---
title: "List of measuring instruments"
chunk: 2/5
source: "https://en.wikipedia.org/wiki/List_of_measuring_instruments"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:29:33.241775+00:00"
instance: "kb-cron"
---

=== Electric field (negative gradient of electric potential, voltage per length) ===
Field mill

=== Magnetic field ===
See also the relevant section in the article about the magnetic field.

Compass
Hall effect sensor
Magnetometer
Proton magnetometer
SQUID
For the ranges of magnetic field see: Orders of magnitude (magnetic field)

=== Combination instruments ===
Multimeter, combines the functions of ammeter, voltmeter, and ohmmeter as a minimum.
LCR meter, combines the functions of ohmmeter, capacitance meter, and inductance meter.  Also called component bridge due to the bridge circuit method of measurement.

== Thermodynamics ==
Temperature-related considerations dominate thermodynamics. There are two distinct thermal properties: A thermal potential — the temperature. For example: A glowing coal has a different thermal quality than a non-glowing one.
And a substance-like property, — the entropy; for example: One glowing coal won't heat a pot of water, but a hundred will.
Energy in thermodynamics is calculated by multiplying the thermal potential by the amount of entropy found at that potential:  temperature times entropy.
Entropy can be created by friction but not annihilated.

=== Amount of substance ===
A physical quantity introduced in chemistry; usually determined indirectly. If mass and substance type of the sample are known, then atomic- or molecular masses (taken from a periodic table, masses measured by mass spectrometry) give direct access to the value of the amount of substance. (See also Molar mass.)  If specific molar values are given, then the amount of substance of a given sample may be determined by measuring volume, mass, or concentration. See also the subsection below about the measurement of the boiling point.
Gas collecting tube gases

=== Temperature ===
Electromagnetic spectroscopy
Galileo thermometer
Gas thermometer principle: relation between temperature and volume or pressure of a gas (gas laws).
Constant pressure gas thermometer
Constant volume gas thermometer
Liquid crystal thermometer
Liquid thermometer principle: relation between temperature and volume of a liquid (coefficient of thermal expansion).
Alcohol thermometer
Mercury-in-glass thermometer
Pyranometer principle: solar radiation flux density relates to surface temperature (Stefan–Boltzmann law)
Pyrometers principle: temperature dependence of spectral intensity of light (Planck's law), i.e. the color of the light relates to the temperature of its source, range: from about −50 °C to +4000 °C, note: measurement of thermal radiation (instead of thermal conduction, or thermal convection) means: no physical contact becomes necessary in temperature measurement (pyrometry). Also note: thermal space resolution (images) found in thermography.
Resistance thermometer principle: relation between temperature and electrical resistance of metals (platinum) (electrical resistance), range: 10 to 1,000 kelvins, application in physics and industry
Solid thermometer principle: relation between temperature and length of a solid (coefficient of thermal expansion).
Bimetallic strip
Thermistors principle: relation between temperature and electrical resistance of ceramics or polymers, range: from about 0.01 to 2,000 kelvins (−273.14 to 1,700 °C)
Thermocouples principle: relation between temperature and voltage of metal junctions (Seebeck effect), range: from about −200 °C to +1350 °C
Thermometer
Thermopile is a set of connected thermocouples
Triple point cell used for calibrating thermometers.

==== Imaging technology ====
Thermographic camera uses a microbolometer for detection of heat radiation.
See also Temperature measurement and Category:Thermometers. More technically related may be seen thermal analysis methods in materials science.
For the ranges of temperature-values see: Orders of magnitude (temperature)

=== Energy carried by entropy or thermal energy ===

This includes thermal mass or temperature coefficient of energy, reaction energy, heat flow, ...
Calorimeters are called passive if gauged to measure emerging energy carried by entropy, for example from chemical reactions. Calorimeters are called active or heated if they heat the sample, or reformulated: if they are gauged to fill the sample with a defined amount of entropy.

Actinometer heating power of radiation.
Constant-temperature calorimeter, phase change calorimeter for example an ice calorimeter or any other calorimeter observing a phase change or using a gauged phase change for heat measurement.
Constant-volume calorimeter, also called bomb calorimeter
Constant-pressure calorimeter, enthalpy-meter, or coffee cup calorimeter
Differential Scanning Calorimeter
Reaction calorimeter
See also Calorimeter or Calorimetry

=== Entropy ===
Entropy is accessible indirectly by measurement of energy and temperature.

==== Entropy transfer ====
Phase change calorimeter's energy value divided by absolute temperature give the entropy exchanged. Phase changes produce no entropy and therefore offer themselves as an entropy measurement concept. Thus entropy values occur indirectly by processing energy measurements at defined temperatures, without producing entropy.

Constant-temperature calorimeter, phase change calorimeter
Heat flux sensor uses thermopiles (which are connected thermocouples) to determine current density or flux of entropy.

==== Entropy content ====
The given sample is cooled down to (almost) absolute zero (for example by submerging the sample in liquid helium). At absolute zero temperature any sample is assumed to contain no entropy (see Third law of thermodynamics for further information). Then the following two active calorimeter types can be used to fill the sample with entropy until the desired temperature has been reached: (see also Thermodynamic databases for pure substances)

Constant-pressure calorimeter, enthalpy-meter, active
Constant-temperature calorimeter, phase change calorimeter, active

==== Entropy production ====
Processes transferring energy from a non-thermal carrier to heat as a carrier do produce entropy (Example: mechanical/electrical friction, established by Count Rumford).
Either the produced entropy or heat are measured (calorimetry) or the transferred energy of the non-thermal carrier may be measured.

calorimeter
(any device for measuring the work which will or would eventually be converted to heat and the ambient temperature)
Entropy lowering its temperature—without losing energy—produces entropy (Example: Heat conduction in an isolated rod; "thermal friction").

calorimeter

=== Temperature coefficient of energy or "heat capacity" ===
Concerning a given sample, a proportionality factor relating temperature change and energy carried by heat. If the sample is a gas, then this coefficient depends significantly on being measured at constant volume or at constant pressure. (The terminology preference in the heading indicates that the classical use of heat bars it from having substance-like properties.)

Constant-volume calorimeter, bomb calorimeter
Constant-pressure calorimeter, enthalpy-meter