驗電器簡介

驗電器是(shi)(shi)(shi)一(yi)種檢(jian)測(ce)物體(ti)是(shi)(shi)(shi)否(fou)帶(dai)電(dian)(dian)(dian)以(yi)及粗略估(gu)計(ji)帶(dai)電(dian)(dian)(dian)量(liang)大小(xiao)(xiao)的(de)儀器，典型構造如(ru)左圖(tu)所(suo)示。當被檢(jian)驗物體(ti)接觸驗電(dian)(dian)(dian)器頂端的(de)導體(ti)時，自身所(suo)帶(dai)的(de)電(dian)(dian)(dian)荷(he)會傳到(dao)玻璃(li)鐘罩(zhao)內的(de)箔(bo)片(pian)(pian)(pian)上。由于同種電(dian)(dian)(dian)荷(he)相互排斥，箔(bo)片(pian)(pian)(pian)將(jiang)(jiang)自動分(fen)開，張成一(yi)定角(jiao)度(du)(du)(du)。根據兩箔(bo)片(pian)(pian)(pian)張成角(jiao)度(du)(du)(du)的(de)大小(xiao)(xiao)可估(gu)計(ji)物體(ti)帶(dai)電(dian)(dian)(dian)量(liang)的(de)大小(xiao)(xiao)。其實這是(shi)(shi)(shi)箔(bo)片(pian)(pian)(pian)所(suo)受電(dian)(dian)(dian)場力(li)包括(kuo)箔(bo)片(pian)(pian)(pian)上同名的(de)電(dian)(dian)(dian)荷(he)的(de)斥力(li)和器皿(min)內壁異(yi)名電(dian)(dian)(dian)荷(he)的(de)吸(xi)引力(li)。如(ru)果(guo)將(jiang)(jiang)玻璃(li)瓶改(gai)為使(shi)用金屬盒以(yi)便屏蔽(bi)靜電(dian)(dian)(dian)、金屬棒和器皿(min)引出導線以(yi)便測(ce)量(liang)兩點(dian)間電(dian)(dian)(dian)勢差、增加刻度(du)(du)(du)以(yi)便將(jiang)(jiang)結果(guo)量(liang)化，那么驗電(dian)(dian)(dian)器可以(yi)改(gai)造為更精確的(de)靜電(dian)(dian)(dian)計(ji)。

驗電器由法國的讓·安東尼·諾雷于1748年發明 。
上部是(shi)一(yi)金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)球(或者也有(you)用(yong)金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)板(ban))，它(ta)和(he)金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)桿(gan)相(xiang)連接(jie)(jie)，金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)桿(gan)穿過橡(xiang)皮(pi)塞， 其下端掛兩片極薄的(de)(de)(de)(de)(de)(de)金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)箔(bo)(bo)，封裝在玻璃瓶內。檢驗(yan)時(shi)，把物(wu)(wu)體(ti)與(yu)金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)球(金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)板(ban))接(jie)(jie)觸(chu)，如果物(wu)(wu)體(ti)帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，就有(you)一(yi)部分(fen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)傳到(dao)兩片金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)箔(bo)(bo)上，金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)箔(bo)(bo)由于帶(dai)(dai)(dai)了同(tong)種(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)，彼此排斥而張(zhang)開(kai)(kai)(kai)，所(suo)帶(dai)(dai)(dai)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)越(yue)多，張(zhang)開(kai)(kai)(kai)的(de)(de)(de)(de)(de)(de)角度越(yue)大；如果物(wu)(wu)體(ti)不帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，則金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)箔(bo)(bo)不動。當(dang)已知物(wu)(wu)體(ti)帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，若要識別它(ta)所(suo)帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)的(de)(de)(de)(de)(de)(de)種(zhong)類，只要先把這(zhe)帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)體(ti)與(yu)金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)球接(jie)(jie)觸(chu)一(yi)下，使金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)箔(bo)(bo)張(zhang)開(kai)(kai)(kai)。然后(hou)，再用(yong)已知的(de)(de)(de)(de)(de)(de)帶(dai)(dai)(dai)足夠多正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)物(wu)(wu)體(ti)接(jie)(jie)觸(chu)驗(yan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器的(de)(de)(de)(de)(de)(de)金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)球，如果金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)箔(bo)(bo)張(zhang)開(kai)(kai)(kai)的(de)(de)(de)(de)(de)(de)角度更(geng)大，則表(biao)示該帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)體(ti)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)為(wei)正(zheng)的(de)(de)(de)(de)(de)(de)；反之，如果金(jin)(jin)(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)(shu)箔(bo)(bo)張(zhang)開(kai)(kai)(kai)的(de)(de)(de)(de)(de)(de)角度減小(xiao)，或先閉合(he)而后(hou)張(zhang)開(kai)(kai)(kai)，則表(biao)示帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)體(ti)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)是(shi)負(fu)的(de)(de)(de)(de)(de)(de)。以上事實(shi)意(yi)味著，帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)體(ti)再增(zeng)加(jia)同(tong)種(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)的(de)(de)(de)(de)(de)(de)量值(zhi)增(zeng)大；帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)體(ti)再增(zeng)加(jia)異種(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)的(de)(de)(de)(de)(de)(de)量值(zhi)減小(xiao)。因(yin)此，人們(men)通常將(jiang)正(zheng)、負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)分(fen)別表(biao)示為(wei)正(zheng)值(zhi)和(he)負(fu)值(zhi)。例如。將(jiang)帶(dai)(dai)(dai)有(you)等量異種(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)的(de)(de)(de)(de)(de)(de)物(wu)(wu)體(ti)相(xiang)接(jie)(jie)觸(chu)，它(ta)們(men)所(suo)帶(dai)(dai)(dai)正(zheng)、負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)之代數和(he)為(wei)零，表(biao)現為(wei)對外的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)效應相(xiang)互抵消，宛如不帶(dai)(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)一(yi)樣(yang)。這(zhe)時(shi)，它(ta)們(men)呈電(dian)(dian)(dian)(dian)(dian)(dian)(dian)中(zhong)性。這(zhe)種(zhong)現象叫做放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)或電(dian)(dian)(dian)(dian)(dian)(dian)(dian)中(zhong)和(he)。