Schaltungsanordnung für einen optischen Melder zur Umweltüberwachung und Anzeige eines Störmediums

摘要

Circuit arrangement for an optical detector, using the transmitted-light principle, for environmental monitoring and indication of a disturbing medium (gas or smoke), in particular for triggering an alarm, having a light source which irradiates both a measuring photoelectric cell (photoelectric tube, photoemissive detector) (11) via a measured-beam path which is subject to the disturbing medium, and a reference photoelectric cell (12) via a reference beam path which is kept free from the disturbing medium, a comparison signal being derived from comparing the received signals emitted by the measuring photoelectric cell and the reference photoelectric cell. The light source consists of a plurality of semiconductor light emitters which have in each case a different light spectrum and emit flashes of light by being modulated at a clock frequency.