產品概述
直讀介質損耗測試儀工作原理
1.“Q"的定義
Q表是根(gen)據串聯諧(xie)振(zhen)原理設(she)計,以諧(xie)振(zhen)電壓(ya)的比值來(lai)定位(wei)Q值。
“Q"表示元件或(huo)系(xi)統的“品質因數(shu)",其物(wu)理含(han)義是在一個振蕩(dang)周(zhou)期內(nei)貯存的能量(liang)與損耗的能量(liang)之比。對(dui)于電抗元件(電感或(huo)電容)來說,即在測試頻率上呈(cheng)現的電抗與電阻之比。
電容器容量的測量
A. 在(zai)測量范圍內的小于主調(diao)電(dian)容(rong)量的電(dian)容(rong)器(qi)的測量
a.選一個適當(dang)的諧振(zhen)電感(gan)接到(dao)“Lx"的兩端;
b.將調(diao)諧電(dian)容(rong)器調(diao)到(dao)最大值(zhi)附(fu)(fu)近,令這個(ge)電(dian)容(rong)是C1,如未(wei)知電(dian)容(rong)是小數值(zhi)的,C1應(ying)調(diao)到(dao)較小電(dian)容(rong)值(zhi)附(fu)(fu)近,以(yi)便達到(dao)盡(jin)可(ke)能高的分辨率(lv);
c.調訊號(hao)源的(de)頻(pin)率,使測試(shi)回路諧(xie)(xie)振,令諧(xie)(xie)振器Q的(de)讀數(shu)為Q1;
d.將被測(ce)電(dian)容(rong)接在“Cx"兩端(duan),調節調諧(xie)電(dian)容(rong)器(qi),使(shi)測(ce)試電(dian)路再諧(xie)振,令新的(de)調諧(xie)電(dian)容(rong)值(zhi)(zhi)為C2和指(zhi)示Q值(zhi)(zhi)為Q2。
被測電容的有效電容為:Cx= C1-C2
電容器損(sun)耗角正切為:
電容器(qi)的有效并(bing)聯電阻為:
C0為回路諧振(zhen)電感的自身(shen)電容。
B.大于(yu)調(diao)諧電(dian)容量的電(dian)容器用可替代法(fa)測量
a. 取一只(zhi)適(shi)當容(rong)量的標準電容(rong)量,其容(rong)量為(wei)C3,將它接(jie)在“Cx"接(jie)線柱上;
b.按5A/a-c各測試步驟;
c.取(qu)下標準電(dian)容(rong)器,將被(bei)測電(dian)容(rong)接到(dao)“Cx"接線柱,調(diao)節調(diao)諧(xie)電(dian)容(rong)器到(dao)諧(xie)振,此(ci)時主調(diao)電(dian)容(rong)量讀數為C2,則(ze)Cx可由下式得到(dao):
固體:白云石:8; 鹽:6; 醋酸纖維素:3.7-7.5; 瓷器:5-7; 纖維素:3.9; 米及谷類:3-5; 砂:3-5;砂糖:3; 玻璃:3.7; 硫磺:3.4; 瀝青:2.7; 聚四氟乙烯塑料:1.8-2.2; 紙:2; 云母:6-8
氣態:空氣及其(qi)他氣體(ti):1-1.2介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)是相對(dui)(dui)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)與真空中(zhong)絕對(dui)(dui)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)乘積。如果有高(gao)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)的(de)材料(liao)放(fang)在(zai)(zai)(zai)(zai)電(dian)(dian)(dian)(dian)(dian)場(chang)中(zhong),電(dian)(dian)(dian)(dian)(dian)場(chang)的(de)強(qiang)度(du)會在(zai)(zai)(zai)(zai)電(dian)(dian)(dian)(dian)(dian)介(jie)(jie)(jie)質(zhi)(zhi)(zhi)(zhi)(zhi)內有可觀的(de)下降。理想(xiang)導體(ti)的(de)相對(dui)(dui)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)為無窮大。一個(ge)電(dian)(dian)(dian)(dian)(dian)容板(ban)中(zhong)充入介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)為ε的(de)物質(zhi)(zhi)(zhi)(zhi)(zhi)后電(dian)(dian)(dian)(dian)(dian)容變(bian)大εr倍。電(dian)(dian)(dian)(dian)(dian)介(jie)(jie)(jie)質(zhi)(zhi)(zhi)(zhi)(zhi)有使空間(jian)(jian)比起實際尺(chi)寸變(bian)得更(geng)大或更(geng)小(xiao)的(de)屬性(xing)。例如,當一個(ge)電(dian)(dian)(dian)(dian)(dian)介(jie)(jie)(jie)質(zhi)(zhi)(zhi)(zhi)(zhi)材料(liao)放(fang)在(zai)(zai)(zai)(zai)兩個(ge)電(dian)(dian)(dian)(dian)(dian)荷之間(jian)(jian),它(ta)會減少作用在(zai)(zai)(zai)(zai)它(ta)們之間(jian)(jian)的(de)力,就像(xiang)它(ta)們被移(yi)遠了一樣(yang)。當電(dian)(dian)(dian)(dian)(dian)磁波(bo)穿過電(dian)(dian)(dian)(dian)(dian)介(jie)(jie)(jie)質(zhi)(zhi)(zhi)(zhi)(zhi),波(bo)的(de)速度(du)被減小(xiao),有更(geng)短的(de)波(bo)長(chang)。根據物質(zhi)(zhi)(zhi)(zhi)(zhi)的(de)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)可以判別高(gao)分子材料(liao)的(de)極性(xing)大小(xiao)。通常(chang),相對(dui)(dui)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)大于3.6的(de)物質(zhi)(zhi)(zhi)(zhi)(zhi)為極性(xing)物質(zhi)(zhi)(zhi)(zhi)(zhi);相對(dui)(dui)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)在(zai)(zai)(zai)(zai)2.8~3.6范圍內的(de)物質(zhi)(zhi)(zhi)(zhi)(zhi)為弱極性(xing)物質(zhi)(zhi)(zhi)(zhi)(zhi);相對(dui)(dui)介(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)常(chang)數(shu)(shu)(shu)(shu)小(xiao)于2.8為非極性(xing)物質(zhi)(zhi)(zhi)(zhi)(zhi)。
直讀介質損耗測試儀測試注意事項
1.本(ben)儀器應水平安放。
2.如果你(ni)需要較精確地測量,請(qing)接通電源后,預熱30分鐘。
3.調(diao)節主調(diao)電容數(shu)碼(ma)開(kai)關時,當(dang)接近(jin)諧(xie)振點時請緩(huan)調(diao)。
4.被測件和測試(shi)電路接(jie)(jie)線(xian)柱(zhu)間的(de)接(jie)(jie)線(xian)應盡量短,足夠粗,并應接(jie)(jie)觸良好、可靠,以減(jian)少因(yin)接(jie)(jie)線(xian)的(de)電阻和分布(bu)參數所帶(dai)來的(de)測量誤(wu)差(cha)。
5.被(bei)測件不要直(zhi)接擱(ge)在面(mian)板頂部,離頂部一公分以上(shang),必要時可用(yong)低損耗的(de)(de)絕緣材料如聚苯乙烯等做成的(de)(de)襯(chen)墊(dian)物襯(chen)墊(dian)。
6.手不得靠(kao)近試件,以免人(ren)體感應(ying)影(ying)響造成測量誤差,有屏蔽的試件,屏蔽罩應(ying)連(lian)接(jie)(jie)在(zai)低(di)電位(wei)端(duan)的接(jie)(jie)線(xian)柱(zhu)。
- 上一個: GDAT-A橡膠片介電常數介質損耗測試儀
- 下一個(ge): HMLQ-500工業海綿落球回彈試驗機