Battery testing device

Claim 1

A CAMERA BATTERY TESTING DEVICE COMPRISING: (A) AN ELECTRIC MEASURING INSTRUMENT HAVING A COIL MEANS MOVEABLE WITHIN A MAGNETIC FIELD THROUGHOUT A FIRST OPERATING RANGE, SAID COIL MEANS BEING ADAPTED TO REST IN EQUILIBRIUM IN ANY POSITION WITHIN SAID FIRST RANGE IN RESPONSE TO LACK OF ELECTRIC CURRENT IN SAID COIL AND BEING ADAPTED TO DEFLECT IN OPPOSITE DIRECTIONS THROUGHOUT SAID FRIST RANGE SOLELY IN RESPONSE TO ELECTRIC CURRENTS IN CORRESPONDING RELATIVELY OPPOSITE DIRECTION IN SAID COIL; (B) SWITCH MEANS FOR ELECTRICALLY CONNECTING SAID BATTERY IN SERIES WITH SAID COIL FOR DEFLECTING THE LATTER INTO A SECOND RANGE BEYOND ONE END OF SAID FIRST RANGE; (C) A SPRING MEANS INEFFECTIVE TO OPPOSE MOVEMENT OF SAID COIL WHENEVER SAID COIL IS IN SAID FIRST RANGE AND RENDERED OPERABLE ONLY UPON DEFLECTION OF SAID COIL INTO SAID SECOND RANGE DIFFERENTIALLY RESISTING SUCH SECOND RANGE DEFLECTION OF SAID COIL, FOR POSITIONING SAID COIL WITHIN SAID SECOND RANGE AS A FUNCTION OF THE POTENTIAL OF SAID SOURCE; (D) A POINTER MOVABLE WITH SAID COIL; AND (E) A SCALE BEARING BATTERY POTENTIAL INDICIA AND COOPERABLE WITH SAID POINTER DURING SAID SECOND RANGE DEFLECTION FOR INDICATING BATTERY POTENTIAL.