Abstract: A circuit for detecting electromagnetic radiation includes a pyroelectric sensor element connected to convert electromagnetic radiation into an electric signal. An n-channel junction field effect transistor is connected to receive the electric signal. A printed circuit board includes at least one low inductance low resistance area to provide a ground path for all alternating current components. A first capacitor is connected between the FET source terminal and a second capacitor is connected between the FET drain terminal and ground. A gate resistor is connected in parallel with the sensor element or a resistor is included in the sensor elements.

Abstract: A radiation sensor (10) comprises one or more radiation sensing elements (1) providing an electric signal in dependence of incident radiation, a housing (4, 5) confining the sensing element and permitting incidence of radiation from outside onto the sensing element, plural terminals (7) for supplying electrical power to the sensor and at least for outputting a sensor output signal, and circuitry (2) receiving the electric signal of the sensing element and providing the output signal in accordance with the electric signal of the sensing element. The circuitry comprises a switching signal circuitry for generating an on/off output signal for a switchable component external to the sensor and/or a digital output signal circuitry for providing a multiple bit serial output signal, and the sensor has one output terminal (7a) for outputting the on/off output signal or the multiple bit serial output signal.

Abstract: A pyroelectric material is made of lithium tantalate treated to an extent that a bulk resistivity is in a range of less than 2e+14?*cm, preferably less than 5e+12?*cm, but more than a lower threshold is obtained.

Abstract: A circuit for detecting electromagnetic radiation such as infrared radiation includes one or more sensor elements which convert the electromagnetic radiation into an electric signal. A field effect transistor receives the electric signal of the sensor elements. An impedance which is ohmic, inductive, or both is connected between the supply voltage and the field effect transistor to filter high frequencies so that false detections by the detecting circuit are eliminated.

Abstract: An infrared detector has two infrared detector elements contained in a housing, the housing having a window which is transmissive for infrared radiation, and further electrical components interconnected with the detector elements are also contained in the housing. The housing is formed of a shaped plastic part in which a shaped sheet metal element and the electrical components are embedded. The shaped sheet metal component electrically connects the electrical components, and is provided with outward projections serving as the exterior terminal pins. The shaped sheet metal component has angled regions which are bent to surround at least a portion of the electrical components for shielding thereof.

Abstract: The invention is directed to an infrared motion alarm characterized by an infrared detector and an optical arrangement before the detector in the radiation direction for focussing the infrared radiation onto the detector. The optical arrangement is formed by a mirror arrangement and by a lens arrangement with the mirrors being on different levels so the different beam paths are being detected to prevent an intruder from crawling under the infrared detection beam paths.