Digital dimming and flashing circuit for locomotive ditch lights

摘要

A light is dimmed by pulsing it at a selected duty cycle. By pulsing, the light can be dimmed without being turned off completely which reduces wear on the filament. The circuit is designed for flashing a pair of ditch lights on a railroad locomotive. The lights are alternately illuminated at full voltage and dimmed by pulsing. The flashing sequence can be activated when the locomotive is travelling below a selected speed or when the horn is sounded. The duration of the flashing sequence is controlled by a timer. The pulsing circuit can be used to effectively reduce a voltage without voltage dropping resistors.