摘要 |
<p>A discharge lamp with high intensity and high local stability is disclosed, which is suitable for use as a light source in a visibility meter. A light receiver also suitable for use in a visibility meter is disclosed. The discharge lamp has a discrete anode chamber and a discrete cathode chamber which are both filled with gas and which are interconnected via a capillary tube. One end of the capillary tube is adjacent a cathode located within the cathode chamber, while the other end of the capillary tube projects forwardly of a region in which the anode is adjacent the capillary tube. Plasma is confined within the capillary tube, resulting in a high local stability and high intensity light output. The light receiver utilizes a photosensitive element and an electrical filter which is so designed that response of the light receiver is calibrated to include or coincide with that portion of the visible light spectrum which carries maximum energy.</p> |