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Multimeter
A multimeter (also known as a multi-tester, volt-ohm-milliammeter, volt-ohmmeter or VOM, avometer or ampere-volt-ohmmeter) is a measuring instrument that can measure multiple electrical properties. A typical multimeter can measure voltage, electrical resistance, resistance, and electric current, current, in which case can be used as a voltmeter, ohmmeter, and ammeter. Some feature the measurement of additional properties such as temperature and capacitance. Analog multimeters use a microammeter with a moving pointer to display readings. Digital multimeters (DMMs) have numeric displays and are more precise than analog multimeters as a result. Meters will typically include probes that temporarily connect the instrument to the device or circuit under test, and offer some intrinsic safety features to protect the operator if the instrument is connected to high voltages that exceed its measurement capabilities. Multimeters vary in size, features, and price. They can be portable handh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avometer
AVOmeter is a British trademark for a line of multimeters and electrical measuring instruments; the brand is now owned by the Megger Group Limited. The first Avometer was made by the Automatic Coil Winder and Electrical Equipment Co. in 1923, and measured direct voltage, direct current and resistance. Possibly the best known multimeter of the range was the Model 8, which was produced in various versions from May 1951 until 2008; the last version was the Mark 7. The multimeter is often called simply an AVO, because the company logo carries the first letters of 'amps', 'volts' and 'ohms'. The design concept is due to the Post Office engineer Donald Macadie, who at the time of the introduction of the original AVOmeter in 1923 was a senior officer in the Post Office Factories Department in London. Technical features The original AVOmeter was designed to measure direct current (3 ranges, 0.12, 1.2 & 12 A), direct voltage (3 ranges, 12, 120 & 600 V) and resistance (single range, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltmeters
A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in Parallel circuit, parallel. It usually has a high Electrical resistivity and conductivity, 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. Voltmeters are made in a wide range of styles, some separately powered (e.g. by battery), and others powered by the measured voltage source itself. Instruments permanently mounted in a panel are used to monitor generators or other fixed apparatus. Portable instruments, usually equipped to also measure current and resistance in the form of a multimeter are standard test instrume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltmeter
A 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. Voltmeters are made in a wide range of styles, some separately powered (e.g. by battery), and others powered by the measured voltage source itself. Instruments permanently mounted in a panel are used to monitor generators or other fixed apparatus. Portable instruments, usually equipped to also measure current and resistance in the form of a multimeter are standard test instruments used in electrical and electronics work. Any meas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohmmeter
An analog ohmmeter An ohmmeter is an electrical instrument that measures electrical resistance (the opposition offered by a circuit or component to the flow of electric current). Multi-meters 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 . V=IR An ohmmeter should not be connected to a circuit or component that is carrying a current or is connected to a power source. Power should be disconnected before connecting the ohmmeter. Ohmmeters can be either connected in series or parallel based on requirements (whether resistance being measured is part of circuit or is a shunt resistance). Design evolution The first ohmmeters were based on a type of meter movement known as a 'ratiometer'. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammeter
An ammeter (abbreviation of ''ampere meter'') is an measuring instrument, instrument used to measure the electric current, current in a Electrical circuit, 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 Electrical resistance and conductance, 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''. Early ammeters were laboratory instruments that relied on the Earth's magnetic field for operation. By the late 19th century, improved instruments were designed which could be mounted in any position and allowed accurate measurements in electric power systems. It is generally represented by letter 'A' in a circuit. History The relatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amperes
The ampere ( , ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to 1 coulomb (C) moving past a point per second. It is named after French mathematician and physicist André-Marie Ampère (1775–1836), considered the father of electromagnetism along with Danish physicist Hans Christian Ørsted. As of the 2019 revision of the SI, the ampere is defined by fixing the elementary charge to be exactly , which means an ampere is an electric current equivalent to elementary charges moving every seconds, or approximately elementary charges moving in a second. Prior to the redefinition, the ampere was defined as the current passing through two parallel wires 1 metre apart that produces a magnetic force of newtons per metre. The earlier CGS system has two units of current, one structured similarly to the S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microammeter
An ammeter (abbreviation of ''ampere meter'') is an measuring instrument, instrument used to measure the electric current, current in a Electrical circuit, 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 Electrical resistance and conductance, 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''. Early ammeters were laboratory instruments that relied on the Earth's magnetic field for operation. By the late 19th century, improved instruments were designed which could be mounted in any position and allowed accurate measurements in electric power systems. It is generally represented by letter 'A' in a circuit. History The relatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MediaWiki
MediaWiki is free and open-source wiki software originally developed by Magnus Manske for use on Wikipedia on January 25, 2002, and further improved by Lee Daniel Crocker,mailarchive:wikipedia-l/2001-August/000382.html, Magnus Manske's announcement of "PHP Wikipedia", wikipedia-l, August 24, 2001 after which development has been coordinated by the Wikimedia Foundation. It powers several wiki hosting websites across the Internet, as well as most websites hosted by the Wikimedia Foundation including Wikipedia, Wiktionary, Wikimedia Commons, Wikiquote, Meta-Wiki and Wikidata, which define a large part of the set requirements for the software. Besides its usage on Wikimedia sites, MediaWiki has been used as a knowledge management and content management system on websites such as Fandom (website), Fandom, wikiHow and major internal installations like Intellipedia and Diplopedia. MediaWiki is written in the PHP programming language and stores all text content into a database. The sof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensitivity (electronics)
The sensitivity of an electronic device, such as a communications system receiver, or detection device, such as a PIN diode, is the minimum magnitude of input signal required to produce a specified output signal having a specified signal-to-noise ratio, or other specified criteria. In general, it is the signal level required for a particular quality of received information. In signal processing, sensitivity also relates to bandwidth and noise floor as is explained in more detail below. In the field of electronics different definitions are used for sensitivity. The IEEE dictionary states: "Definitions of sensitivity fall into two contrasting categories." It also provides multiple definitions relevant to sensors among which 1: "(measuring devices) The ratio of the magnitude of its response to the magnitude of the quantity measured.” and 2: "(radio receiver or similar device) Taken as the minimum input signal required to produce a specified output signal having a specified sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pifco Universal-Prüfer
Pifco (sometimes rendered PIFCO) is a British electrical goods brand and a former manufacturer of small domestic appliances. The company had a long history of acquisitions and was itself ultimately acquired in 2001 by US company Salton Group. The company came to an end in 2007, but the brand continued to be used and since 2021 has been owned by Sabichi, which has revived the brand. History Founding and growth The company was established as the ''Provincial Incandescent Fittings Co.'' in 1900 by Joseph Webber, who opened a single lock-up shop in Failsworth, Oldham, Greater Manchester. Formed as a limited company in 1902, the company initially sold gas lighting appliances and accessories such as burners and mantles. After World War I the company diversified into various electrical items. Christmas lights were an early addition to the product range, as were torches and battery lanterns. Hair dryers, shavers, fans and electric blankets soon followed. The company officially ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistance
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (), while electrical conductance is measured in siemens (S) (formerly called the 'mho' and then represented by ). The resistance of an object depends in large part on the material it is made of. Objects made of electrical insulators like rubber tend to have very high resistance and low conductance, while objects made of electrical conductors like metals tend to have very low resistance and high conductance. This relationship is quantified by resistivity or conductivity. The nature of a material is not the only factor in resistance and conductance, however; it also depends on the size and shape of an object because these properties are extensive rather tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
