CIRCUITS AND CURRENT

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CIRCUITS AND CURRENT
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Recall Static Electricity

• The build up of stationary electric charges
  (positive and negative) on two different
  surfaces.
• Caused by the TRANSFER of electrons from one
  place to another.

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Current Electricity

• The continuous flow of electrons in a closed
  circuit.

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What is an Electric Circuit?

• A circuit is a pathway for electricity to flow
  made up of four basic components.

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Component 1 The Source

• Function
• Provides the circuit with electrical energy
  and a supply of current (electrons).

Schematic Diagram
one-celled battery
three-celled battery
AC power supply
AC
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Component 2 Conductors

• Function Wires/Wires Joined
• Provides a path for current to flow. In a
  perfect conductor no energy is lost. The current
  flows with no resistance.
• Function Ground Connection
• The ground allows electrons to flow to the ground
  or from the ground.

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Schematic Diagram
wire
wires joined
ground connection
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Component 3 Switch

• Function Open Switch
• An open switch prevents current from flowing
  in a circuit.
• Function Closed Switch
• A closed switch allows current to flow.
• Function Fuse/Circuit Breaker
• A fuse prevents a circuit from overloading
  with too much current by opening the circuit
  before it over heats.

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Schematic Diagram
open switch
closed switch
fuse/circuit breaker
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A fuse is basically a current limiting electrical
device, designed to destroy itself instead of the
equipment they are connected to.
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A circuit breaker is an electrical switch
designed to protect an electrical circuit from
damage caused by current overload or short
circuit. Its basic function is to interrupt the
current flow.
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Component 4 The Load

• Any device that needs electrical energy to
  function.
• The load is designed to take the electrical
  energy and converts it into the needed form of
  energy.

e.g. stove, fridge, toaster, light bulb
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Light Bulb

• Converts electrical energy into light energy.

Schematic Diagram
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Resistor

• A device added to a circuit to decrease the
  amount of current (electrons) flowing in the
  circuit per second.

Schematic Diagram
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A Motor

• Converts electrical energy in to mechanical or
  kinetic energy (movement).

M
Schematic Diagram
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Types of Energy

• Light Energy (e.g. light bulb)
• Heat Energy (e.g.stove, curling iron, toaster)
• Mechanical or Kinetic Energy - Movement
• (e.g. blender, ceiling fan)
• Sound Energy ( e.g. i-pod, radio)