- Electronics Projects
- 1.5v to 220v AC simple inverter
- Build Simple AM Radio receiver at home
- Simple Uninterruptible Power Supply (UPS) Circuits
- Single Transistor Amplifier Circuit
- 3.7v Lithium Battery Level Indicator
- LED Chaser using transistors
- Electronics Projects for Beginners
- Simple Latch Circuit Using Transistors
- DC to AC Power Converter circuit feature working
- Fire Alarm Circuit using Transistor
- Two Transistor Amplifier
- Laser Security System
- Music Operating Dancing LEDs light
- Volts Booster Circuit Using Ferrite ore transformer
- Touch switch circuit using Transistor
- Two transistor FM transmitter project
- LED Flasher Using Timer IC 555
- DC Voltage Power Supply Using The LM317
- Electronic Mosquito Repellent Circuit
- Light Dimmer Circuit 1000 Watts Using BT139
- Non-Contact Voltage Detector by using transistor
- 4 volts simple inverter project: explanation
- Flashing Police Lights Circuit
- Light Dependent Resistor, its types and applications
- 100 watts inverter circuit working and applications
- Stereo Audio Amplifier 5W Circuit using TEA 2025 IC
- Small High Volts using 2Sc 1815 transistor
- Electronic Doorbell Circuit using a 555 and CD4017
- Touch On Touch Off Switch Circuit Using 555 timer
- LM386 Audio Amplifier Circuit
- IC 4440 Amplifier Circuit
- Neon Lamp Circuits Working and Application
- Low Power Audio Amplifier Using integrated circuit
- Voltage Regulator Circuits using Transistor and Zener Diode
- Water Level Indicator Circuit Using Transistor
- LED Chaser using CD4017 IC
- Motion Sensor Light Switch
- Melody Generator Using IC um66
- Water Level Indicator Using IC
- Led Light to 220v AC
- LiFi Data Transfer System, WiFi vs LiFi
- How to Connect a CAR Battery | Polarity Checker
- Voltage Level Indicator Circuit
- Security Alarm Using PIR Sensor
- Battery Level Indicator Using LM 3914
- Single Transistor FM Transmitter circuit
- Different types of Capacitor
- Light Emitting Diode (LED) Types of LEDs
- Different Types of Relays
- Piezo buzzer features equivalent
- Clap Switch : Circuit and Its Working
- Different Types of diode, working and features
- PC817 Optocoupler Pinout, Equivalent, Features and applications
Light Dependent Resistor, its types and applications
A Light Dependent Resistor is also known as a photoresistor, photoconductor, or photocell. LDR is one kind of resistor whose resistance different depending on the amount of light falling on its surface. When the light falls on the resistor, then the resistance modifies. These resistors are often used in many circuits where it is needed to sense the attendance of light.
These resistors have different types of functions and resistance. For example, when the LDR is in darkness, then it can be used to turn ON the light and used to turn OFF a light when it is in light. A common light-dependent resistor has a resistance in the darkness of 1M(Ohm) and in the light resistance of a pair of K (Ohm).Pin detail of Light Dependent Resistor(LDR).
Working of Light Dependent Resistor
This resistor operates on the principle of photoconductivity. It is nothing but, when the light falls on its surface, then the material conductivity lowers, and also the electrons in the valence band of the tool are excited to the conduction band. These photons in the eventuate light must have energy more than the band space of the semiconductor material. LDR manufactures the electrons to jump through the valence band to conduction.
These tools depend on the light, when light falls on the LDR then the resistance will be low, and grows in the dark. When an LDR is staying in a dark place, its resistance is high and, when the LDR is staying in the light its resistance will be low.
Types of Light Dependent Resistors (LDR)
There are two types of Light Dependent Resistors(LDR) are as follows:
Intrinsic Photo Resistors
These resistors are pure semiconductor tools such as silicon or germanium. When the light falls on the LDR, then the electrons obtain excited from the valence band to the conduction band and a number of charge carriers grow.
Extrinsic Photo Resistors
These tools are doped with pollution and this pollution makes a new energy band upon the valence band. These bands are filled with electrons. So this decreases the bandgap and a small quantity of energy is needed in moving them. These resistors are fundamentally used for long wavelengths.
Application of Light Dependent Resistor:
- Used in the security alarm.
- Used in the photosensitive relay.
- It is used in-camera light meters.
- The LDR is used in optical coding.
- The LDR is used in smoke detectors.
- Used in light-activated control circuits.
- The LDR is used in infrared astronomy.
- The LDR is also used in street light control circuits.
- Used in light failure alarm circuits and used in light meters.
- The Light Dependent Resistor (LDR) is used for automatic contrast and brightness control in television receivers.
