A photocell, also known as a photoresistor or light-dependent resistor (LDR), is an electrical component that changes its resistance based on the amount of light it is exposed to. Photocells are widely used in various applications, from simple household devices like nightlights to more complex systems such as street lighting and security alarms.
Photocell sensors work like a timer switch in that they power light fixtures off and on automatically during a set “time”. They work a little bit differently though than timer switches because photocell sensors sense the natural light of the sun for controlling artificial light output from lighting fixtures. How Does A Photocell Sensor Work?
A: Yes, photocells can be used as part of a circuit that controls the brightness of LEDs. By connecting the photocell in series with a resistor and an LED, you can create a voltage divider circuit that varies the current flowing through the LED based on changes in light intensity.
A photocell sensor can also be used indoors in a space with windows. When there is no natural sunlight coming through a window, the sensor powers on your indoor lighting fixtures. Indoor photocell sensors increase and decrease the artificial light levels to save energy.
Some common types of photocells include Cadmium Sulphide (CdS) photocells, Photodiodes, Photoresistors, and Phototransistors. CdS photocells are sensitive to changes in light intensity and are suitable for detecting ambient light levels.
A: Photocells are specifically designed to detect light and changes in light intensity. They convert light energy into electrical energy through the photoelectric effect. As such, photocells are not capable of directly detecting other types of energy like sound or heat.