Circuit Devices

• Light-Dependent Resistor (LDR)


  A resistor that is dependent on the intensity of light
• LDR


  • In bright light, the resistance falls
  • In darkness, the resistance is highest
• This is the circuit symbol for a light-dependent resistor
• Light intensity


  Resistance in LDR
• Thermistor


  A temperature dependent resistor
• Thermistor


  • In hot conditions, the resistance drops
  • In cool conditions, the resistance goes up
• Applications of thermistors


  • Car engine temperature sensors
  • Electronic thermostats
• Temperature


  Resistance in thermistor