Chapter 10-Physics

• Circuit


  A pathway in which electricity can flow
• 3 essentials of a circuit


  • Power supply - provides energy
  • Path - carries current
  • Load - uses energy
• Electric current


  A measure of the amount of electrons passing a particular point in an electric circuit every second
• Unit of current


  Ampere (A) or amp
• When electrons move to the negative side


  They repel away
• In a wire, electrons are negatively charged


  They move towards the positive side of the battery
• Voltage


  The amount of energy that pushes electrons around
• Higher voltage


  Faster current
• Lower voltage


  Slower current
• Resistance


  The factor affecting the flow of electrons
• Tighter wire


  Slower current
• Wide wire


  Faster current
• Electricity is the movement of electrons
• A bolt of lightning is evidence that electricity moves
• Electricity


  A type of energy (potential energy - stored energy, kinetic energy - moving energy)
• Electrons orbit the nucleus in shells
• Conductors


  • Materials in which electricity (electrons) can easily flow
  • Metals are good for this purpose
• Insulators


  • Materials in which electricity (electrons) cannot easily flow
  • Glass, wood and rubber are good for this
  • Often used for safety purposes
• Series circuit


  A circuit where all the components are connected one after another, on one path
• If one part of the series circuit is faulty

  The whole thing will break down
• In a series circuit

  The voltage (V) will split depending on the amount of loads there are
• In a series circuit


  • The current (I) will stay the same all the way around
• Parallel circuit


  A circuit where each component is connected on a separate path
• In a parallel circuit


  • The voltage of all the loads stays the same
• In a parallel circuit

  • The current will split depending on how many paths there are
• Voltage


  The amount of energy that pushes electrons around a circuit
• Current


  The flow of electrons measured in the same direction
• In a series circuit, if one part is faulty the whole thing will break down
• In a parallel circuit, if one part is faulty the other parts will still work
• Ohm's law: Voltage = Current x Resistance
• Current


  Measured in amps (A) by an ammeter
• Voltage


  Measured in volts (V) by a voltmeter
• Measuring current


  Ammeter must always be connected in series
• Measuring voltage


  Voltmeter must always be connected in parallel
• Voltage is a measure of potential energy
• Voltage makes electrons move
• Current (I)


  Measure of the amount of electrons passing a certain point in a circuit every second
• Resistance (R)


  • How much a component opposes (kind of stops) the flow of current
  • Causes electrons to bump into each other
• Increasing or decreasing resistance


  1. Changing the width

  2. Changing the length

  3. Changing the material of wire
• Resistance


  • Measured in Ohms (Ω)
  • Use an ohmmeter