Robotics 2: LDR, Lesson 2, PDF

ROBOTICS 2 LESSON 2 : LIGHT DEPENDENT RESISTOR SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY TARGET OUTCOMES : At the end of the discussion, the students should be able to: Define what is Light Dependent Resistor Identify the working principle of LD...

ROBOTICS 2 LESSON 2 : LIGHT DEPENDENT RESISTOR SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY TARGET OUTCOMES : At the end of the discussion, the students should be able to: Define what is Light Dependent Resistor Identify the working principle of LDR and their characteristics. Create Projects that use LDR. SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY LIGHT DEPENDENT RESISTOR A light dependent resistor (LDR) or a photo resistor or photocell is a light controlled variable resistor. Its resistance changes with Light intensity that falls on it. SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY LIGHT DEPENDENT RESISTOR They are made up of semiconductor materials having high resistance. Photocells or LDR are non-liner devices. Their sensitivity varies with the wavelength of light incident on them. Some photocells might not at all responses to certain range of wavelength. SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY LIGHT DEPENDENT RESISTOR Light Dependent Resistor can be found in various devices like Automatic Street lights, Camera lights sensors and even Solar Panels. They enable automatic light detection and are crucial for energy saving applications. SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY CHARACTERISTICS OF LDR Photo Conductivity; As the intensity of the light increases, the resistance decreases. When a light dependent resistor is kept in dark, its resistance is very high. This resistance called as dark resistance. It can be as high as 1012 Ohms. SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY ADVANTAG ES LDR are cheap are readily available in many sizes and shapes. They need very small power and voltage for its operation. DISADVANTAG ES Highly inaccurate with a response time of about ten or hundereds of milliseconds SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY APPLICATIONS OF LDR Light Sensors : The LED lights up when the intensity of the light reaching the LDR resistor is sufficient. Example : Automatic Energy light. Fire Alarm : the alarm works by sensing the smoke produced during fire. When the is no smoke the light from the bulb will be directly falling on the LDR. Automatic street light : It automatically switches ON when the night falls and turns OFF when sun rises. SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY LDR PINOUTS SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY ACTIVITY 2 : LIGHT DEPENDENT RESISTOR SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY TARGET OUTCOMES : At the end of the discussion, the students should be able to: Build and key in the code based on the circuit diagram. SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY ACTIVITY 2 : LIGHT DEPENDENT RESISTOR MATERIALS SENIOR HIGH SCHOOL - MAIN CAMPUS LICEO DE CAGAYAN UNIVERSITY ACTIVITY 2 : LIGHT DEPENDENT RESISTOR