Electricity: LDRs, Thermistors and LEDs

Electricity: LDRs, Thermistors and LEDs

Understanding LDRs (Light-Dependent Resistors)

  • LDRs are electrical components that use light to determine electrical resistance.
  • As light intensity on the LDR increases, the resistance decreased.
  • This property makes LDRs useful in devices that need to respond to light, such as automatic street lights or alarm sensors.

Studying Thermistors

  • Thermistors are temperature dependent resistors, the electrical resistance changes with temperature.
  • It has two types; positive temperature coefficient (PTC) thermistors and negative temperature coefficient (NTC) thermistors.
  • In NTC thermistors, as the temperature increases, the resistance decreases. It is used in temperature sensors, ovens and chargers.
  • PTC thermistors, on the other hand, show an increase in resistance as the temperature increases.

Basics of LEDs (Light Emitting Diodes)

  • An LED is a special type of diode that emits light when current flows through it.
  • The light it produces can be of different colours depending on the materials used to make the LED.
  • They are very efficient compared to traditional light bulbs, which is why they are used for many purposes, from indicator lights in electronic devices to lighting in studios and stadiums.
  • LEDs need a suitable resistor to limit the electrical current flowing through them to prevent damage.

Building Understanding on the Connection between LDRs, Thermistors and LEDs

  • A common connection among these three components is that they all alter their characteristics based on some form of external input (light for LDRs, heat for thermistors, and electrical current for LEDs).
  • For example, a combination of an LDR and an LED can be used to create a night light that turns on automatically when it gets dark.
  • Another common application is in temperature controlled fans using thermistors and LEDs, where the LED brightness could indicate the fan speed, which changes based on the temperature captured by the thermistor.
  • Understanding how these components work and how they can interact is key to grasping more complex electrical circuits and systems.

Remember, practical application of these concepts using real components often aids understanding. Always follow safety precautions when working with electrical equipment.