PASSIVE INFRARED DETECTOR

摘要

A passive infrared detector including an optical collector releasably attached to a base with a sensor on which incident infrared radiation directed through the optical collector is focused. The sensor is held by a joint member which is pivotally supported on the base and to which said optical collector is releasably attached, whereby the optical collector is rotatable together with the joint member relative to the base for adjustment its angular position and the optical collector can be alone replaced as necessary without having to replace the base, the sensor and its associated electric circuitry.