Photoresistor: meaning, definitions and examples
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photoresistor
[ ˈfoʊtoʊrɪˌzɜːr ]
electronic components
A photoresistor, also known as a light-dependent resistor (LDR), is a type of resistor whose resistance decreases with increasing incident light intensity. It is commonly used in various electronic devices and circuits for light sensing applications. The photoresistor operates on the principle that the resistance of the material changes in response to the amount of light it is exposed to.
Synonyms
LDR, light-dependent resistor
Examples of usage
- The photoresistor in the circuit adjusts the brightness of the LED based on surrounding light.
- In automatic streetlights, a photoresistor detects the onset of dusk.
- Photoresistors are used in cameras to adjust exposure levels.
- Some toys utilize photoresistors to respond to light.
- The alarm system triggers based on the light sensitivity of the photoresistor.
Etymology
The term 'photoresistor' is derived from two components: 'photo-' and 'resistor'. The prefix 'photo-' comes from the Greek word 'photos' meaning 'light', indicating the component's sensitivity to light levels. 'Resistor' refers to a component that resists the flow of electric current. The invention of photoresistors can be traced back to the mid-20th century, when scientists began experimenting with semiconductor materials that changed their electrical properties based on light exposure. Initially made from cadmium sulfide, these devices became popular for their ability to control electrical devices based on ambient light conditions. Over time, advancements in materials and technology have led to the development of faster and more sensitive photoresistors, making them essential in modern electronics.