干貨：壓敏電阻選型指南，收藏這一篇就夠了

一、壓敏電阻工作原理

目前，東沃電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)所供應的(de)壓敏電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)MOV，主要應用于(yu)低壓電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)浪涌(yong)保(bao)護，多(duo)為(wei)氧(yang)(yang)化鋅(xin)壓敏電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)。 它(ta)是以(yi)氧(yang)(yang)化鋅(xin)為(wei)主體(ti)，摻(chan)雜多(duo)種(zhong)金屬氧(yang)(yang)化物，采用典型的(de)電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)陶瓷(ci)工(gong)藝制成(cheng)的(de)多(duo)晶半導體(ti)陶瓷(ci)元器(qi)件。壓敏電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)具有對稱的(de)伏(fu)安特性(xing)曲線，流(liu)過(guo)MOV的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)隨MOV兩端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)壓的(de)增大呈指數規(gui)律增大。在(zai)(zai)實際應用過(guo)程中時(shi)(shi)(shi)，MOV一般并聯(lian)在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中，當電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)正常工(gong)作(zuo)時(shi)(shi)(shi)，它(ta)處于(yu)高(gao)(gao)阻(zu)狀態(tai)(tai)，不影響電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)正常工(gong)作(zuo)。當電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)出現異(yi)常瞬時(shi)(shi)(shi)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓 并達到(dao)其導通電(dian)(dian)(dian)(dian)(dian)(dian)壓（壓敏電(dian)(dian)(dian)(dian)(dian)(dian)壓）時(shi)(shi)(shi)，MOV迅速由(you)高(gao)(gao)阻(zu)狀態(tai)(tai)變為(wei)低阻(zu)狀態(tai)(tai)，泄放(fang)由(you)異(yi)常瞬時(shi)(shi)(shi)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓導致的(de)瞬時(shi)(shi)(shi)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，同時(shi)(shi)(shi)把異(yi)常瞬態(tai)(tai)過(guo)壓鉗制在(zai)(zai)一個(ge)安全水平之內(nei)，從而(er)保(bao)護后級電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)免遭異(yi)常瞬時(shi)(shi)(shi)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓的(de)損壞。

MOV具(ju)有較高的瞬時(shi)脈沖吸收(shou)能力，電(dian)(dian)容量較大(da)(da)，一般(ban)應(ying)用于(yu)(yu)AC 交流輸入端防雷保護。由于(yu)(yu)壓敏(min)電(dian)(dian)阻的浪涌吸收(shou)能力取決于(yu)(yu)它(ta)的物理尺寸，為此可通過制造(zao)不(bu)同(tong)大(da)(da)小(xiao)的MOV而獲得不(bu)同(tong)的瞬態(tai)浪涌電(dian)(dian)流值。 

目前，東沃電子所供應的壓敏電阻產品可分為七大類：

? 05D系列

? 07D系列

? 10D系列

? 14D系列

? 20D系列

? 25D系列

? 貼片系列

二、壓敏電阻特性特點

? 高浪(lang)(lang)涌(yong)吸(xi)收(shou)能力，多種浪(lang)(lang)涌(yong)吸(xi)收(shou)能力：標準、高浪(lang)(lang)涌(yong)、超(chao)高浪(lang)(lang)涌(yong)，壓敏電(dian)阻的物理尺寸決定其浪(lang)(lang)涌(yong)吸(xi)收(shou)能力；

? 響應速度快ns級

? 電壓(ya)范(fan)圍(wei)為(wei)18V~1800V，電壓(ya)精度通常為(wei)±10%，滿足低(di)壓(ya)到高壓(ya)的應用需求；

? MOV均為(wei)插件器件，尺寸多樣，東沃電子可提供直徑尺寸為(wei)5mm-53mm的MOV；

? 單(dan)體通流量(liang)可達到幾(ji)百安培至幾(ji)十(shi)千安培

?  一種老化型(xing)元器件，在大功率電源(yuan)端口保護時(shi)，常與氣體放(fang)電管串(chuan)聯使用(yong)，減緩老化，延(yan)長使用(yong)壽命；

?  寄(ji)生電容大(da)，在高頻(pin)信(xin)號系統(tong)中會引起高頻(pin)信(xin)號傳輸畸(ji)變；

三、壓敏電阻選型指南

1）壓(ya)(ya)(ya)(ya)敏(min)(min)電(dian)(dian)(dian)(dian)(dian)阻電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)值要大于實際電(dian)(dian)(dian)(dian)(dian)路中的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)峰值，即連續(xu)施(shi)加在壓(ya)(ya)(ya)(ya)敏(min)(min)電(dian)(dian)(dian)(dian)(dian)阻兩端的(de)電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)，要小于壓(ya)(ya)(ya)(ya)敏(min)(min)電(dian)(dian)(dian)(dian)(dian)阻規格(ge)書中的(de)“最大持續(xu)工作電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)值”；

2）壓(ya)敏電阻的(de)箝位電壓(ya)要小于(yu)被保護(hu)設備承受的(de)最大電壓(ya)；

3）壓敏電(dian)(dian)阻(zu)的(de)標稱放電(dian)(dian)電(dian)(dian)流(liu)要大于(yu)線路中(zhong)可能(neng)出現(xian)的(de)最大浪涌電(dian)(dian)流(liu)；

4）對于高(gao)頻率傳輸信號的(de)線路，電容要盡量的(de)小；

5）要考慮使用環境，具體要求的浪涌電壓(ya)情況；

具體還需(xu)要根據電路設(she)計(ji)需(xu)求來定奪，專業的事(shi)情找(zhao)專業的人做，少(shao)走(zou)彎(wan)路。壓敏電阻選型(xing)，東沃(wo)電子，免費提供(gong)選型(xing)服務(wu)。

四、壓敏電阻參數詳解

?  V_1mA：壓敏電壓，即壓敏電阻通過1mA電流時，壓敏電阻兩端的電壓； 

?  I_R：漏電流，一般是在83%的壓敏電壓下測得流過壓敏電阻的電流；

? V_AC：規定溫度下可連續施加MOV兩端的交流電壓； 

? V_DC：規定溫度下可連續施加在MOV兩端的直流電壓； 

? I_P：某一波形沖擊電流的峰值，MOV一般采用如圖5所示8/20μs電流波形進行測量；

? V_C：鉗位電壓，即在沖擊電流IP下MOV兩端的電壓；

? I_TM：不引起MOV失效，可單次施加規定波形脈沖的額定最大值；需要注意的是，ITM為破壞性測試，測試過ITM的MOV不建議在電路中使用；

五、壓敏電阻選型事項

1）壓(ya)敏電(dian)(dian)(dian)壓(ya)的選擇：在電(dian)(dian)(dian)路(lu)保護中，綜合多方面因(yin)素，東沃電(dian)(dian)(dian)子根(gen)據多年(nian)的工作經(jing)驗總結出，在交流(liu)(liu)電(dian)(dian)(dian)流(liu)(liu)中，要選用壓(ya)敏電(dian)(dian)(dian)壓(ya)為額(e)定電(dian)(dian)(dian)壓(ya)2.2~2.5倍(bei)的壓(ya)敏電(dian)(dian)(dian)阻(zu)；在直(zhi)流(liu)(liu)電(dian)(dian)(dian)路(lu)中，要選用壓(ya)敏電(dian)(dian)(dian)壓(ya)為直(zhi)流(liu)(liu)電(dian)(dian)(dian)壓(ya)額(e)定值1.8~2倍(bei)的壓(ya)敏電(dian)(dian)(dian)阻(zu)；

2）通流容(rong)(rong)量的選(xuan)擇(ze)(ze)：原(yuan)理上是按照最大暫態浪涌電(dian)流來選(xuan)擇(ze)(ze)，但在實(shi)際應用(yong)過程中，要適當加大所選(xuan)壓敏(min)電(dian)阻(zu)的通流容(rong)(rong)量。

3）固有寄生電(dian)容：壓(ya)敏電(dian)阻(zu)(zu)有一個固有電(dian)容問題，根(gen)據外形(xing)尺寸和標稱電(dian)壓(ya)的不同(tong)，其值在(zai)數百至(zhi)數千pF之間(jian)，不適合在(zai)高頻場合下使(shi)用(yong)。同(tong)時(shi)，壓(ya)敏電(dian)阻(zu)(zu)的瞬時(shi)功率較大，但平均持續功率卻很小，因此，不能讓壓(ya)敏電(dian)阻(zu)(zu)長時(shi)間(jian)處于工作狀態。

六、壓敏電阻典型應用

為了提高壓(ya)敏(min)(min)電(dian)(dian)阻(zu)(zu)(zu)(zu)的可靠性，壓(ya)敏(min)(min)電(dian)(dian)阻(zu)(zu)(zu)(zu)一(yi)般會配(pei)合陶瓷氣體(ti)放(fang)電(dian)(dian)管（GDT）或玻(bo)璃(li)氣體(ti)放(fang)電(dian)(dian)管（SPG）一(yi) 起(qi)使用，以減(jian)緩(huan)壓(ya)敏(min)(min)電(dian)(dian)阻(zu)(zu)(zu)(zu)的老化(hua)。GDT和SPG具有較高的脈沖擊(ji)穿(chuan)電(dian)(dian)壓(ya)和絕緣阻(zu)(zu)(zu)(zu)抗（100MΩ以上），在正(zheng)常使用條件下，GDT 或SPG與壓(ya)敏(min)(min)電(dian)(dian)阻(zu)(zu)(zu)(zu)串聯再并聯在被保(bao)護線(xian)路，這(zhe)樣壓(ya)敏(min)(min)電(dian)(dian)阻(zu)(zu)(zu)(zu)不(bu)會因為電(dian)(dian)網的波動或各(ge)種操作過電(dian)(dian)壓(ya)誤動作以引起(qi)壓(ya)敏(min)(min)電(dian)(dian)阻(zu)(zu)(zu)(zu)的老化(hua)。

欲想了解更多有關壓敏電阻應用知識，您身邊的被動器件供應廠商東沃電(dian)子，隨時隨地為您答疑解惑！