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US 4,230,988 AGranted
Resistance neutralizing system for electrochemical devices
AssigneeHewlett-Packard Company
InventorRaymond B. Stelting
Life of this patent
Estimating the term…
Abstract
The net resistance of a circuit for utilizing an electrochemical cell is reduced by inserting negative resistance in the circuit that is slightly less than the inherent resistance of the cell, and means are provided for automatically adjusting the amount of negative resistance in response to the inherent resistance of the cell employed.
Claims14
Apparatus for measuring the concentration of a gas, comprising
- an electrochemical cell having first and second electrodes and arranged to contain an electrolyte between said electrodes, said cell having resistance associated with each of its electrodes and its electrolyte when the electrolyte is present in the cell and capacitance between each electrode and the electrolyte when the electrolyte is present in the cell,
- a source of direct current potential,
- means providing negative resistance,
- means connecting said cell, said source of direct current potential and said means for producing negative resistance in a circuit, and
- means for measuring direct current flowing in said circuit.
2 more elements
A system for neutralizing the effect of resistance associated with an electrochemical cell comprising
- an electrochemical cell having first and second electrodes and an electrolyte between them, said electrodes and said electrolyte each having a given resistance, there being capacitance between each electrode and said electrolyte,
- a source of direct current voltage connected between one of said electrodes and ground,
- an operational amplifier having an inverting input, a non-inverting input and an output,
- a connection between the inverting input and the other of said electrodes,
- a resistor connected between said inverting input of said amplifier and its output,
- means providing a variable first resistance connected between the non-inverting input of said amplifier and ground so as to form a circuit,
- means providing a second resistance connected between the non-inverting input of said amplifier and its output,
- means for measuring any direct current flowing in said circuit,
- means for causing an alternating tracer current to flow in said circuit, and
- control means for varying the value of said first resistance as a function of the voltage drop produced by said tracer current across the given resistances of said cell.
7 more elements
Apparatus for measuring the concentration of a gas, the apparatus comprising
- an electrochemical cell having first and second electrodes and arranged to contain an electrolyte between the electrodes, the cell having resistance associated with each of its electrodes and capacitance between each electrode and the electrolyte when the electrolyte is present in the cell,
- means providing negative resistance,
- terminals between which a source of potential may be connected,
- means for connecting the electrodes of the cell, the negative resistance and said terminals in a series circuit, and
- means for measuring any direct current flowing in said circuit.
2 more elements
Dependencies are inferred from the claim text.