Fuse checker for testing integrity of a miniature, plug-in fuse while the fuse is installed in an electrical circuit

A fuse checker for testing the integrity of a miniature, plug-in fuse while the fuse is in operative position in a direct current electrical circuit, said checker comprising:

• (a) a fuse checker housing including a pair of outwardly extending fuse terminal contacts that are each receivable in a respective one of a pair of spaced recesses formed in a fuse housing of a miniature, plug-in fuse for making electrical contact with respective end portions of a fuse-forming link extending between and connected with a pair of fuse terminals extending from the fuse housing, wherein the fuse terminal contacts are spaced from each other a distance corresponding with the spacing between the recesses in the fuse housing and wherein the fuse terminal contacts each are of a size to permit each terminal contact to be received in a respective one of the recesses in the fuse housing and to be electrically connected with the respective end portions of the fuse-forming link;
• (b) a pair of light sources carried by the fuse checker housing, and a current limiting resistor connected in series with each of the light sources, wherein each light source is a light emitting diode that includes a pair of terminals, a first terminal of each light emitting diode electrically connected with a respective one of said fuse terminal contacts;
• and
• (c) a ground contact extending form the fuse checker housing and electrically connected with a second terminal of each of the light emitting diode light sources through its associated resistor for completing a unidirectional electrical flow path through the respective light sources from the respective fuse terminal contacts to a ground connection of a circuit including the fuse-forming link to be integrity tested for indicating the operative condition of a fuse, wherein upon energizing the circuit that includes the fuse-forming link to be integrity tested both light emitting diode light sources emit light when the fuse-forming link is intact, and wherein only one of the light emitting diode light sources emits light when the fuse-forming link has been severed, to visually indicate the operative condition of the fuse while the fuse is in an operative position in the circuit.