electricity

• what is current?

  flow of electric charge

  • charge = current x time (Q=IT)
• what is resistance?

  potential difference = current x resistance (V=IR)
• resistance depends on:

  • strength of components
  • other components causing resistance
  • length and diameter of wire
• Light dependant resistor:

  • the higher the light intensity the lower the resistance
• thermistor:

  • temperature dependant resistor
  • the higher the temperature the lower the resistance
• series circuits:

  • total potential difference is the sum of all potential difference in a circuit
  • current is the same everywhere
  • total resistance is the sum of all resistances in the circuit
• parallel circuits:

  • potential difference is the same everywhere
  • total current is the sum of all current in the circuit
  • current splits at junctions
  • if 2 resistors are in parallel the total resistance is less than the smallest resistor