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Electricity Static, Currents, Circuits 1
Electricity
Static, Currents, Circuits
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Electrical Fields Is a force field that surrounds an electric
charge or group of chargesSimilar to force field that surrounds a mass
– gravitational field
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Electrical FieldsElectric field has magnitude and directionVector quantity represented with electric
field lines (out from positive, in to negative)
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Electricity that moves…
Current: The flow of electrons from one place to another.
Measured in amperes (amps)Kinetic energy
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There are 2 types of currents:
Direct Current (DC) – Where electrons flow in the same direction in a wire.
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There are 2 types of currents:
Alternating Current (AC) – electrons flow in different directions in a wire
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What is Resistance?
The opposition to the flow of an electric current, producing heat.
The greater the resistance, the less current gets through.
Good conductors have low resistance.
Measured in ohms.
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What Influences Resistance?
Material of wire – aluminum and copper have low resistance
Thickness – the thicker the wire the lower the resistance
Length – shorter wire has lower resistance
Temperature – lower temperature has lower resistance
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Electrical Potential Energy
Energy a charge has due to its location in an electric field
Just as GPE is the work required to lift object, EPE is work done to push charge against the electric field of something else that is charged.
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What is Voltage?
The measure of energy given to the charge flowing in a circuit.
The greater the voltage, the greater the force or “pressure” that drives the charge through the circuit.
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Difference b/t Volts and Amps
Example – you could say that…Amps measure how much water
comes out of a hose.Volts measure how hard the water
comes out of a hose.
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Ohm’s Law
Resistance = Voltage / Current
Ohms = Volts / Amps
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Practice with Ohm’s Law
Ohms Volts Amps
4 100 25
15 150 10
2 30 15
9 45 5
6 48 814
CircuitsComplete path for electrons to flow (circuit)
Battery and Light bulbElectrons flow from negative terminal to
positive terminal
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How can we control currents?
With circuits.Circuit: is a path for the flow of
electrons. We use wires.
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Parts of a Circuit:
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Circuits:
For electricity to flow a circuit must be closed:
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There are 2 types of circuits:
Series Circuit: the components are lined up along one path. If the circuit is broken, all components turn off.
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Series Circuit
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There are 2 types of circuits:
Parallel Circuit – there are several branching paths to the components. If the circuit is broken at any one branch, only the components on that branch will turn off.
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Parallel Circuit
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Parallel CircuitSeries Circuit
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Schematics of Circuits
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Equivalent Resistance
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Equivalent Resistance
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Conductors vs. Insulators
Conductors – material through which electric current flows easily.
Insulators – materials through which electric current cannot move.
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Examples
Conductors:MetalWater
Insulators:StyrofoamRubberPlasticPaper
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