Flasher circuit with outage indication

Claim 2

A flasher circuit of the type adapted to intermittently energize a signal lamp load from a voltage source including an oscillator for producing intermittent control signal impulses, a switching device adapted to be switched between on and off conditions in response to said control signal impulses to connect and disconnect the load and the voltage source, the improvement comprising control means connected in circuit with said load and effective to change from a first condition to a second condition when the magnitude of the current through the load decreases below a predetermined value, said control means being effective in said second condition to hold said switching device in said on condition whereby a decrease of said current below said predetermined value causes the remaining signal lamps to be continuously energized from said voltage source to indicate the outage of onE of said signal lamps.

Claim 3

The invention as defined in claim 1 wherein said control means is a current-responsive device having an input circuit connected with said load circuit and an output circuit operatively connected with said switching device.

Claim 4

The invention as defined in claim 2 wherein said control means comprises a relay having an energizing winding in said load circuit and having switch contacts operatively connected with said switching device.

Claim 5

The invention as defined in claim 3 wherein said oscillator is a multivibrator comprising a pair of cross-coupled transistors and the switch contacts of said relay are connected in the input circuit of one of said transistors.

Claim 6

A flasher circuit for automotive vehicles and adapted to intermittently energize a load circuit including signal lamps from a voltage source, an oscillator for producing intermittent control signal impulses, a switching device connected with the oscillator and adapted to be switched between on and off conditions in response to the intermittent control signal impulses to connect and disconnect the load circuit and the voltage source, first control means having an input connected across the load and having an output connected to the switching device, said first control means being adapted to change from a first conductive state to a second conductive state when the voltage across the input thereof decreases below a predetermined value and being effective in said second conductive state to hold said switching device in said off condition to deenergize the load in the event of a short circuit, second control means having an input connected with the load circuit and an output operatively connected with said switching device, said second control means being adapted to change from a first conductive state to a second conductive state when an open circuit occurs in one of the signal lamps and the current through said load decreases below a predetermined value, said second control means being effective in the second conductive state to hold said switching device in the on condition and continuously energize the remaining signal lamps in the load circuit.

Claim 7

A flasher circuit for automotive vehicles and adapted to intermittently energize a load circuit including signal lamps from a voltage source, an oscillator for producing intermittent control signal impulses, a switching device connected with the oscillator and adapted to be switched between on and off conditions in response to the intermittent control signal impulses to connect and disconnect the load circuit and the voltage source, first control means having an input connected across the load and having an output connected to the switching device, said first control means being adapted to change from a first conductive state to a second conductive state when the voltage across the input thereof decreases below a predetermined value and being effective in said second conductive state to hold said switching device in said off condition to deenergize the load in the event of a short circuit, second control means having an input connected with the load circuit and an output operatively connected with said switching device, said second control means being adapted to change from a first conductive state to a second conductive state when an open circuit occurs in one of the signal lamps and the current through said load decreases below a predetermined value, said second control means being effective in the second conductive state to hold said switching device in the on condition and continuously energize the remaining signal lamps in the load circuit.

Claim 8

The invention as defined in claim 5 wherein said first control means is a voltage-responsive device and said second control means is a current responsive device.

Claim 9

The invention as defined in claim 6 wherein said current responsive device is a relay having an energizing winding in circuit with the load and having switch contacts operatively connected with the switching device.

Claim 10

The invention as defined in claim 7 wherein said oscillator is a multivibrator comprising a pair of cross-coupled transistors and the switch contacts of said relay are connected to the input of one of said transistors to hold the multivibrator in one stable state when the contacts are closed.