Apparatus for high voltage resistance measurement

• US 3,984,768 A
• Filed: 06/11/1975
• Issued: 10/05/1976
• Est. Priority Date: 06/11/1975
• Status: Expired due to Term

• Current Assignee: Champion Spark Plug Company
• Original Assignee: Champion Spark Plug Company
• Inventors: Staples, James T.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/585,785
• Time in Patent Office: 482 Days
• Field of Search: 324/62, 324/15
• US Class Current: 324/712
• CPC Class Codes: G01R 27/02 Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant by measuring phase angle only G01R25/00

Abstract

Improved method and apparatus for measuring the effective operating resistance of an unknown resistance element to which repetitive high voltage pulses are normally applied during operation. As each high voltage pulse is applied to the element, the voltage across the element and the current through the element are simultaneously sampled during voltage peak or at any other desired point in each pulse. The voltage and current samples are digitized and used in digitally computing the effective operating resistance of the unknown element. The computed resistance is displayed on a digital indicator.

Claims

1. Apparatus for measuring the effective electrical resistance of an unknown element while subjected to repetitive high voltage pulses comprising, in combination, means for applying repetitive short duration high voltage pulses to the unknown element, means for generating a first analog voltage proportional to the voltage across the unknown element, means for generating a second analog voltage proportional to the current through the unknown element, first means responsive to a trigger signal for temporarily storing such first analog voltage, second means responsive to a trigger signal for temporarily storing such second analog voltage, means responsive to said high voltage applying means for simultaneously applying trigger signals to said first and second storing means at a predetermined point in each high voltage pulse applied to the unknown element, first means for digitizing the first analog voltage stored in said first storing means, second means for digitizing the second analog voltage stored in said second storing means, means for triggering both of said first and second digitizing means a predetermined time after new analog voltages are stored in said first and second storage means, means responsive to the digitized outputs from said first and second digitizing means for generating digital resistance data corresponding to the resistance of the unknown element, and display means responsive to such generated digital resistance data for indicating the resistance of the unknown element.

2. Apparatus for measuring the effective electrical resistance of an unknown element, as set forth in claim 1, and further including means for expanding by a predetermined factor at least one of the digitized outputs from said first and second digitizing means, and wherein said digital resistance data generating means is responsive to such expanded output for generating digital resistance data.

3. Apparatus for measuring the effective electrical resistance of an unknown element, as set forth in claim 1, wherein said means for generating digital resistance data comprises dividing means including means for generating the 2'"'"'s complement of the digitized output from said second digitizing means, summing means for adding such 2'"'"'s complement to the digitized output from said first digitizing means to obtain a sum and for repeatedly adding such 2'"'"'s complement to the prior sum, means responsive to such sum equaling zero for inhibiting said summing means, means responsive to a change in the sign of such sum for inhibiting said summing means, and means for counting the number of times such 2'"'"'s complement is added by said summing means, such count comprising the digital resistance data.

4. Apparatus for measuring the effective electrical resistance of an unknown element, as set forth in claim 3, and further including means for expanding the digitized output from said first digitizing means by a predetermined factor, and wherein said summing means adds such 2'"'"'s complement to such expanded digitized output from said first digitizing means.