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體積電阻率表面電阻率測試儀  型號：BEST-121

一、根據(jù)歐姆定律，被測電阻Rx等于施加電壓V除以通過的電流I。傳統(tǒng)的高阻計(jì)的工作原理是測量電壓V固定，通過測量流過取樣電阻的電流I來得到電阻值。從歐姆定律可以看出，由于電流I是與電阻成反比，而不是成正比，所以電阻的顯示值是非線性的，即電阻無窮大時(shí)，電流為零，即表頭的零位處是∞，其附近的刻度非常密，分辨率很低。整個(gè)刻度是非線性的。又由于測量不同的電阻時(shí)，其電壓V也會有些變化，所以普通的高阻計(jì)是精度差、分辨率低。

四、測試 

將被測試樣用測量電纜線和導(dǎo)線分別與訊號輸入端和測試電壓輸出端連接。 將測試電壓選擇開關(guān)置于所需要的測試電壓檔。 將“放電-測試”開關(guān)置于“測試”檔，輸入短路開關(guān)仍置于“短路”。對試樣經(jīng)一定時(shí)間的充電以后（視試樣的容量大小而定，一般為15秒。電容量大時(shí)，可適當(dāng)延長充電時(shí)間），即可將輸入短路開關(guān)撳至“測量”進(jìn)行讀數(shù)，若發(fā)現(xiàn)指針很快打出滿刻度，應(yīng)立即撳輸入短路開關(guān)，使其置于“短路”， 將“放電-測試”開關(guān)置于“放電”檔，等查明原因并排除故障后再進(jìn)行測試。 當(dāng)輸入短路開關(guān)置于測量后，如發(fā)現(xiàn)表頭無讀數(shù)，或指示很少，可將倍率開關(guān)逐步升高，數(shù)字顯示依次為7、8、9、…直至讀數(shù)清晰為止（盡量取儀表上1～10的那段刻度）。通過旋轉(zhuǎn)倍率旋鈕，使示數(shù)處于半偏以內(nèi)的位置，便于讀數(shù)。測量時(shí)先將RV/RS轉(zhuǎn)換開關(guān)置于RV測量體積電阻，然后置于RS測量表面電阻。讀數(shù)方法如下：表頭指示為讀數(shù)，數(shù)字顯示為10的指數(shù)，單位W。用不同電壓進(jìn)行測量時(shí)，其電阻系數(shù)不一樣，電阻系數(shù)標(biāo)在電壓值下方。將儀表上的讀數(shù)（單位為兆歐）乘以倍率開關(guān)所指示的倍率及測試電壓開關(guān)所指的系數(shù)（10V為0.01；100V為0.1；250V為0.25；500V為0.5；1000V為1）即為被測試樣的絕緣電阻值。例如：讀數(shù)為3.5′106W倍率開關(guān)所指系數(shù)為108，測量電壓為100V，則被測電阻值為：3.5′106′108′0.1 =3.5′1013W。 在測試絕緣電阻時(shí)，如發(fā)現(xiàn)指針有不斷上升的現(xiàn)象，這是由于電介質(zhì)的吸收現(xiàn)象所致，若在很長時(shí)間內(nèi)未能穩(wěn)定，則一般情況下取接通測試開關(guān)后一分鐘時(shí)的讀數(shù)作為試樣的絕緣電阻值。

一個(gè)試樣測試完畢，即將輸入短路撳鍵置于“短路”，測試電壓控制開關(guān)置于“關(guān)”后，將方式選擇開關(guān)撥向放電位置，幾分鐘后方可取出試樣。對電容量較大的試樣者需經(jīng)1分鐘左右的放電，方能取出試樣，以免受測試系統(tǒng)電容中殘余電荷的電擊。。若要重復(fù)測試時(shí)，應(yīng)將試樣上的殘留電荷全部放掉方能進(jìn)行。

然后進(jìn)入下一個(gè)試樣的測試：為了操作簡便無誤，測量絕緣材料體積電阻（Rv）和表面電阻（Rs）時(shí)采用了轉(zhuǎn)換開關(guān)。當(dāng)旋鈕指在Rv處時(shí)，高壓電極加上測試電壓。保護(hù)電極接地，當(dāng)旋鈕指在Rs處時(shí)，保護(hù)電極加上測試電壓，高壓電極接地。 儀器使用完畢，應(yīng)先切斷電源，將面板上各開關(guān)恢復(fù)到測試前的位置，拆除所有接線，將儀器安放保管好。

準(zhǔn)備 

使用前，面板上的各開關(guān)位置應(yīng)如下：

ａ） 倍率開關(guān)置于靈敏度zui低檔位置。

ｂ） 測試電壓開關(guān)置于“10V”處

c） “放電-測試”開關(guān)置于“放電”位置。

d） 電源總開關(guān)（POWER）置于“關(guān)”。

e） 輸入短路撳鍵置于“短路”。

f） 極性開關(guān)置于“0”。

檢查測試環(huán)境的濕度是否在允許的范圍內(nèi)。尤其當(dāng)環(huán)境濕度高于80%以上時(shí)，對測量較高的絕緣電阻（大于10 11Ω及小于10-8 A）時(shí)微電流可能會導(dǎo)致較大的誤差。

接通電源預(yù)熱30分鐘，將極性開關(guān)置于“+”，此時(shí)可能發(fā)現(xiàn)指示儀表的指針會離開“∞”及“0”處，這時(shí)可慢慢調(diào)節(jié)“∞”及“0”電位器，使指針置于“∞”及“0”處。

五、儀器特征

本儀器測量采用三電極法對試樣進(jìn)行測試，其試驗(yàn)裝置主要有平板式電極裝置和高阻計(jì)兩部分組成。基本原理是對試樣加入不同擋位的直流電壓，流經(jīng)試樣的微弱電流用標(biāo)準(zhǔn)電阻取樣放大后，從高阻計(jì)上讀出。數(shù)字直接顯示出電阻值,精度高、顯示迅速、穩(wěn)定性好、讀數(shù)方便。技術(shù)指標(biāo)1、采用高集成度的3 1/2位數(shù)字顯示。2、量程范圍：1×105Ω ～1.999×1014 Ω

3、測試電壓為DC100V或DC500V或用戶訂制

4、工作環(huán)境溫度：20℃±2℃，濕度：35%±10%RH

5、儀器在穩(wěn)定的工作電壓及無信號輸入時(shí)1--8小時(shí)之間零點(diǎn)漂移小于±5%

6、儀器對標(biāo)準(zhǔn)電阻測量的基本誤差：≤±10% 

六、 技術(shù)參數(shù) 

·         型 號 SB36固體（液體）體積電阻率及表面電阻率測試儀

·         額定電壓 10 100 250 500 1000 準(zhǔn)確度 ±5 % 

·         電阻測量 1* 106～1* 1017準(zhǔn)確度 ±10 % ±20 % 

 ·         微電流測量 1* 105～1* 1014準(zhǔn)確度 ±10 % ±20 % 

·         外形尺寸/重量（MM /KG） 380W * 260D * 150H / 10 主要用途及特點(diǎn): 

·         適用于科研、工廠、學(xué)校、企業(yè)部門對絕緣材料、電工產(chǎn)品、電子設(shè)備以及元件的絕緣測量和高阻值兆歐電阻的測量也可用著微電流測量，是一種直讀式和微電流兩用儀器。 

測試電壓（V） 誤 差 

DC—10V ±5% 

DC—50V ±5% 

DC—100V ±5% 

DC—500V ±5% 

DC—1000V ±5% 

Volume resistivity of surface resistivity tester

Digital high resistance, a current measuring instrument type: EST-121: volume resistivity, surface resistivity uses: Instrumentation Test

One, volume resistivity surface resistivity tester overview

This instrument can measure high resistance, and measuring current. The American company In large scale integrated circuit and patented technology, the instrument has the advantages of small volume, light weight, high accuracy. Dual 3.1/2 digital display the resistance high resistance meter and current. Limit from 1× 104 Ω～ 1× 1018 Ω, is currently the most wide measurement range, the most accurate digital ultra high resistance meter. Current measurement range of 2× 10-4 ～ 1× 10-16A. The built-in test voltage is 10/50/100/250/500/1000V adjustable. The instrument has the advantages of high precision, good stability, showing a rapid, easy reading, applied to anti-static products such as anti-static shoes, anti-static plastic rubber products, computer room anti-static floor activities such as the resistance value of the test as well as insulating materials electrical and electronic products insulation resistance measurement. The instrument can measure the resistance, and can directly measure the weak current. 

Instrument is fully consistent with and better than the national standard GB1410 " solid electrical insulating materials, insulation resistance, volume resistivity and surface resistance test method " and " American Standard ASTM D257 DC resistance or conductance of insulating materials test methods " and other standards.

Two, volume resistivity surface resistivity tester main features

Resistance measuring range 0.01× 104 Ω～ 1× 1018 Ω

Current measurement range of 2× 10-4A ～ 1× 10-16A

Small volume, light weight, high accuracy

Resistance, current double display

Good performance is stable, easy reading

All the test voltage （ 10/50/100/250/500/1000V ） test resistance results in reading, is removed from the old high resistance meter in different test voltage or different scale should be multiplied by the coefficient of the inconvenient trouble, allowing the measurement of high resistance as the multimeter is used to measure the general resistance of samples is simple.

Not only can measure high resistance and micro current

Wide application: applied to anti-static products such as anti-static shoes, anti-static plastic rubber products, computer room anti-static floor activities such as resistance testing electrical and electronic products insulation resistance measurement

Three, volume resistivity surface resistivity tester technical indicators

The 1 resistor measurement range: 0.01× 104 Ω～ 1× 1018 Ω.

The 2 current measurement range : 2 × 10-4A～ 1 × 10-16A

3 double header display: 3.1/2 LED display

4 built-in test voltage: 10V, 50V, 100V, 250, 500, 1000V

5 basic accuracy: 1% （ note ）

6: use environment temperature: 0℃ ~ 40 ℃, relative humidity <80%

7 built-in test voltage: 10/50/100/250/500/1000V arbitrary switching

The 8 power supply forms: AC 220V, 50HZ, power consumption is about 5W

Four, volume resistivity surface resistivity meter working principle

According to the Ohm's law, the measured resistance is equal to voltage is applied through Rx V divided by the current I. The traditional high resistance meter is the working principle of measuring voltage V fixed, by measuring the current flows through the sampling resistor I to get the value of resistance. From Ohm's law can be seen, because the current I is inversely proportional to the resistance, but not proportional to the resistance, so the display value is nonlinear, namely the resistance to infinity, the current is zero, i.e., zero is∞, in the vicinity of the scale is very dense, with a low resolution. The scale is nonlinear. Because the measurement of different resistance, the voltage V also vary, so the average high resistance meter is poor accuracy, low resolution.

At the same time measure the voltage across the resistor V and the current through the resistor I, through the interior of the large scale integrated circuit to complete the voltage divided by the current calculation, and then the results obtained after A/D conversion to digital show resistance, even if the voltage across the resistor V and the current through the resistor I is changed at the same time, the display resistance value is not as common due to high resistance meter that measured voltage or current change of V I change, so, even if the measured voltage, resistance, power supply voltage is measured the changes in the results have little effect, the measurement accuracy is very high （ patent ）, theoretically the error can be zero, while the actual error can be done a few thousandths or extremely few.

Typical application

1 measurements of anti-static shoes, conductive shoes resistance value

2, measurement of the antistatic material resistance and resistivity

3, measurement computer room with movable floor system resistance

4, measurement of insulation resistance （ rate）

5, photodiode dark current measurement

6, physics, optics and materials research

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EST-121 volume surface resistivity measuring instrument

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