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How can we help you?
1. What is a Photocell
“A photocell is a resistor that changes resistance depending on the amount of light incident on it. A photocell operates on semiconductor photoconductivity: the energy of photons hitting the semiconductor frees electrons to flow, decreasing the resistance.
An example photocell is the Advanced Photonix PDV-P5002, shown in Figure 21.2. In the dark, this photocell has a resistance of approximately 500 kΩ, and in bright light the resistance drops to approximately 10 kΩ. The PDV-P5002 is sensitive to light in the wavelengths 400-700 nm, approximately the same wavelengths the human eye is responsive to.Figure 21.2 shows a simple circuit illustrating how it can be used as an ambient light sensor feeding either a digital or an analog input to the PIC32.”
——Embedded Computing in C with the PIC32 Microcontroller
1. Photocell Products
It is precisely because of the characteristics of the photocell’s working principle that a new type of product is produced: photo controller. These products are mainly used in the field of outdoor lighting control, reducing energy resource consumption and costs, and extending the life of the luminaries.
1)Twist-Lock Photo Control (JL-202/JL-214/JL203)
The Twist-Lock photo controllers are applicable to control the street lighting, garden lighting, passage lighting and doorway lighting automatically in accordance with the ambient natural lighting level.
The JL-202 Photo controller is designed on the basis of thermal - bimetallic structure that provides time delay over 30 seconds to avoid Mis-operation due to spotlight or lightning during the night time. A temperature compensation system provides consistent performance regardless to the ambient temperature.
The JL-214 Photo Controller is designed with electronic circuits with sensor of phototransistor and a surge arrester (MOV) is provided. Its quicker response with time delay of 5-30 seconds offers easy-to-test feature. Especially, model JL-214B/224B has an omni-directional face-top sensor for customer applications per BS5972-1980. Further, a preset 5-30 seconds time-delay might avoid mis-operation due to spotlight or lightning during the night time.
The JL-203C Photo Controller designed with electronic circuit assisted thermal switch, with sensor of IR filtered photodiode and a surge arrester (MOV) is available. Its multi-volts feature expands the application of thermal switch which is powerful to carry high wattage lamp loadings, regardless the loading in incandescent, ballasted or e-ballasted. Besides, its time-delay feature might avoid mis-operation due to spotlight or lightning during the night time.
Application
2)Wire-in Photo Control
The Wire-in Photo Controls are applicable to control the Outdoor lighting, passage lighting and doorway lighting automatically in accordance with the ambient lighting level.
The JL-103 photoelectric switch has been listed by UL Inc and is comply with the Standard for Non-industrial Photoelectric Switches for Lighting Control UL773A.
The JL-104 Photo Control is designed on the basis of electrical heating structure that provides time delay over30 seconds to avoid redundant switching against spotlight or lightning during the night time. A temperature compensator system provides consistent performance regardless of the ambient temperature.
JL-104 has a gathered swivel with the sensor/switch body for convenient direction adjustment after installation. Additional swivel is also available for further adjustment.
The JL-118 Photoelectric Switch is designed on the basis of electrical heating structure that provides time delay over 30 seconds to avoid redundant switching against spotlight or lightning during the night time. A temperature compensator system provides consistent performance regardless of the ambient temperature.
JL-118 series is convenient direction adjustment after installation once an additional swivel is applied.
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