What is an LDR?
An LDR, or Light Dependent Resistor, is a photosensitive device whose resistance varies with light intensity. It's often used in light-sensing circuits and can respond to a wide spectrum of light.
LDR's Working Principle
LDRs operate on the principle of photoconductivity. When light photons bombard the semiconductor material, they give energy to electrons, increasing conductivity and lowering resistance proportionally.
LDR Construction
An LDR consists of a high-resistance semiconductor material. It's usually made of cadmium sulfide (CdS), which reacts to light intensity by altering its electrical resistance.
LDR Characteristics
LDRs have a nonlinear response to light intensity, with a slow response time compared to photodiodes. Their sensitivity can be tailored for specific wavelengths by altering their composition.
Applications of LDRs
LDRs are used in devices like automatic street lights, alarm clocks, and burglar alarms. Their ability to detect light levels makes them suitable for non-critical light-sensing applications.
Advantages and Limitations
LDRs are inexpensive, simple to use, and durable. However, they're not suitable for precise light measurements or high-speed applications due to their slow response and limited spectral response.
LDRs in Modern Technology
Despite the rise of advanced photosensors, LDRs remain relevant in cost-sensitive applications. They're also used in educational settings to demonstrate basic principles of photoconductivity and electronics.
What does LDR stand for?
Light Dependent Resistor
Low Durable Resistor
Light Diverse Reactor
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