P2

• Switch

  —

  
• Cell

  —

  
• Battery

  —

  
• Diode

  —

  
• Resistor

  —

  
• Variable Resistor

  —

  
• Light Emitting Diode

  —

  
• Bulb

  —

  
• Fuse

  —

  
• Voltmeter

  —

  
• Ammeter

  —

  
• Thermistor

  —

  
• Light Dependent Resistor

  —

  
• Voltage is the energy transferred per charge carrier.

  Voltage = Energy / charge carriers

  V = E / Q
• Current is the rate of flow of charge carriers through a circuit, measured in amps.

  Amps = charge carriers / second

  A = Q / T
• 1 Amp = 6 x 10 ^9 electrons per second
• Electrons have to push their way through the vibrating ions of the metal wire. This causes resistance.

  Resistance = Potential difference / Current

  R = V / I
• Resistance is directly proportional to the length of the wire
• In ohmic conductors, the current is directly proportional to the potential difference.

  
• When current is flowing in the inverse direction through a resistor, high resistance occurs.

  
• In non-ohmic conductors, when the voltage is close to 0, the current is directly proportional to the voltage. As the voltage increase, the temperature of the circuit increases and the resistance increases.

  
• Ohmic conductor

  
• Non ohmic conductor

  
• Diode

  —

  
• With Light dependent resistor, the resistance decreases as the light intensity increases.

  
• Parallel circuits consist of two or more loops of wire

  • The potential difference of each component is the same.
  • The total current of the circuit is split between each component. If each component is identical, the current will be split equally.
  • The total resistance in a parallel circuit is lower than the resistance of the lowest resistor. This is because more amps are being drawn.
• Series circuits consist of one loop of wire

  • The potential differences of the power supply is split between each component. If each component is identical, the potential ditterence will be split equally.
  • The total current is the some current through each component.
  • The total resistance of a series circuit is the sum of the resistors in the circuit.