James P Dougherty

US Patent:

61983020, Mar 6, 2001

Filed:

Apr 2, 1998

Appl. No.:

9/054182

Inventors:

James R. Dougherty - Mesquite TX

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

G01R 3136

US Classification:

324771

Abstract:

A control circuit, system for, and method of, testing a device under test (DUT) coupled to a load having a controllable load current level. The DUT is capable of operating in a regulated range and an unregulated range. In one embodiment, the control circuit includes: (1) minimum and maximum current control stages that set minimum and maximum load current values, respectively, for the control circuit and (2) an integrator, coupled to the DUT. In a constant current mode, the integrator selects one of the minimum and maximum load current values to control the load current level and test the DUT while the DUT is operating in the regulated range. In a constant voltage mode, the integrator produces an intermediate load current value based on a relationship between a voltage of an output of the DUT and a reference voltage to control the load current level and test the DUT while the DUT is operating in the unregulated range.

US Patent:

41183002, Oct 3, 1978

Filed:

Jun 28, 1977

Appl. No.:

5/810834

Inventors:

Joe M. Victor - Houston TX
James Dougherty - Houston TX

Assignee:

Petrolite Corporation - St. Louis MO

International Classification:

G01N 2744

US Classification:

204195T

Abstract:

A coulometric titrator for determining, at high accuracy and without time delay problems, small amounts of a specific ion in a solution by the addition of a reactive ion. A sensor provides a signal voltage representing the logarithm of the specific ion concentration to a differential amplifier which also receives as an input a signal from a reference electrode. The differential amplifier produces an error signal applied to a comparator and referenced therein to a certain reference voltage representing a desirable range of rates of change of the error output voltage. The comparator provides a sensor signal voltage representing the difference between the error signal and reference voltage. This sensor signal voltage is applied to an antilogarithm converter which produces an output signal that is proportional to the antilogarithm of the sensor signal voltage. The output signal is received by a reactive ion (silver metal) source means associated with a current source passing a unidirectional current flow between an inert cathode immersed in the solution and the reactive ion source means as an anode for the introduction of the reactive ion (silver) into the solution.