SN-PR46A is a PIR motion sensor, a new energy-saving switch. It adopts three good sensitivity detectors in an integrated circuit. This sensor gathers automatism, convenience, safety, energy-saving, and practical functions. It utilizes the infrared energy from the human body as a control signal source and it can start the load at once when one enters the detection field. It can automatically identify day and night and is easy to install and a widely used product.