An apparatus is provided for a diagnostic circuit test device having multi-meter functionality and being adapted to provide current sourcing to an electrical system for selective measurement of a plurality of parameters thereof in powered and unpowered states. The diagnostic circuit test device comprises a conductive probe element configured to be placed into contact with the electrical system and provide an input signal thereto. A power supply is interconnected between an internal power source and the conductive probe element. Processors are electrically connected to the conductive probe element and configured to manipulate the input signal provided to the electrical system and receive an output signal in response to the input signal. The output signal is representative of at least one of the parameters of the electrical system. A display device is configured to display a reading of the output signal which is representative of the parameter.

A test lead assembly includes a first test lead having a first cable extending between a distal end and a proximal end, a first test probe attached to the distal end and a first plug attached to the proximal end; a second test lead having a second cable extending between a distal end and a proximal end, a second test probe attached to the distal end, and a second plug attached to the proximal end; and a fastener member for repeatedly releasably engaging at least a portion of the first cable with at least a portion of the second cable along a length of the first and second cables. The test lead assembly and a measurement device incorporating the test lead assembly can avoid or at least reduce knotting of the test leads.

A mechanism is disclosed for mitigating common mode current in a test and measurement device. A measurement current can be received from a device under test via a measurement lead that couples a transformer in the test and measurement device with the device under test. The test and measurement device can then be calibrated to apply a nulling current to cancel the common mode current from the measurement current. Other embodiments can be described and/or claimed herein.

A clamp meter is revealed. The clamp includes a pair of jaws disposed on a main body. The main body is arranged with a display panel and a plurality of buttons. The two jaws can be opened or closed by manual operation to get data of an object users intend to measure. The data is transferred to the main body and shown on the display panel. Users can switch to the electrical parameter they need by pressing the buttons. The clamp meter features on a plurality of indicator lights disposed on the jaws. Users can obtain current data directly by observing the indicator lights.

Techniques and mechanisms disclosed herein add dithering noise to a receiver to reduce harmonics.

Systems and methods provide measurement of alternating current (AC) electrical parameters in an insulated wire without requiring a galvanic connection between the insulated wire and a test probe. Measurement systems or instruments may include a housing that includes both a non-contact voltage sensor and a non-contact current sensor. The measurement system obtains measurements from the voltage sensor and the current sensor during a measurement time interval and processes the measurements to determine AC electrical parameters of the insulated wire. The AC electrical parameters may be presented to an operator via a visual indicator device (e.g., display, lights). The AC electrical parameters may additionally or alternatively be communicated to an external device via a wired and/or wireless communications interface. The measurement system may include an alignment feedback sensor that provides feedback to a user regarding the mechanical alignment of the insulated wire relative to the voltage sensor and the current sensor.

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.

Systems and methods of providing a magnetically coupled ground reference probe for use with test equipment, such as digital multimeters (DMMs). The magnetically coupled ground reference probes disclosed herein may be used instead of a typical test probe or alligator clip. A magnetically coupled ground reference probe may be provided which includes an insulative housing surrounding a conductive magnet such as a permanent magnet or an electromagnet. The magnet may autonomously retract into a cavity of the insulative housing when not coupled to a ground reference so that the magnet does not contact a high potential source when being handled by the operator. In at least some implementations, at least a portion of the insulation material of the housing may be compressible to allow the magnet to come into physical contact with a ground reference surface while providing a sufficient creepage and clearance path.

A measuring and analyzing device is described which comprises a housing, a spectrum analyzer unit for analyzing a spectrum of a signal received, and a multimeter unit for measuring currents, voltages, resistances and/or connectivities. Said housing encompasses said spectrum analyzer unit and said multimeter unit. Said device is a handheld and portable measuring and analyzing device. Further, a method for measuring and analyzing signals is described.

A multifunction testing and measuring device having a probe body with an elongated portion extending outward from a rearward main body portion to a hook-shaped forward end, the hook-shaped end useful for isolating a conductor under test, a slide closure member adapted to slide longitudinally forward from a rearward open position to a forward closed position, the closed position useful to capture the conductor under test within a space encircled by the combination of the hook-shaped end, the closed slide closure member, and the rearward main body, with the space encircled including a current sensing zone, and having test leads integral to and stowable on the main body. The multi tester comprises circuitry adapted for detecting a magnetic flux generated by an electric current passing through the conductor under test positioned within the current sensing zone, for sensing current and inrush current, as well as selectably measuring voltage, continuity, and resistance between the test leads.