Results of an Investigative Study of the Current Decay Test for the Evaluation of Incandescent Lamps

The nondestructive testing (NDT) of automotive incandescent lamps to evaluate lamp quality during the manufacturing process is continually under development. Recently a method has been proposed to test lamps by measuring the current decay the lamp experiences during a two second light up. In the work by Lynn, tests were done on acceptable lamps and lamps with large leaks such as which would occur if a tip were broken off(1. ). In this paper, this method is studied further with similar lamps and compared with two other NDT methods which are currently in use and accepted by the automotive lamp making industry, namely “Spark Coiling”and “Digital Vision” inspection. This paper shows the results of the test methods when used on lamps with large and small air leaks and acceptable lamps.