Sensing Circuits

• Sensing circuits


  Circuits used to turn on or increase the power to components depending on the conditions that they are in
• Sensing circuit used to operate a fan in a room

  1. Fixed resistor and fan connected in parallel

  2. Potential difference of power supply shared between thermistor and loop of fixed resistor and fan

  3. As room gets hotter, thermistor resistance decreases, less potential difference across it, more across fixed resistor and fan, making fan go faster
• Connecting component across variable resistor

  • Potential difference across component is high when variable resistor resistance is high
  • Greater potential difference across component, more energy it gets
• Connecting a bulb across an LDR

  • Bulb gets brighter as room gets darker