{"product_id":"10k471-pakistan-varistor-10d471-10d471k-470-v","title":"10k471 Varistor 10d471 10d471k 470 v","description":"\u003cp\u003e470v 10k471 Varistor is non-linear resistor utilize a semiconductor electronic ceramic element mainly compose of Zinc Oxide and its resistor change as a function of the apply voltage. It s called Varistor or Transient surge absorber.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eWhat is a varistor?\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eA varistor is a voltage-dependent resistor (VDR). Its resistance is variable and depends on the voltage applied. Hence the word is compos of parts of the words “\u003cem\u003evar\u003c\/em\u003eiable res\u003cem\u003eistor\u003c\/em\u003e”. Their resistance decreases when the voltage increases.\u003c\/p\u003e\n\u003cp\u003eIn case of excessive voltage increases, their resistance drops dramatically. This behavior makes them suitable to protect circuits during voltage surges. Causes of a surge can include lightning strikes and electrostatic discharges. The most common type of VDR is the metal oxide varistor or MOV.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eDefinition:\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eVaristors are nonlinear two-element semiconductors that drop in resistance as voltage increases. Voltage-dependent resistor are often use as surge suppressor for sensitive circuits.\u003c\/p\u003e\n\u003cp\u003eHere are some examples of different packages that are often encounter. The block packages are use for higher power ratings.\u003c\/p\u003e\n\u003ctable border=\"0\" cellpadding=\"1\" cellspacing=\"1\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cimg alt=\"varistor\" aria-describedby=\"caption-attachment-570\" height=\"100\" src=\"https:\/\/digilog.pk\/cdn\/shop\/files\/varistor-disc.gif\" title=\"disc varistor\" width=\"100\" data-original=\"http:\/\/www.resistorguide.com\/pictures\/varistor-disc.gif\" loading=\"lazy\" data-files=\"varistor-disc.gif\"\u003e\n\u003cp id=\"caption-attachment-570\"\u003eDisc\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cimg alt=\"block MOV for industrial applications\" aria-describedby=\"caption-attachment-569\" height=\"100\" src=\"https:\/\/digilog.pk\/cdn\/shop\/files\/varistor-block.gif\" title=\"varistor block\" width=\"100\" data-original=\"http:\/\/www.resistorguide.com\/pictures\/varistor-block.gif\" loading=\"lazy\" data-files=\"varistor-block.gif\"\u003e\n\u003cp id=\"caption-attachment-569\"\u003eBlock\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cimg alt=\"a yellow radial leaded varistor\" aria-describedby=\"caption-attachment-571\" height=\"100\" src=\"https:\/\/digilog.pk\/cdn\/shop\/files\/varistor-radial-leaded.gif\" title=\"radial leaded\" width=\"100\" data-original=\"http:\/\/www.resistorguide.com\/pictures\/varistor-radial-leaded.gif\" loading=\"lazy\" data-files=\"varistor-radial-leaded.gif\"\u003e\n\u003cp id=\"caption-attachment-571\"\u003eRadial leaded\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cimg alt=\"An axial leaded varistor\" aria-describedby=\"caption-attachment-568\" height=\"100\" src=\"https:\/\/digilog.pk\/cdn\/shop\/files\/varistor-axial-leade.gif\" title=\"Axial leaded\" width=\"100\" data-original=\"http:\/\/www.resistorguide.com\/pictures\/varistor-axial-leade.gif\" loading=\"lazy\" data-files=\"varistor-axial-leade.gif\"\u003e\n\u003cp id=\"caption-attachment-568\"\u003eAxial leaded\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch2\u003e\n\u003cstrong\u003eCharacteristics of \u003c\/strong\u003e10k471 Varistor\u003cstrong\u003e:\u003c\/strong\u003e\n\u003c\/h2\u003e\n\u003cp\u003eA voltage-dependent resistor has a nonlinear varying resistance, dependent on the voltage applied. The impedance is high under nominal load conditions, but will sharply decrease to a low value when a voltage threshold,  the breakdown voltage, is exceed. They are often use to protect circuits against excessive transient voltage.\u003c\/p\u003e\n\u003cp\u003eWhen the circuit is exposed to a high voltage transient, the varistor starts to conduct and clamps the  voltage to a safe level. The energy of the incoming surge is partially conduct and partially absorb, protecting the circuit.\u003c\/p\u003e\n\u003cp\u003eThe most common type is the MOV, or metal oxide varistor. They are construct of a sinter matrix of zinc oxide (ZnO) grains. The grain boundaries provide P-N junction semiconductor characteristic, similar to a diode junction. The matrix of randomly oriented grains can be compare to a large network of diodes in series and parallel.\u003c\/p\u003e\n\u003cp\u003eWhen a low voltage is apply, only very little current flows, caused by the reverse leakage through the junctions. However, when a high voltage is apply, which exceeds the breakdown-voltage, the junction experience an breakdown and a large current can flow.\u003c\/p\u003e\n\u003ch4\u003eThe relationship between the current (I) through and the voltage (V) across the terminal, is typically described by:\u003c\/h4\u003e\n\u003cp\u003e\u003cimg align=\"bottom\" alt=\"\" src=\"https:\/\/chart.googleapis.com\/chart?cht=tx\u0026amp;chl=I=k%20%5Ctimes%20V%5E%5Calpha\"\u003e\u003c\/p\u003e\n\u003cp\u003eThe term α describes the degree of non-linearity.  Figure 1 shows the characteristic curves of a MOV(high α).\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.resistorguide.com\/types\/varistor\/varistor-curve-2\/\" rel=\"attachment wp-att-564\" title=\"Varistor characteristic curve »\" aria-label=\"Visit a webpage about Varistor characteristic curve »\"\u003e\u003cimg alt=\"varistor voltage-current characteristics\" src=\"https:\/\/digilog.pk\/cdn\/shop\/files\/varistor-curve1.png\" title=\"varistor characteristic curve\" data-original=\"http:\/\/www.resistorguide.com\/pictures\/varistor-curve1.png\" loading=\"lazy\" width=\"386\" height=\"257\" data-files=\"varistor-curve1.png\"\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eImportant selection parameters are the clamping voltage, peak current, maximum pulse energy, rated AC\/DC voltage and standby current. When used on communications lines, stray capacitance is also an important parameter. A high capacitance can act as a filter for high-frequency signals or induce crosstalk, limiting the available bandwidth of the communications line.\u003c\/p\u003e\n\u003cp\u003e470v 10k471 Varistor is non-linear resistors utilize a semiconductor electronic ceramic element mainly compose of Zinc Oxide and its resistor change as a function of the apply voltage. are useful for short duration protection in case of high transient voltage surges in the order of 1-1000 microseconds.\u003c\/p\u003e\n\u003cp\u003eThey are however not suit to handle sustain surges. If transient pulse energy in joules (J) is too high and significantly exceeds the absolute maximum ratings, they can melt, burn or explode.\u003c\/p\u003e\n\u003cp\u003eMOVs degrade when exposed to repeated surges. After each surge the MOVs voltage moves a little lower, how much depends on the joule rating of the MOV in relation to the pulse. As the clamping voltage falls lower and lower, a possible failure mode is a partial or complete short circuit, when the clamping voltage falls below the protected line voltage. This situation could lead to a fire hazard.\u003c\/p\u003e\n\u003cp\u003eTo prevent fire hazards, they are often connected in series with a thermal fuse which disconnect the MOV in case of overheating. To limit the degradation, it is advise to use an as high voltage as the protected circuit allows, to limit the amount of exposure to surges.\u003c\/p\u003e\n\u003ch2\u003e\n\u003cstrong\u003eApplications of \u003c\/strong\u003e 470v 10k471 Varistor\u003cstrong\u003e:\u003c\/strong\u003e\n\u003c\/h2\u003e\n\u003cp\u003eThe nonlinear characteristic of the varistor makes them ideal for use as surge protector devices. Sources of high voltage transients can, for example, be lightning strikes, electrostatic discharges or inductive discharge from motors or transformers. They are for example often used in surge protector power strips. Special types with low capacitance protect communication lines. These VDRs are useful for a wide variety of applications that can include:\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003eTelephone and other communication line protection\u003c\/li\u003e\n\u003cli\u003eRadio communication equipment transient suppression\u003c\/li\u003e\n\u003cli\u003eSurge protector power strips\u003c\/li\u003e\n\u003cli\u003eCable TV system surge protector\u003c\/li\u003e\n\u003cli\u003ePower supply protection\u003c\/li\u003e\n\u003cli\u003eMicroprocessor protection\u003c\/li\u003e\n\u003cli\u003eElectronics equipment protection\u003c\/li\u003e\n\u003cli\u003eLow voltage board-level protection\u003c\/li\u003e\n\u003cli\u003eTransient voltage surge suppressor (TVSS)\u003c\/li\u003e\n\u003cli\u003eCar electronic protection\u003c\/li\u003e\n\u003cli\u003eIndustrial high energy AC protection\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003ch2\u003e\u003cstrong\u003eTypes:\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThe most important types are:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eMetal oxide varistor – Described above, the MOV is composed of zinc oxide (ZnO)\u003c\/li\u003e\n\u003cli\u003eSilicon carbide varistor – At one time this was the most common type before the MOV came into the market. These components utilize silicon carbide (SiC). They have been intensively used in high power, high voltage applications. The disadvantage of these devices is that they draw a significant standby current, therefore a series gap is required to limit the standby power consumption.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cstrong\u003eAlternative types of surge suppressing devices include:\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eSelenium cells – These suppressors use selenium rectifiers allowing a high-energy reverse breakdown current. Some selenium cells have seal-healing properties that allow them to withstand high-energy discharges. They, however, do not have the clamping ability of modern MOVs.\u003c\/li\u003e\n\u003cli\u003eZener diodes – A transient suppression device that utilizes silicon rectifier technology. They have a very constant voltage-clamp ability. The major drawback of these components is that they have a limited energy dissipation capability.\u003c\/li\u003e\n\u003cli\u003eCrowbar devices – A crowbar device short-circuits a surge to ground, this short-circuit will continue until the current is below a certain very low level. Creating a lagging or power-follow effect. Examples of crowbar devices are:\n\u003cul\u003e\n\u003cli\u003eGas discharge tube (GDT) or spark gap – These devices conduct after a conducting spark is created, the disadvantage is that they take a relatively long time to trigger, the advantage is the large current carrying capabilities.\u003c\/li\u003e\n\u003cli\u003eThyristor surge protection device (TSPD) – have similar characteristics as a GDT, but can act much faster.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cstrong\u003eVaristor symbol\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThe following symbol is used for a varistor. It is depicted as a variable resistor which is dependent on voltage, U\u003cbr\u003e\u003cbr\u003eRead more \u003ca href=\"https:\/\/eepower.com\/resistor-guide\/resistor-types\/varistor\/\" title=\"Varistor | resistor types | resistor guide\" aria-label=\"Visit a webpage about Varistor | resistor types | resistor guide\"\u003ehttp:\/\/www.resistorguide.com\/varistor\/\u003c\/a\u003e\u003c\/p\u003e\n\u003ch2\u003e\n\u003cstrong\u003ePackage Includes for \u003c\/strong\u003e470v 10k471 Varistor\u003cstrong\u003e:\u003c\/strong\u003e\n\u003c\/h2\u003e\n\u003ch2\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e1 x  470v 10k471 Varistor\u003c\/p\u003e","brand":"Digilog Electronics","offers":[{"title":"Default Title","offer_id":43962406862913,"sku":"B188,L20,Th10","price":30.0,"currency_code":"PKR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0727\/2805\/1777\/files\/10K471_Varistor_10D471_10D471K_470_V_fcf2-eo.jpg?v=1779579998","url":"https:\/\/stem.pk\/products\/10k471-pakistan-varistor-10d471-10d471k-470-v","provider":"stem.pk","version":"1.0","type":"link"}