Abstract: An electrical test instrument includes a built-in, switchable intermediate-voltage power source that enables line-leakage and run testing to be carried-out under higher-than-normal DUT operating voltages.

Abstract: A multiple function safety compliance test instrument includes a high voltage output switching relay protected by a solid state in-line circuit breaker.

Abstract: A high voltage switching matrix for selectively connecting a plurality of different voltage/current sources or inputs with a plurality of different outputs includes a common or shared relay for each of the voltage/current sources at the voltage/current source inputs rather than at the output ports.

Abstract: A safety compliance test instrument includes a display capable of displaying prompts, a menu display program, software for displaying a plurality of instrument verification menus, prompts, and messages concerning results of the verification tests, and software for enabling or preventing safety compliance tests from being performed depending on results of the verification. The safety compliance instrument includes at least two different safety compliance tests involving different connections to a device under test. The tests may be selected from the group consisting of a continuity test, a ground test, a dielectric withstand test, and an insulation resistance test, and more specifically from the group consisting of a continuity test, a ground bond test, AC and DC dielectric withstand tests, and an insulation test.

Abstract: A safety compliance test instrument includes a display capable of displaying prompts, a menu display program, software for displaying a plurality of instrument verification menus, prompts, and messages concerning results of the verification tests, and software for enabling or preventing safety compliance tests from being performed depending on results of the verification. The safety compliance instrument includes at least two different safety compliance tests involving different connections to a device under test. The tests may be selected from the group consisting of a continuity test, a ground test, a dielectric withstand test, and an insulation resistance test, and more specifically from the group consisting of a continuity test, a ground bond test, AC and DC dielectric withstand tests, and an insulation test.

Abstract: A test circuit for a withstand voltage tester, which includes a high voltage source, an overload-protective current detection device having one end connected to the high voltage source and an opposite end connected to the sample to be tested, and a second current detection device connected to the circuit of the high voltage source and the overload-protective current detection device, the second current detection device having a switch connected to the high voltage source, and detector means connected to ground to detect a high voltage, such that when the human body touches the test circuit and receives a high voltage through the ground, the detector means detects the presence of the high voltage, and outputs a signal to the switch upon such detection, causing the switch to cut off the circuit between the high voltage source and the test sample.

Abstract: An electrical run test instrument having a connection to a device under test includes a line voltage input, a high voltage input, and a high voltage switching matrix that enables selective connections between the device under test and line voltage or high voltage inputs using the same test set-up. The high voltage input may be interconnected with a safety compliance test instrument, permitting both run tests and line tests to be performed in succession using the same basic connection to the device under test.

Abstract: An electrical test instrument includes an improved operator interface capable of including the following features: (i) a pause/prompt feature enable prompts to be displayed during a pause, in order to facilitate operator reconfiguration of the instrument during testing; (ii) an autocalibration alert function to alert the operator that the instrument requires calibration; (iii) a security function that enables the operator to select from among a plurality of security level options; and (iv) a more flexible menu structure that enables set-up of additional tests performed by plug-in test instrument modules.

Abstract: A safety compliance test instrument includes circuitry for performing insulation resistance and ground circuit tests such as a ground bond test, as well as high voltage AC and DC dielectric withstand or hipot tests. A micro-processor based controller provides control signals to a common power circuit, and accepts input of test parameters for all four tests through an integrated user interface including a keypad and menu display.

Abstract: A leakage tester includes multiple circuits capable of simulating the impedance of the human body to electrical current under a variety of conditions, and in which the multiple circuits can be selected using a single menu-based operator interface for testing both normal-line and single-fault conditions such as open-neutral, reversed-line, and open-ground conditions, as well as for performing additional types of safety compliance tests including dielectric withstand, insulation resistance, and ground bond or continuity tests, in any sequence.

Abstract: Prior to beginning a dielectric withstand (leakage current) or insulative impedance test, but after applying the high voltage that will be used in the test, the temporary charging currents resulting from application of the high voltage are measured and analyzed to determine if the test sample is properly connected to the test apparatus. If no charging currents are measured, or if the insulation resistance is too high, then it is determined that the test sample is not properly connected and the test is terminated.

Abstract: An output open circuit test method including the steps of inputting the data of a predetermined charging current upper limit value and a predetermined test voltage and a predetermine test charging current time zone into a test apparatus, then employing a high voltage to the test sample, and then driving the test apparatus to measure the current between two ends of the test sample and to compare the measured current value with the predetermined charging current upper limit value, and then letting the test apparatus to start testing the leakage current of the test sample when the measured current value is below the predetermined charging current upper limit value.

Abstract: The invention employs a pair of known resistors which are permanently connected to the input terminals to which the unknown resistor may be connected. A source of d.c. voltage is connected to one input terminal and the voltage drops produced across each known resistor are alternately sampled and supplied to an A/D converter which converts these voltage drops into corresponding digital signals. A microprocessor computes the quantity VR1/VR2-1 where VR1 is the voltage drop across one known resistor and VR2 is the voltage drop across the other known resistor. The computed quantity is a linear function of the value of the unknown resistance. This computed quantity may then be converted to a corresponding analog signal and supplied to a meter. Since no switches are connected across the unknown resistor, leakage problems normally associated with extremely high resistance measurements are virtually eliminated and very high resistances in the order of 5000-10,000 megohms may be accurately measured and displayed.