Vehicle detector with battery storage element

Claim 1

A VEHICLE DETECTOR COMPRISING: AN ELECTRONIC AMPLIFYING DEVICE HAVING FIRST AND SECOND CONTROL TERMINALS AND AN OUTPUT TERMINAL; FOR SUPPLYING AN OUTPUT SIGNAL IN RESPONSE TO THE RELATIVE POTENTIAL BETWEEN SAID FIRST AND SECOND CONTROL TERMINALS; A DETEECTOR LOOP; CIRCUITRY CONNECTED TO SAID LOOP AND SAID FIRST INPUT TERMINAL FOR VARYING THE POTENTIAL OF SAID FIRST TERMINAL IN RESPONSE TO A CHANGE IN THE IMPEDANCE OF SAID LOOP; A CIRCUIT CONNECTED TO RECEIVE SAID OUTPUT SIGNAL AND CONNECTABLE TO OPERATE A RECORDING DEVICE IN ACCORD WITH A CHANGE IN ONE SENSE, OF SAID OUTPUT SIGNAL; A FEEDBACK TERMINAL CONNECTED TO SAID LAST MENTIONED CIRCUIT, SAID CIRCUIT FOR PRODUCING AT THE FEEDBACK TERMINAL, A FEEDBACK SIGNAL OF A VALUE WHICH, IF APPLIED TO A SECOND CONTROL TERMINAL OF SAID ELECTRONIC AMPLIFYING DEVICE, WOULD COMPENSATE FOR THE CHANGE AT THE FIRST INPUT TERMINAL SUFFICIENTLY TO PREVENT SUBSTANTIVE VARIATION OF SAID OUTPUT SIGNAL; A CONNECTION FROM SAID FEEDBACK TERMINAL THROUGH A RECTIFIER TO SAID SECOND FEEDBACK TERMINAL; THE ORIENTATION OF THE SAID RECTIFIER BEING SUCH THAT IT PRESENTS A SUBSTANTIALLY OPEN CIRCUIT TO POTENTIALS AT THE FEEDBACK TERMINAL IN THE SENSE OF THE CHANGE OF THE FIRST CONTROL TERMINAL RELATIVE TO THE SECOND CONTROL TERMINAL, WHICH IT IS DESIRED TO RECORD; AT LEAST ONE VARIABLE VOLTAGE RECHARGEABLE BATTERY CONNECTING SAID SECOND CONTROL TERMINAL TO A DIRECT CURRENT DATUM, A LEAKAGE RESISTANCE CONNECTING SAID SECOND CONTROL TERMINAL TO A DIRECT CURRENT DATUM OF A POTENTIAL IN THE SAME SENSE RELATIVE TO THE POTENTIAL OF SAID SECOND CONTROL TERMINAL AS THE SENSE OF THE CHANGE OF THE FIRST CONTROL TERMINAL WHICH IT IS DESIRED TO RECORD.