Current Electricity

• Current 


  It is the flow of electric charge in a conductor
• A circuit is a complete circular path or loop where electricity flows through.
• Conventional Current flow


  It is the flow from positive terminal to negative terminal
• Electron Flow


  It is the actual direction in which electron flow in a circuit
• Formula for Current

  I=Q/t
• One ampere is equivalent to one coulomb per second
• What is the standard unit for current

  Ampere
• Who is the father of electromagnetism?

  Andre-Marie Ampere
• Resistance (R)


  It is the property of a material or component that opposes the flow of electrical current
• Resistor


  It is used to limit the flow of electrical current in a circuit
• What are the factors that affecting the resistance of a conductor?

  The nature of the material, The length of the material, The cross-sectional area of the material
• Resistivity of common conductors

  • Silver: 1.59 x 10-8 Ω m
  • Copper: 1.68 x 10-8 Ω m
  • Gold: 2.44 x 10-8 Ω m
  • Aluminum: 2.65 x 10-8 Ω m
• Conductivity


  It is a physical property of a conductor that affects its ability to carry energy.
• Resistivity


  measures of the resistance of a given size of a specific material to electrical conduction.
• The length of the material

  the longer the conductor the greater its resistance
• The cross-sectional area (A) of the material

  The thicker the conductor the less its resistance
• For conductors, increase in temperature means increase in resistance
• Formula for resistance temperature

  R2=R1[1+a(T2-T1)]
• What is (a) stands for?

  Temperature coefficient
• He was a German physicist and mathematician

  Goerg Simon Ohm
• Ohm's law


  This law states that the current through a conductor between two points is directly proportional to the voltage across two points
• Formula for Ohm's law

  I= V/R
• Ohmic


  a material that follows ohms law
• Non-ohmic


  Does not follow ohms law
• Electromotive force


  It is the energy per unit charge supplied by a source of electron power. It is also represent the maximum potential difference.
• Electrical Energy


  It is the energy transferred of consumed by an electrical circuit or device over period of time
• Power


  It is the rate at which electrical energy transferred within a circuit per unit time
• Formula for power

  P= W/t
• Voltameter


  It is an instrument that measures the difference in electrical potential between two points
• Ammeter 


  It is used to measure the electric current in a circuit
• Two types of Voltameter

  Digital and Analog
• Analog Voltameter


  It moves a pointer across a scale on proportion to the circuit's voltage
• Digital Voltameter


  It measures an unknown input voltage