Safety device for lamps of motor vehicle

Claim 1

A safety device for indicating the operating conditions of signal lights and switches, comprising: a plurality of circuit elements forming a first circuit path through one of the signal lights and one of the switches, said plurality of circuit elements including a primary winding of a current transformer coupled to one side of said one signal light and a rectifying diode in series with said one light, said primary winding, said one switch and a current source; a second plurality of circuit elements forming a second circuit path through said one light, said second plurality of circuit elements including a checking light connected to said one side of said one signal light, a resistor, and a second current source in series with said one signal light and said checking light, said checking light having a higher resistance than said one signal light, whereby when said one switch is open, current flows through said second circuit path and causes said checking light to glow visibly if said one signal light is in operating condition; a secondary winding magnetically coupled to said primary winding; an amplifier circuit coupled to said secondary winding for amplifying current in said secondary winding; and an indicator light coupled to the output of said amplifier, such that current flowing through said first circuit path induces a current in said secondary winding and causes said indicator light to glow visibly; whereby if both said one signal light and said one switch are operational, said checking light will glow when said switch is open and said indicating light and said one signal light will glow when said one switch is closed, and if said one signal light is not operational, none of the said lights will glow, and if said one signal light is operational and said one switch is not operational, said checking light will glow continuously.