Abstract: A method and apparatus for testing batteries uses an audible voice prompt 35, 64 to enunciate the battery label or identifier that will be stored with the battery measurement in memory. Since the battery test technician must pay careful attention to the placement of the probes onto the battery terminal, the use of a voice prompt, rather than a visual prompt, allows the technician to keep his/her eyes on the test probes. If the label enunciated by the voice prompt does not match the label of the battery under test, the label on the tester can be reset to match the battery under test. In particular, a battery tester has a program which displays sequential numbers of battery labels that are stored with each battery's measurement data in memory. The sequence of labels corresponds to the sequential numbers marked on batteries in a string, array or matrix.

Abstract: An amplifying circuit comprises a differential input stage having a first input terminal, a second input terminal, and an intermediate node, wherein the differential input stage is configured to generate a differential current flowing through the intermediate node in response to an input voltage difference between the first and second input terminals. The amplifying circuit further comprises a first current source coupled to the intermediate node, which is configured to provide a first bias current which allows the differential current to vary within a predetermined range. The amplifying circuit further comprises an output terminal coupled to the intermediate node, and a second current source coupled to the intermediate node and configured to provide a second bias current. The second bias current compensates the differential current and the first bias current and produces an output current flowing through the output terminal in a predetermined direction. A measurement device is also described.

Abstract: A current sensing circuit comprises a first input terminal and a second input terminal for introducing a subject current from a device coupled between the first and second input terminals; a first amplifier having a first input node coupled to the first input terminal via a protection resistor, a second input node coupled to the second input terminal, and a first output node coupled to the first input node via a capacitor, wherein the first amplifier has a current sensing path for sensing the subject current and converting the subject current into an output voltage that changes with the subject current; and a protection circuit coupled between the first and second input nodes of the first amplifier, wherein the protection circuit is configured to draw a protection current from the first input terminal through the protection resistor to at least partially offset the subject current.

Abstract: The present invention relates to a method and an apparatus for generating an electronic test signal, and particularly to the use of such a method and apparatus for calibrating meters used to measure electrical characteristics such as voltage, current, phase angle and power. A user may select via a user input control the frequency domain characteristics of a desired electronic test signal including a user-defined set of amplitudes and phases of a fundamental frequency and one or more harmonic frequencies. A processor generates from the user-defined set of amplitudes and phases a frequency domain output set of amplitudes and phases for the fundamental frequency and one or more harmonic frequencies, which is then converted into a first time domain set of amplitudes extending over at least one cycle of the fundamental frequency. The first time domain set of amplitudes is communicated to a digital-to-analog output stage which generates an electronic test signal corresponding to the time domain set of amplitudes.

Abstract: The electronic calibration equipment for verifying the high frequency characteristics of electronic test equipment, including oscilloscopes arid time interval analyzers is provided.

Abstract: The present invention relates to electronic calibration equipment for verifying the high frequency characteristics of electronic test equipment, including oscilloscopes and time interval analyzers.