microfarad

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Related to Microfarads: picofarad, Nanofarad

microfarad

[¦mī·krō′far·əd]
(electricity)
A unit of capacitance equal to one-millionth of a farad. Abbreviated μF.
References in periodicals archive ?
A battery set is often placed at the capacitor is dependent on the power rating of the load and the allowable ripple voltage of the dc bus, and it is generally several thousands of microfarads. In the double-conversion three-arm AVR, the entire power demanded by the load must be converted twice (ac to dc and dc to ac), and the power electronic switches of two or three arms in a three-arm power converter are switched in high switching frequency.
The amount of capacitance needed to provide a large change in load current without very much voltage change for enough time for the converter to get up to speed, is substantial, often many thousands of microFarads.
(NYSE:VSH), Malvern, Pa., has released a new SMD tantalum capacitor with capacitance values up to 2200 microfarads; an inductor with DCR values down to 0.50 milliohms at 0.19 microhenries; and new zero crossing 1.5-kV/microsecond dV/dt phototriacs.
The epoxy layers between the voltage plate and ground plates are "between about 0.005 inches and about 0.009 inches" thick "to establish a large distributed capacitance of about 0.03 microfarads between the voltage plate and ground plates." The patent further states that "the close spacing of a voltage layer between two ground layers provides a large distributed capacitance (without requiring many discrete isolation capacitors) which inhibits switching signals from causing voltage spikes in the power lines [power bus noise]." Mupac shipped millions of dollars of wire wrap boards using the Leary construction prior to 1989.
The upscale BC27pi has over 200,000 microfarads of capacitance and a separate power supply and sells for $1395.