Ohmmeter

measuredtwo-terminal (2T) sensing
An ohmmeter is an electrical instrument that measures electrical resistance, the opposition to an electric current.wikipedia
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Measuring instrument

instrumentscientific instrumentinstruments
An ohmmeter is an electrical instrument that measures electrical resistance, the opposition to an electric current.
Ohmmeter

Electrical resistance and conductance

resistanceelectrical resistanceconductance
An ohmmeter is an electrical instrument that measures electrical resistance, the opposition to an electric current.
An instrument for measuring resistance is called an ohmmeter.

Multimeter

digital multimeterdigital multimetersmultitester
Ohmmeters of this type only ever measured resistance as they could not easily be incorporated into a multimeter design.
A multimeter is a combination of a multirange DC voltmeter, multirange AC voltmeter, multirange ammeter, and multirange ohmmeter.

Megger Group Limited

AVOEvershed & Vignoles LtdEvershed & Vignoles Ltd.
Megohmmeters (also a trademarked device Megger) measure large values of resistance.
Three other products were also nominated: hand-held micro-ohmmeter MOM2 (category Innovative Power Product of the Year), professional portable appliance tester PAT400 (Innovative Test & Measurement Product of the Year), and digital earth clamps DET14C / DET24C (Innovative Commercial/Industrial Product of the Year).

Four-terminal sensing

four terminal measurementKelvin connectionKelvin sensing
This four terminal measurement technique is called Kelvin sensing, after William Thomson, Lord Kelvin, who invented the Kelvin bridge in 1861 to measure very low resistances.
Four-terminal sensing (4T sensing), 4-wire sensing, or 4-point probes method is an electrical impedance measuring technique that uses separate pairs of current-carrying and voltage-sensing electrodes to make more accurate measurements than the simpler and more usual two-terminal (2T) sensing.

Electronic test equipment

test equipmentelectronic test instrumenttest
Electronic test equipment
Ohmmeter (Measures resistance)

Kelvin bridge

This four terminal measurement technique is called Kelvin sensing, after William Thomson, Lord Kelvin, who invented the Kelvin bridge in 1861 to measure very low resistances.
Resistors above about 1 ohm in value can be measured using a variety of techniques, such as an ohmmeter or by using a Wheatstone bridge.

Ammeter

microammetermoving coil meterampere-meter
Ammeter
This type of meter movement is extremely common for both ammeters and other meters derived from them, such as voltmeters and ohmmeters.

Megohmmeter

Megohmmeter
Megohmmeter or megger is a special type of ohmmeter used to measure the electrical resistance of insulators.

Electricity

electricalelectricelectrically
An ohmmeter is an electrical instrument that measures electrical resistance, the opposition to an electric current.

Electric current

currentcurrentselectrical current
An ohmmeter is an electrical instrument that measures electrical resistance, the opposition to an electric current.

Omega

ΩOmega (Ω)ω (omega)
The unit of measurement for resistance is ohms .

Galvanometer

tangent galvanometernull detectorgalvanoscope
These were similar to the galvanometer type movement encountered in later instruments, but instead of hairsprings to supply a restoring force they used conducting 'ligaments'.

Voltage

potential differenceVvoltages
Subsequent designs of ohmmeter provided a small battery to apply a voltage to a resistance via a galvanometer to measure the current through the resistance (battery, galvanometer and resistance all connected in series).

Series and parallel circuits

seriesparallelin series
Subsequent designs of ohmmeter provided a small battery to apply a voltage to a resistance via a galvanometer to measure the current through the resistance (battery, galvanometer and resistance all connected in series).

Microcontroller

microcontrollersMCUmicro-controller
These measurements are then digitized with an analog digital converter (adc) after which a microcontroller or microprocessor make the division of the current and voltage according to Ohm's Law and then decode these to a display to offer the user a reading of the resistance value they're measuring at that instant.

Microprocessor

microprocessorsprocessorchip
These measurements are then digitized with an analog digital converter (adc) after which a microcontroller or microprocessor make the division of the current and voltage according to Ohm's Law and then decode these to a display to offer the user a reading of the resistance value they're measuring at that instant.

Ohm's law

ohmicOhmohmic losses
These measurements are then digitized with an analog digital converter (adc) after which a microcontroller or microprocessor make the division of the current and voltage according to Ohm's Law and then decode these to a display to offer the user a reading of the resistance value they're measuring at that instant.

Current divider

current divisioncurrent divider rulereduced output
This is partly because the change in deflection itself is small when the resistance measured is too small in proportion to the intrinsic resistance of the ohmmeter (which can be dealt with through current division), but mostly because the meter's reading is the sum of the resistance of the measuring leads, the contact resistances and the resistance being measured.

William Thomson, 1st Baron Kelvin

William ThomsonLord KelvinKelvin
This four terminal measurement technique is called Kelvin sensing, after William Thomson, Lord Kelvin, who invented the Kelvin bridge in 1861 to measure very low resistances.

Electronics

electronicelectronic deviceelectronic equipment
Electronics

Electrical network

circuitelectrical circuitelectric circuit
Electric circuit

Chemiresistor

chemical sensorschemiresistivenanotubes
The resistance between the electrodes can be easily measured.