Circuits

• Resistance = potential difference/current
• Resistance is the measure of how difficult it is for current to flow.
• When resistance increases, current decreases
• The longer the wire, the greater resistance

  The thicker the wire, the higher resistance
• Parallel circuits:

  • Potential difference through each branch is the same as the potential difference across the battery.
  • There are multiple paths for current to flow.
• Series circuits:

  • Current is the same through each component
  • Resistance is the sum of individual resistors
• The voltage supplied by the battery is shared so potential difference across the components equals the battery voltage.
• The thicker the wire, the higher the resistance because there are more ions for the electrons to collide in.
• The hotter the wire the more resistance because there ions have more kinetic energy.
• Energy = power x time
• Power = energy/time
• Time = energy/power
• Voltage = energy/charge
• Charge = energy/voltage
• kW W

  x1000
• Ma to a

  Divide by 1000
• V = IR
• Current always flows from positive to negative