Shunt (electrical)A shunt is a device that is designed to provide a low-resistance path for an electrical current in a circuit. It is typically used to divert current away from a system or component in order to prevent overcurrent. Electrical shunts are commonly used in a variety of applications including power distribution systems, electrical measurement systems, automotive and marine applications. One example is in miniature Christmas lights which are wired in series.
AmmeterAn ammeter (abbreviation of Ampere meter) is an instrument used to measure the current in a circuit. Electric currents are measured in amperes (A), hence the name. For direct measurement, the ammeter is connected in series with the circuit in which the current is to be measured. An ammeter usually has low resistance so that it does not cause a significant voltage drop in the circuit being measured. Instruments used to measure smaller currents, in the milliampere or microampere range, are designated as milliammeters or microammeters.
OhmmeterAn ohmmeter is an electrical instrument that measures electrical resistance (the opposition offered by a circuit or component to the flow of electric current). Multimeters also function as ohmmeters when in resistance-measuring mode. An ohmmeter applies current to the circuit or component whose resistance is to be measured. It then measures the resulting voltage and calculates the resistance using Ohm’s law . An ohmmeter should not be connected to a circuit or component that is carrying a current or is connected to a power source.
VoltmeterA voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel. It usually has a high resistance so that it takes negligible current from the circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage measured and can be built from a galvanometer and series resistor. Meters using amplifiers can measure tiny voltages of microvolts or less. Digital voltmeters give a numerical display of voltage by use of an analog-to-digital converter.
GalvanometerA galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. A galvanometer works by deflecting a pointer in response to an electric current flowing through a coil in a constant magnetic field. Galvanometers can be thought of as a kind of actuator. Galvanometers came from the observation, first noted by Hans Christian Ørsted in 1820, that a magnetic compass's needle deflects when near a wire having electric current.
Electronic test equipmentElectronic test equipment is used to create signals and capture responses from electronic devices under test (DUTs). In this way, the proper operation of the DUT can be proven or faults in the device can be traced. Use of electronic test equipment is essential to any serious work on electronics systems. Practical electronics engineering and assembly requires the use of many different kinds of electronic test equipment ranging from the very simple and inexpensive (such as a test light consisting of just a light bulb and a test lead) to extremely complex and sophisticated such as automatic test equipment (ATE).
List of measuring instrumentsA measuring instrument is a device to measure a physical quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study and the referenced unit of measurement. Measuring instruments, and formal test methods which define the instrument's use, are the means by which these relations of numbers are obtained.
OhmThe ohm (symbol: Ω, the uppercase Greek letter omega) is the unit of electrical resistance in the International System of Units (SI). It is named after German physicist Georg Simon Ohm. Various empirically derived standard units for electrical resistance were developed in connection with early telegraphy practice, and the British Association for the Advancement of Science proposed a unit derived from existing units of mass, length and time, and of a convenient scale for practical work as early as 1861.
MetrologyMetrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in France when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based metric system in 1795, establishing a set of standards for other types of measurements.
Wheatstone bridgeA Wheatstone bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component. The primary benefit of the circuit is its ability to provide extremely accurate measurements (in contrast with something like a simple voltage divider). Its operation is similar to the original potentiometer. The Wheatstone bridge was invented by Samuel Hunter Christie (sometimes spelled "Christy") in 1833 and improved and popularized by Sir Charles Wheatstone in 1843.
