System for indicating interruption in operation of automotive lamps

A system for indicating interruption in operation of automotive lamps comprising;

• a voltage source;
• a plurality of automotive lamps;
• a switch and a current winding connected between said source and said automotive lamps, said switch being operable to connect said source to the lamps for energization thereof and for passing current through said winding thereby generating magnetomotive force in proportion to the amount of current flowing therethrough;
• a voltage winding connected to said source via said switch for generating a magnetomotive force opposite to that generated by said current winding;
• a zener diode connected in series with said voltage winding for allowing current to flow from the source through said voltage winding only when voltage applied across said diode exceeds a predetermined value;
• additional switch means actuated in response to the net magnetomotive force generated by said windings;
• and
• indicating means connected to said additional switch means and responsive to the actuation of said additional switch means when at least one of said lamps is inoperative.