c) Fixed resistors/lamps

ci) I-V characteristics of resistor, filament lamp, thermistor, diode, and light-emitting diode (LED)

fixed resistor (regardless of the polarity)

• current → directly proportional to potential difference

  • ohmic conductor

• resistance = constant

filament lamp (regardless of the polarity)

• current → not directly proportional to potential difference

  • non-ohmic conductor

• resistance = increasing

  • more electrons

  • more collisions with positive ions

  • electrons and positive ions have more kinetic energy

  • higher temperature