Abstract A meter for measuring electrical characteristics of a load including resistance R and capacitance C with metallic electrodes contactable by an aqueous liquid, including a test specimen electrode, a reference electrode and a third or auxiliary electrode. A current loop circuit connects the test specimen and third electrodes to a first input and common output of a differential amplifier and a direct current supply means. Polarizing current in the current loop circuit passes through the third electrode and the test specimen electrode to produce an exponential voltage change at the test specimen electrode with a time constant of resistance and capacitance about this electrode. A voltage loop circuit connects the test specimen electrode and the reference electrode between the first and second inputs of the differential amplifier. A signal generating source in the voltage loop circuit produces a voltage signal changing exponentially from a first value to a second value with the resistance-capacitance time constant characteristic of the polarizing voltage change at the test specimen electrode. The voltage signal and polarizing voltage change combine as an input signal across the first and second inputs of the differential amplifier to produce the polarizing current flow in the current loop circuit at a substantially constant value until a predetermined polarizing voltage is generated at the test specimen electrode. Means provide a read-out of the constant value of current flow through the test specimen electrode and the third electrode while the voltage signal is changing exponentially. The value of current flow can be correlated to the electrical characteristics at the test specimen electrode.
A meter for measuring electrical characteristics of a load including resistance R and capacitance C which comprises: a. a circuit including an electrical load having an RC time constant characteristic; b. a potential generating source including a current supply means for providing an output current in response to an electrical input signal, said potential generating source connected to said circuit whereby current flow produces an exponential voltage change in the load with a time constant of RC; c. control means including a signal generating source for providing an electrical signal to said potential generating source, said signal changing exponentially from a first value to a second value with a time constant RC until a predetermined voltage is generated in said load by current flow of substantially constant value from said potential generating source to said load; and d. means for providing a read-out of said constant value of current flow indicative of the electrical characteristics of said load while the electrical signal changes exponentially.
Claim 2
Dependent Claim
164 words
A meter for measuring electrical characteristics of a load including resistance R and capacitance C which comprises: a. a circuit including an electrical load having an RC time constant characteristic; b. a potential generating source including a current supply means for providing an output current in response to an electrical input signal, said potential generating source connected to said circuit whereby current flow produces an exponential voltage change in the load with a time constant of RC; c. control means including a signal generating source for providing an electrical signal to said potential generating source, said signal changing exponentially from a first value to a second value with a time constant RC until a predetermined voltage is generated in said load by current flow of substantially constant value from said potential generating source to said load; and d. means for providing a read-out of said constant value of current flow indicative of the electrical characteristics of said load while the electrical signal changes exponentially.
Claim 3
Dependent Claim
37 words
The meter of claim 1 wherein the electric signal is varied between certain first and second values by said control means whereby the voltage generated in the load changes from an initial value to said predetermined voltage.