060 watts or 60W

ReviewWhat is Ohms Law?

1) Resistance is equal to the voltage divided by the current.2) An Ohm cannot be created nor destroyed.3) A current seeks the path of least resistance

ReviewWhat are the basic features of an electric circuit?

1) Run by electrical energy, has an electrical source, and connected by insulating wires.2) Run by electrical energy, has an electrical source, and connected by conducting wires.3) Resistance = Ohms (); Voltage = Volts (V); Current = Amps (A)

ReviewHow many paths can currents take in series and parallel circuits?

1) Series provides several paths while parallel is one continuous circuit.2) Parallel and series are one continuous circuit.3) Series is one continuous circuit while a parallel provides several paths.

ReviewHow do you calculate electric power and the energy used by an appliance?

1) Power = Voltage Current2) Power = Voltage x Current3) Power = Current Resistance