Abstract A protective device operative upon the failure of a transistor, which is designed such that when a short-circuit occurs between the collector and emitter of a transistor for controlling the supply of current to a load or when the lead connecting said load to the collector of said transistor is grounded directly connecting the load to the ground, the fault may be readily detected so that a fuse provided between the load and a power source is caused to blow and a warning means such as a lamp is caused to give warning to the operator about the occurrence of the fault and at the same time the supply of current to the load is forcibly interrupted, thereby eliminating various defects that would be otherwise caused by any unnecessary supply of current to the load.
A protective device operative upon the failure of a transistor: comprisiNg an actuating transistor (2) having the collector thereof connected to a loads (1); a drive transistor (8) for conducting said actuating transistor (2) upon receipt of an input signal; a reversing transistor (5) adapted to be biased in the forward direction so as to be rendered conductive only when said drive transistor (8) is in the non-conduction state with no input signal being applied thereto and at the same time there is a short-circuit between the collector and emitter of said actuating transistor (2) or said load (1) is directly connected to the ground; and a fuse (7) connected to a power source, said load (1) and the collector of said reversing transistor (5).
Claim 2
Dependent Claim
125 words
A protective device operative upon the failure of a transistor: comprisiNg an actuating transistor (2) having the collector thereof connected to a loads (1); a drive transistor (8) for conducting said actuating transistor (2) upon receipt of an input signal; a reversing transistor (5) adapted to be biased in the forward direction so as to be rendered conductive only when said drive transistor (8) is in the non-conduction state with no input signal being applied thereto and at the same time there is a short-circuit between the collector and emitter of said actuating transistor (2) or said load (1) is directly connected to the ground; and a fuse (7) connected to a power source, said load (1) and the collector of said reversing transistor (5).
Claim 3
Dependent Claim
38 words
A protective device operative upon the failure of a transistor according to claim 1, wherein there is further provided a transistor (10) for detecting the collector potential of said reversing transistor (5) to actuate a warning means (12).