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Calibrations
In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of known accuracy, a device generating the quantity to be measured such as a voltage, a sound tone, or a physical artifact, such as a meter ruler. The outcome of the comparison can result in one of the following: * no significant error being noted on the device under test * a significant error being noted but no adjustment made * an adjustment made to correct the error to an acceptable level Strictly speaking, the term "calibration" means just the act of comparison and does not include any subsequent adjustment. The calibration standard is normally traceable to a national or international standard held by a metrology body. BIPM Definition The formal definition of calibration by the International Bureau of Weights and Measures (BIPM) is the follo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard (metrology)
In metrology (the science of measurement), a standard (or etalon) is an object, system, or experiment that bears a defined relationship to a unit of measurement of a physical quantity. Standards are the fundamental reference for a system of weights and measures, against which all other measuring devices are compared. Historical standards for length, volume, and mass were defined by many different authorities, which resulted in confusion and inaccuracy of measurements. Modern measurements are defined in relationship to internationally standardized reference objects, which are used under carefully controlled laboratory conditions to define the units of length, mass, electrical potential, and other physical quantities. Hierarchy of standards There is a three-level hierarchy of physical measurement standards. At the top of the tree are the master standards – these are known as ''primary standards''. Primary standards are made to the highest metrological quality and are the definit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measurement
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the ''International vocabulary of metrology'' published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales. Measurement is a cornerstone of trade, science, technology and quantitative research in many disciplines. Historically, many measurement systems existed fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Certified Reference Materials
Certified reference materials (CRMs) are 'controls' or standards used to check the quality and metrological traceability of products, to validate analytical measurement methods, or for the calibration of instruments. A certified reference material is a particular form of measurement standard. Reference materials are particularly important for analytical chemistry and clinical analysis. Since most analytical instrumentation is comparative, it requires a sample of known composition (reference material) for accurate calibration. These reference materials are produced under stringent manufacturing procedures and differ from laboratory reagents in their certification and the traceability of the data provided. Quality management systems involving laboratory accreditation under national and international accreditation/certification standards such as ISO/IEC 17025 require metrological traceability to Certified Reference Materials (where possible) when using reference materials for ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Meter
A light meter is a device used to measure the amount of light. In photography, a light meter (more correctly an exposure meter) is used to determine the proper exposure for a photograph. The meter will include either a digital or analog calculator which displays the correct shutter speed and f-number for optimum exposure, given a certain lighting situation and film speed. Similarly, exposure meters are also used in the fields of cinematography and scenic design, in order to determine the optimum light level for a scene. Light meters are used in the general field of architectural lighting design to verify proper installation and performance of a building lighting system, and in assessing the light levels for growing plants. Use in photography The earliest type of light meters were called ''extinction meters'' and contained a numbered or lettered row of neutral density filters of increasing density. The photographer would position the meter in front of his subject and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geiger Counter
A Geiger counter (also known as a Geiger–Müller counter) is an electronic instrument used for detecting and measuring ionizing radiation. It is widely used in applications such as radiation dosimetry, radiological protection, experimental physics, nuclear industry and the Manumouthry. It detects ionizing radiation such as alpha particles, beta particles, and gamma rays using the ionization effect produced in a Geiger–Müller tube, which gives its name to the instrument. In wide and prominent use as a hand-held radiation survey instrument, it is perhaps one of the world's best-known radiation detection instruments. The original detection principle was realized in 1908 at the University of Manchester, but it was not until the development of the Geiger–Müller tube in 1928 that the Geiger counter could be produced as a practical instrument. Since then, it has been very popular due to its robust sensing element and relatively low cost. However, there are limitations in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionizing Radiation
Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel up to 99% of the speed of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum. Gamma rays, X-rays, and the higher energy ultraviolet part of the electromagnetic spectrum are ionizing radiation, whereas the lower energy ultraviolet, visible light, nearly all types of laser light, infrared, microwaves, and radio waves are non-ionizing radiation. The boundary between ionizing and non-ionizing radiation in the ultraviolet area is not sharply defined, as different molecules and atoms ionize at different energies. The energy of ionizing radiation starts between 10 electronvolts (eV) and 33 eV. Typical ionizing subatomic particles include alpha particles, beta particles, and neutrons. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intervalometer
An intervalometer, also called an interval meter or interval timer, is a device that measures short intervals of time. People commonly use such devices to signal, in accurate time intervals, the operation of some other device. The intervalometer measures the intermittent pulses between a starting pulse signal and an ending pulse signal, before a pulse counter measures the number of pulses released into the appropriate time interval. For instance, an intervalometer might activate something every 30 seconds. Photography Photographers use intervalometers to trigger exposures. Photographers often do this for a time-lapse series, or to take or begin taking picture after a set delay. Examples of intervalometer use in aerial photography include delaying the start of picture taking by an unattended camera until some time after takeoff and separating multiple exposures in time, and thus distance as the vehicle containing the camera travels, to obtain the 3D effect (stereoscopy). To ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise Dosimeter
A noise dosimeter (American English) or noise dosemeter (British English) is a specialized sound level meter intended specifically to measure the noise exposure of a person integrated over a period of time; usually to comply with Health and Safety regulations such as the Occupational Safety and Health (OSHA) 29 CFR 1910.95 Occupational Noise Exposure Standard or EU Directive 2003/10/EC. Noise Measurement Noise dosimeters measure and store sound pressure levels (SPL) and, by integrating these measurements over time, provide a cumulative noise-exposure reading for a given period of time, such as an 8-hour workday. Dosimeters can function as personal or area noise monitors. In occupational settings, personal noise dosimeters are often worn on the body of a worker with the microphone mounted on the middle-top of the person’s most exposed shoulder. Area monitoring can be used to estimate noise exposure when the noise levels are relatively constant and employees are not mobile. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Level Meter
A sound level meter (also called sound pressure level meter (SPL)) is used for acoustic measurements. It is commonly a hand-held instrument with a microphone. The best type of microphone for sound level meters is the condenser microphone, which combines precision with stability and reliability. The diaphragm of the microphone responds to changes in air pressure caused by sound waves. That is why the instrument is sometimes referred to as a sound pressure level meter (SPL). This movement of the diaphragm, i.e. the sound pressure (unit pascal, Pa), is converted into an electrical signal (unit volt, V). While describing sound in terms of sound pressure, a logarithmic conversion is usually applied and the sound pressure ''level'' is stated instead, in decibels (dB), with 0 dB SPL equal to 20 micropascals. A microphone is distinguishable by the voltage value produced when a known, constant root mean square sound pressure is applied. This is known as microphone sensitivity. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RF Probe
An RF probe is a device which allows electronic test equipment to measure radio frequency (RF) signal in an electronic circuit. History In 1980 Reed Gleason and Eric Strid invented the first high frequency wafer probe while working at Tektronix. They later went on to found Cascade Microtech in 1983. RF energy may be challenging to measure for one or more reasons, depending on the nature of the circuit to be measured and the measuring equipment at hand. The first kind of difficulty arises when the RF energy to be measured is at a frequency too high for available test equipment, such as a low-bandwidth oscilloscope, to process directly. In that case, the RF has to be converted to a DC or near-DC signal. In this situation, a simple probe type sometimes called an RF detector can be used to convert the RF signal to DC. Such device will work as a RF rectifier and give a pulsed DC voltage. The second kind of difficulty arises when RF energy has to be measured in a circuit which is se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic field, electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, Light, (visible) light, ultraviolet, X-rays, and gamma rays. All of these waves form part of the electromagnetic spectrum. Classical electromagnetism, Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric field, electric and magnetic fields. Depending on the frequency of oscillation, different wavelengths of electromagnetic spectrum are produced. In a vacuum, electromagnetic waves travel at the speed of light, commonly denoted ''c''. In homogeneous, isotropic media, the oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming a transverse wave. The position of an electromagnetic wave w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Accreditation Board For Testing And Calibration Laboratories
National Accreditation Board for Testing and Calibration Laboratories (NABL) provides accreditation to Conformity Assessment Bodies (Laboratories) in India. NABL Schemes include Accreditation (Recognition) of Technical competence of testing, calibration, medical testing laboratories, Proficiency testing providers (PTP) & Reference Material Producers (RMP) for a specific scope following ISO/IEC 17025, ISO 15189, ISO/IEC 17043 & ISO 17034:2016 Standards. It has Mutual Recognition Arrangement (MRA) with Asia Pacific Accreditation Cooperation (APAC), International Laboratory Accreditation Cooperation (ILAC). NABL is a constituent board of Quality Council of India which is an autonomous body setup under Department for Promotion of Industry and Internal Trade (DPIIT), Ministry of Commerce and Industry, Government of India. NABL provides accreditation in all major fields of Science and Engineering such as Biological, Chemical, Electrical, Electronics, Mechanical, Fluid-Flow, Non-Dest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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