Variable monitoring system

Claim 1

MONITORING APPARATUS FOR MONITORING THE CONDITIONS OF A NUMBER OF VARIABLES COMPRISING: INDIVIDUAL DETECTING CIRCUITS FOR THE VARIABLES EACH COMPRISING: CONDITIONRESPONSIVE IMPEDANCE MEANS AND OTHER IMPEDANCE MEANS ACROSS WHICH THE VOLTAGE DROP VARIES WITH THE CONDITION OF THE ASSOCIATED VARIABLE, A SOURCE OF ENERGIZING POTENTIAL CONNECTED TO SAID CONDITION-RESPONSIVE IMPEDANCE MEANS AND OTHER IMPEDANCE MEANS, AND FIRST CONTROL MEANS RESPONSIVE TO A GIVEN CONDITION OF THE ASSOCIATED VARIABLE AS DETERMINED FROM THE IMPEDANCE OF SAID VARIABLE RESPONSIVE IMPEDANCE MEANS; AND A COMMON CIRCUIT FOR MEASURING THE VALUES OF ALL OF SAID VARIABLES, SAID COMMON CIRCUIT INCLUDING A COMMON VARIABLE IMPEDANCE MEANS FORMING ONE ARM OF A BRIDGE CIRCUIT, OTHER COMMON IMPEDANCE MEANS FORMING ANOTHER ARM OF A BRIDGE CIRCUIT AND CONNECTED IN SERIES WITH SAID VARIABLE IMPEDANCE MEANS AND A PAIR OF BRIDGE ENERGIZING INPUT TERMINALS COUPLED TO THE UNCONNECTED ENDS OF THE LAST TWO MENTIONED IMPEDANCE MEANS, SCANNING SWITCH MEANS FOR SEQUENTIALLY CONNECTING SAID BRIDGE ENERGIZING INPUT TERMINAL MEANS TO THE UNCONNECTED OUTER ENDS OF SAID IMPEDANCE MEANS OF EACH OF SAID DETECTING CIRCUIT FOR FORMING THEREWITH AN OPERATIVE BEIDGE MEASURING CIRCUIT WHERE THE LAST MENTIONED IMPEDANCE MEANS FORMS TWO ARMS THEREOF AND WHICH IS ENERGIZED BY THE VOLTAGE DEVELOPED ACROSS THE SCANNED CONDITION-RESPONSIVE IMPEDANCE MEANS AND THE ASSOCIATED OTHER IMPEDANCE MEANS OF THE SCANNED DETECTING CIRCUITS, BRIDGE BALANCING MEANS FOR VARYING SAID COMMON VARIABLE IMPEDANCE MEANS UNTIL THE OPERATIVE BRIDGE CIRCUIT IS BALANCED, AND SECOND CONTROL MEANS INCLUDING VARIABLE VALUE INDICATING MEANS RESPONSIVE TO SAID BRIDGE BALANCING MEANS FOR INDICATING THE VALUE OF THE VARIABLE SCANNED.