Contact breaker protection of low voltage halogen lamps - having monitored current compared with threshold valve to control supply to lamp

摘要

The output of a mains transformer (2a) is coupled to one or more low voltage halogen lamps (1) and one connection is made to a mechanical relay (3a) that provides automatic circuit breaking if a dangerous condition arises. The circuit has a current monitoring stage (4) coupled to an averaging stage (5) providing an input to a timer (6) connected to the start button (7). A comparator receives the value stored in a memory (8) and compares it with the measured current value. A threshold detection stage (10) can generate a signal that results in cut out if a safe value is exceeded. ADVANTAGE - Contact breaker circuit protects halogen lamp against overload.