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Current sensing is a critical function in electronic systems but comes with complexities that are often underestimated. Accurately measuring current flow is not nearly as easy as measuring voltage and is even more difficult when trying to measure the current flowing through a load connected to relatively high-power supply voltages. Current sense resistors, also called shunt resistors, like Microhm Electronics MPR series, MVR series, MMS series are the technology of choice for measuring current flow due to their high measureme...
Date：2019-10-25 [More+]
Film resistor consist of Metal Film, Carbon Film and Metal Oxide Film resistor types, which are generally made by depositing pure metals, such as nickel, or an oxide film, such as tin-oxide, onto an insulating ceramic rod or substrate. The resistive value of the resistor is controlled by increasing the desired thickness of the deposited film giving them the names of either thick-film resistors or thin-film resistors. Metal Film Resistors have much better temperature stability than their carbon equivalents, lower noise and are...
Date：2019-10-23 [More+]
Noise is an unwanted wide spectrum signal that may be superimposed on any useful signal, including DC. Resistors, like other passive components, are noise sources to various degrees, depending upon resistance value, temperature, applied voltage, and resistor type. In high-end audio equipment, careful selection of resistors is one of the best ways to avoid or minimize noise and distortion in the signal path. Many experiments have been done to show why some resistors are noisier than others. But the only test that audio experts...
Date：2019-10-23 [More+]
Wirewound power resistors are usually rated with respect to continuous power, which can be insufficient for e-mobility applications. A typical application is the pre- and discharge of large capacitors, often referred to as soft start. In this case the pulse-handling capability of the resistor is also very important. This capability can be determined over a large range of pulse durations by combining theoretical basics with finite element simulations of the respective thermal performance. The results can be generalized so that...
Date：2019-10-22 [More+]
Wirewound resistors can be as good as 0.005% with their initial tolerance, with a TCR (temperature coefficient of resistance) as low as 5 ppm/C typical but usually about 15 to 25 ppm/C. Thermal noise is low and tracking to 2 ppm/C over a limited temperature range is possible, though it adds considerable cost. Microhm Electronicss KSW precision resistor has a tolarance 0.005％ and 5 ppm /C. There are certain important manufacturing factors that affect wirewound resistor properties. For example, the wire is wound under tension...
Date：2019-10-21 [More+]
Seismographic systems - the most widely used method in exploring for oil and gas and detecting earthquakes and tsunamis - utilize a surface shock energy source such as explosives, weight dropping, or gas guns to introduce a wave front into the earth. The effect is similar to creating a small, controlled earthquake. The digital seismic equipment that amplifies and records reflected seismic signals on a wideband receiver and tape drive in the field utilizes matched and discrete surface-mount foil resistors. MPR series, NMS4527,...
Date：2019-10-21 [More+]
All variable resistor modules include a specification for a their maximum power or current. The limitation maybe imposed by the switch rating, the voltage rating or the power rating of the resistors used in the design. Microhm Electronics not only provide variable resistor but also manufacture various fixed resistors. The issue can be complicated because if for example the resistor is supplied with a constant current the power dissipated will vary, and the situation will be different if a constant voltage is applied. In parti...
Date：2019-10-17 [More+]
Ammeter shunt resistor operation is well-understood. Used extensively for current measurement in the past, the resistors are used to shunt most of the current around the measurement instrument. This technique allows measurement of greater currents than is possible using normal ammeters. The low-value resistor is situated in series with the load, creating a small voltage drop across the resistor, which can be measured using a voltmeter. The current is then calculated using Ohms law. Modern ammeter shunts are a bit more complex...
Date：2019-10-12 [More+]
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