Abstract: A headlamp for motor vehicles has a reflector, a discharge lamp located in front of the reflector, a glass envelope surrounding the discharge lamp and being transparent in certain sections to light of specific wavelengths, a lamp carrier which holds the discharge lamp so that the discharge lamp is arranged in a space limited at least by the lamp carrier and the glass envelope. The glass envelope blocks UV light in UV-A, UV-B and UV-C wavelength range.

Abstract: A headlight for motor vehicles has a reflector, a gas discharge lamp inserted in the reflector, an electrical pre-switching device arranged to supply the gas discharge lamp with high voltage, a lamp support via which the gas discharge lamp is inserted in the reflector, a detachable protective cap which covers the lamp support and the gas discharge lamp at their rear, an electrical line connected with the pre-switching device, and a switch arranged in the line and openable when the protective cap is removed so that the operation of the gas discharge lamp is prevented when the switch is opened.

Abstract: An interrogator-responsor system which permits the transmission of a number of different interrogation codes. Means are provided for changing the interrogator and responsor codes according to a time program and means are also provided to synchronize the program in each of the interrogator and responsor units. The interrogator has means for comparing the interrogator code with the code of the answering signal from the responsor to permit evaluation of the answering signal when the interrogator code and the answering code are in agreement.