Functional Devices Relays, Current Sensors, Power Supplies, Transformers, Enclosures, Wireless Devices at Controls Central


    Relays are crucial electrical components used to control and switch electrical circuits remotely. They operate as electromagnetic switches, responding to electrical signals to open or close the circuit, allowing current to flow or interrupting it. Relays play a vital role in various applications, providing a reliable means of controlling high-power circuits using low-power control signals. They are commonly used in industrial automation, HVAC systems, motor control, lighting control, and building management systems, enabling precise and efficient control over electrical processes. Relays come in various types, including electromechanical relays, solid-state relays, and reed relays, each suited for different applications based on their characteristics and performance.

    Schneider, Johnson Controls, MARS, and Johnson Controls are esteemed brands renowned for their expertise in manufacturing high-quality relays. Schneider Electric offers a comprehensive range of relays designed for industrial and commercial applications, ensuring reliable and efficient electrical control. Johnson Controls, a leader in building technologies, produces cutting-edge relays used in HVAC systems and building automation to optimize energy consumption and improve comfort. MARS specializes in producing durable and reliable electrical components, including relays, for a variety of applications., a trusted supplier of electrical products, stocks a wide selection of relays from these reputable brands, providing customers with easy access to top-quality electrical components for their diverse needs.

System Sensor D4120 System Sensor 4-wire low flow smoke detector photo

Brand: System Sensor
SKU: D4120
Order QuantityUnit Price
1 - 5$138.05
6 - 11$133.91Save 3%
12+$129.77Save 6%
In Stock! Ships in 24 hours
Availability: 242

Model D4120 and D4S Duct Smoke Detectors utilize 4-wire photoelectric technology for the detection of smoke. This detection method, when combined with an efficient housing, samples air passing through the duct allowing detection of a developing hazardous condition. When sufficient smoke is sensed, an alarm signal is initiated and appropriate action can be taken to shut off fans, blowers, change over air handling systems, etc. These actions can facilitate the management of toxic smoke and fire gases throughout the areas served by the duct system.System Sensor 4-wire low flow smoke detector photo electric type

Product Family

Model NumberDecriptionManufacturerPriceAvail. Qty 
D4120 System Sensor 4-wire low flow smoke detector photo System Sensor $138.05 242    Add To Cart

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