Enhancing voltmeter functionality

• US 6,356,853 B1
• Filed: 12/27/1999
• Issued: 03/12/2002
• Est. Priority Date: 07/23/1999
• Status: Expired due to Term

• Current Assignee: Daniel B. Sullivan
• Original Assignee: Daniel B. Sullivan
• Inventors: Sullivan, Daniel B.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Barbee, Manuel L.
• Application Number:
  US09/472,425
• Time in Patent Office: 806 Days
• Field of Search: 702/64, 702/65, 702/108, 702/117-121, 702/126, 702/182-185, 324/537, 324/126, 324/115, 324/99.D, 324/72.5, 324/522
• US Class Current: 702/117
• CPC Class Codes: G01R 1/36 Overload-protection arrangements or circuits for electric measuring instruments
• CPC Class Codes: G01R 15/125 for digital multimeters
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58

Abstract

Enhanced voltmeter leads includes load circuitry having a test load that can be switchably coupled between the leads to help identify faults in a circuit under test. In certain embodiments, the value of the test load can be any appropriate value set according to parameters or characteristics of the circuit under test. In these embodiments, the value of the test load can be set manually or automatically or both. The types of faults that can be identified include a short-to-ground, an open circuit, and a high (e.g., corrosive) resistance. The leads include a switch whose setting is adjustable to couple and decouple the test load between the leads. The switch can be located in the leads or in a lead handle of the leads for easy access by a user/technician. The leads can also include a fuse or circuit breaker for safety reasons. The leads can be used systematically to help identify the type and location of a fault from voltage readings. The voltage readings are obtained at various points in the circuit under test with the switch both closed and open. Conventional test leads or the leads that include the switch to couple/decouple the test load can be used if the load circuitry is integrated into the voltmeter or if the load circuitry has a separate coupling or connection to the voltmeter inputs.

Claims

1. Circuitry for dynamic testing of a circuit under load, comprising:

a test load adapted to be coupled between inputs of a digital voltmeter, the test load replacing a component of the circuit under load; and

a switch adapted to short circuit test leads of the voltmeter through the test load.

2. The circuitry of claim 1, wherein the switch is adapted to be closed to complete the circuit under load.

3. The circuitry of claim 1, wherein the switch, when closed, is adapted to allow dynamic testing of the circuit under load.

4. The circuitry of claim 1, wherein the test load and the switch are incorporated in the voltmeter.

5. The circuitry of claim 1, wherein the test leads comprise conventional test leads.

6. The circuitry of claim 1, wherein the test load comprises a resistive load.

7. The circuitry of claim 1, wherein the test load comprises a load adapted to drop an equivalent voltage drop to a removed component of the circuit under load.

8. A method for dynamic testing of a circuit under load, the method comprising:

removing a component from the circuit under load;

coupling leads of a digital voltmeter to remaining terminals of the removed component in the circuit;

closing a switch to short circuit inputs of the digital voltmeter through a test load; and

making dynamic tests of the circuit under load using the digital voltmeter, the test load completing the circuit under load.

9. The method of claim 8, further comprising using a test load of comparable resistive load value as the removed component.

10. The method of claim 8, wherein the completing the circuit under load comprises ensuring that a maximum current in the circuit under load remains below a maximum allowable for circuit under load.

11. An enhanced functionality digital voltmeter comprising:

circuitry for dynamic testing of a circuit under load, comprising;

a test load adapted to be coupled between inputs of a digital voltmeter, the test load replacing a component of the circuit under load; and

a switch adapted to short circuit test leads of the digital voltmeter through the test load.

12. The enhanced voltmeter of claim 11, further comprising test leads adapted to be coupled to the circuit under load and to couple the test load to the circuit under load.

13. A method of enhancing digital voltmeter functionality, the method comprising:

incorporating, in a digital voltmeter, circuitry for dynamic testing of a circuit under load, comprising;

incorporating a test load adapted to be coupled between inputs of the digital voltmeter for replacing a component of the circuit under load; and

incorporating a switch adapted to short circuit test leads of the digital voltmeter through the test load.

14. The method of claim 13, further comprising coupling test leads of the voltmeter to the circuit under load.

15. The method of claim 14, further comprising dynamically testing the circuit under load to identify the type and location of circuit faults in the circuit under load.

16. The method of claim 14, further comprising jumping the leads together through the test load.

17. The method of claim 13, further comprising incorporating a variable test load in the voltmeter for applicability to different circuits under load.

18. The method of claim 13, further comprising incorporating a current limiting fuse or circuit breaker.

19. The method of claim 13, further comprising incorporating the switch for accessibility by a user/technician.

20. The method of claim 13, further comprising providing the test load as an equivalent load of a component removed from the circuit under load.

21. The method of claim 13, further comprising providing the test load as an artificial load of the circuit under load.

22. Circuitry for use in identifying a fault in a circuit under test, comprising:

a test load adapted to be coupled between test leads of a digital voltmeter; and

a switch adapted, when closed, to couple the test load between the test leads and, when opened, to decouple the test load from the test leads, wherein when the test leads are coupled to the circuit under test and the switch is closed, the test load replaces a component of the circuit under test.

23. The circuitry of claim 22, further comprising a fuse or circuit breaker adapted to help avoid a further fault in the circuit under test.

24. The circuitry of claim 22, wherein the test load is adapted to be in parallel with an input resistance of the voltmeter.

25. The circuitry of claim 22, wherein the test load is adapted to couple to the circuit under test for taking a voltage drop reading by the digital voltmeter across the test load when the switch is closed while the circuit under test is tested for identifying the type and location of the fault in the circuit under test.

26. The circuitry of claim 25, wherein the voltage is read when the test load is decoupled from the circuit under test also for identifying the type and location of the fault.

27. The circuitry of claim 22, wherein conventional test leads can be used with the voltmeter.

28. The circuitry of claim 22, wherein the test load and the switch are integrated in the voltmeter.

29. The circuitry of claim 28, wherein conventional test leads can be used with the voltmeter.

30. The circuitry of claim 22, wherein the test load comprises a resistor.

31. The circuitry of claim 22, wherein the test load is adapted to be coupled to complete the circuit under test where a component of the circuit under test has been removed.

32. The circuitry of claim 22, wherein the test load and the switch are adapted to help determine the-type and location of the fault by following a systematic procedure of testing the circuit under test that comprises combining the position where the test leads are coupled to the circuit under test and whether or not the test load is coupled between the test leads.

33. The circuitry of claim 22, wherein voltage readings obtained on the voltmeter with the test load coupled between the test leads comprise a nominal system voltage or a nearly nominal system voltage of the circuit under test, or a ghost reading upon loss of ground to the circuit under test.

34. The circuitry of claim 22, wherein the test load is adapted to replace a component in the circuit under test.

35. The circuitry of claim 22, wherein the test load is adapted to replace a fuse or circuit breaker in the circuit under test.

36. The circuitry of claim 22, wherein the test load is adapted to couple to the circuit under test and to be used in performing a dynamic voltage drop test rather than a static voltage test of the circuit under test.

37. The circuitry of claim 22, wherein the test load is adapted to provide a parallel voltage drop with the voltmeter.

38. The circuitry of claim 22, wherein interpretation of results of voltage readings with the voltmeter with or without the test load coupled between the test leads enables the fault to be located and its type identified in the circuit under test.

39. The circuitry of claim 22, wherein the test load is adapted to couple to the circuit under test for taking a voltage reading by the digital voltmeter across the test load when the test leads are coupled to the circuit under test in a procedure for identifying the type and location of the fault in the circuit under test.

40. The circuitry of claim 22, wherein the test load is adapted to decouple from the circuit under test for taking a voltage reading by the digital voltmeter when the test leads are coupled to the circuit under test in a procedure used for identifying the type and location of the fault in the circuit under test.

41. The circuitry of claim 22, wherein the test load is adapted to couple to the circuit under test in series with a corrosive fault in the circuit under test when the test leads are coupled to the circuit under test for finding a voltage reading by the digital voltmeter across the test load for isolating the corrosive fault in the circuit under test.

42. The circuitry of claim 22, wherein the test load is adapted to couple to the circuit under test for taking a voltage reading by the digital voltmeter across the test load when the test leads are coupled to the circuit under test not for measuring a resistive fault to ground.

43. The circuitry of claim 22, wherein the test load is adapted to couple to the circuit under test for taking a voltage reading by the digital voltmeter across the test load when the test leads are coupled to the circuit under test for locating a corrosive fault in the circuit under test.

44. Test leads for testing a circuit under test with a digital voltmeter, comprising:

a first test lead;

a second test lead; and

a load adapted to be switchably coupled between the first and second test leads such that, in one switchable state, the load completes the circuit under test, replacing a component of the circuit under test.