絕緣材料體積、表面電阻率測(cè)定儀廠家  工作原理

根據(jù)歐姆定律，被測(cè)電阻R等于施加電壓V除以通過的電流I。即

   V

R= ---

   I

傳統(tǒng)的儀器的工作原理是測(cè)量電壓V固定，通過測(cè)量流過被測(cè)物體的電流I以標(biāo)定電阻的刻度來讀出電阻值。從上式可以看出，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(cè)量不同的電阻時(shí)，其電壓V也會(huì)有些變化，所以普通的高阻計(jì)的精度是很難提高的。

BEST-121體積、表面電阻率測(cè)定儀是同時(shí)測(cè)出電阻兩端的電壓V和流過電阻的電流I，通過內(nèi)部的大規(guī)模集成電路完成電壓除以電流的計(jì)算，然后把所得到的結(jié)果經(jīng)過A/D轉(zhuǎn)換后以數(shù)字顯示出電阻值，即便是電阻兩端的電壓V和流過電阻的電流I是同時(shí)變化，其顯示的電阻值不象普通高阻計(jì)那樣因被測(cè)電壓V的變化或電流Ｉ的變化而變，所以, 即使測(cè)量電壓、被測(cè)量電阻、電源電壓等發(fā)生變化對(duì)其結(jié)果影響不大，其測(cè)量精度很高。從理論上講其誤差可以做到零。而實(shí)際誤差可以做到千分之幾或萬(wàn)分之幾。

絕緣材料體積、表面電阻率測(cè)定儀廠家  技術(shù)指標(biāo)

1. 電阻測(cè)量范圍： 1?104Ω～1?1018Ω，分為十個(gè)量程。

2. 電流測(cè)量范圍為2?10-4A ～1?10-16A

3. 全數(shù)字液晶屏顯示。

4. 準(zhǔn)確度: 準(zhǔn)確度優(yōu)于下表:

( 超出有效顯示范圍時(shí)誤差有可能增加)測(cè)試電流準(zhǔn)確度與電阻相同測(cè)試電壓準(zhǔn)確度為10%

5. 使用環(huán)境: 溫度 -10℃～50℃ 相對(duì)濕度<90%。

6. 測(cè)試電壓: DC10V、50V、100V、250V、500V、1000V。?10%

7. 供電形式: AC 220V，50HZ，功耗約10W。

8. 儀器尺寸: 300ｍｍ? 280ｍｍ? 150 mm。

9. 質(zhì)量: 約3.0KG。

典型應(yīng)用

1 測(cè)量防靜電鞋、導(dǎo)電鞋的電阻值

按照國(guó)家標(biāo)準(zhǔn)GB4386-84《防靜電膠底鞋（靴）、導(dǎo)電膠底鞋（靴）電阻值測(cè)量方法》防靜電鞋的電阻值必須為0.5.?105Ω1.0?108Ω范圍內(nèi)，導(dǎo)電鞋的電阻值必須不大于1.5X105歐姆.不僅制造廠在出廠時(shí)必須按這一標(biāo)準(zhǔn)檢驗(yàn)，合格后才能出廠，在工廠使用過程中也必須按這一標(biāo)準(zhǔn)進(jìn)行定期檢驗(yàn)，合格后才能穿用。

制造廠測(cè)量新鞋的電阻值時(shí)，應(yīng)將硫化后有新鞋放置24小時(shí)以上，然后在測(cè)量所要求的溫度、濕度環(huán)境中放置2小時(shí)以后才能進(jìn)行測(cè)量。使用單位在定期檢測(cè)時(shí)應(yīng)將鞋洗干凈，其溫濕度的要求及放置時(shí)間同上。測(cè)量環(huán)境要求為：溫度：10℃ ～ 40℃相對(duì)濕度為40% ～ 70%。 由于HEST121型數(shù)字表面、體積電阻率測(cè)定儀是內(nèi)部同時(shí)測(cè)量電壓和電流，且直接顯示出電阻值，所以不必另外使用電壓表和電流表以及計(jì)算電阻值。

通常測(cè)試防靜電鞋只用106、107、108Ω檔，測(cè)試完畢將開關(guān)撥回104檔。

根據(jù)上述測(cè)試的結(jié)果，根據(jù)標(biāo)準(zhǔn)來確定被測(cè)鞋是否合格或能否穿用。

2. 測(cè)量防靜電材料的電阻及電阻率

一般防靜電材料的電阻值在105 Ω～1010 Ω左右的范圍內(nèi)，其測(cè)量電極可采用三電極或二電極，其具體測(cè)量方法可參照有關(guān)的標(biāo)準(zhǔn)或有關(guān)資料。

3. 測(cè)量計(jì)算機(jī)房用活動(dòng)地板的系統(tǒng)電阻值

按照國(guó)家標(biāo)準(zhǔn)ＧＢ6650-86《計(jì)算機(jī)房用活動(dòng)地板技術(shù)條件》。采用該標(biāo)準(zhǔn)的電極（也可用三電極中的主電極）測(cè)量。

4. 測(cè)量絕緣材料電阻(率)

絕緣材料如塑料（聚乙稀，聚氯乙稀，尼龍等）橡膠等的電阻率很高，測(cè)量時(shí)應(yīng)采取屏蔽措施，以免讀數(shù)不穩(wěn)甚至無法測(cè)量。測(cè)量時(shí)可采用三電極。具體方法可參照國(guó)家標(biāo)準(zhǔn)GB1410。

5. 測(cè)量電流及1014Ω以上超高電阻的測(cè)量

當(dāng)測(cè)量超過1014Ω以上的超高電阻時(shí),可以通過測(cè)量電流的方法,然后用歐姆

定律求出超高電阻值。測(cè)量電流與測(cè)量電阻的方法基本相同，

例如：電流表頭顯示讀數(shù)為1.234，量程位置處在10－8，則電流為I=1.234?10-8 A

利用歐姆定律

V

R= ---

I

可以計(jì)算出電阻值。利用測(cè)量電流的方法可測(cè)量超過1014Ω以上的超高電阻1015～1018Ω。 

主要標(biāo)準(zhǔn)：

GB/T 1410-2006 《 固體絕緣材料體積電阻率和表面電阻率試驗(yàn)方法》

ASTM D257-99  《絕緣材料的直流電阻或電導(dǎo)試驗(yàn)方法》

GB/T 2439-2001《硫化橡膠或熱塑性橡膠 導(dǎo)電性能和耗散性能電阻率的測(cè)定》

GB/T 10581-2006 《絕緣材料在高溫下電阻和電阻率的試驗(yàn)方法》

GB/T 1692-2008 《硫化橡膠絕緣電阻率的測(cè)定》

GB/T 12703.4-2010 《紡織品 靜電性能的評(píng)定 第４部分：電阻率》

GB/T 10064-2006《測(cè)定固體絕緣材料絕緣電阻的試驗(yàn)方法》

標(biāo)準(zhǔn)配置：

1,測(cè)試儀器：1臺(tái)

2,電源線：1條

3,測(cè)量線：3根（屏蔽線,測(cè)試接線,接地線）

4,使用說明書：1份

working principle

According to Ohm's Law, the measured resistance R is equal to the applied voltage V divided by the current I passing through. That is

V

R= ---

I

The working principle of traditional instruments is to measure a fixed voltage V and read the resistance value by measuring the current I flowing through the measured object to calibrate the resistance scale. From the above equation, it can be seen that since the current I is inversely proportional to the resistance, rather than directly proportional, the displayed value of the resistance is nonlinear. That is, when the resistance is infinite, the current is zero, and the zero position of the meter head is ∞. The scales near it are very dense, and the resolution is very low. The entire scale is non-linear. Moreover, due to the variation in voltage V when measuring different resistances, it is difficult to improve the accuracy of ordinary high resistance meters.

The BEST-121 volume and surface resistivity measuring instrument simultaneously measures the voltage V across the resistor and the current I flowing through the resistor. The voltage divided by the current is calculated through an internal large-scale integrated circuit, and the obtained result is then converted into a digital display of the resistance value through A/D conversion. Even if the voltage V across the resistor and the current I flowing through the resistor change simultaneously, the displayed resistance value does not change due to changes in the measured voltage V or current I like ordinary high resistance meters. Therefore, even if there are changes in the measured voltage, measured resistance, power supply voltage, etc., the measurement accuracy is very high. In theory, its error can be reduced to zero. And the actual error can reach a few thousandths or tens of thousands.

Technical indicators

1. Resistance measurement range: 1 ? 104 Ω~1 ? 1018 Ω, divided into ten measuring ranges.

2. The current measurement range is 2 ? 10-4A to 1 ? 10-16A

3. Full digital LCD screen display.

4. Accuracy: The accuracy is better than the following table:

Effective display range of range: 20-30 ℃ RH<80%

104 0.01~19.99 1%

105 0.01～19.99 1%

106 0.01～19.99 1%

107 0.01～19.99 1%

108 0.01～19.99 1%

109 0.01～19.99 1%

1010 0.01~19.99 5% 2 words

1011 0.01~19.99 5% 2 words

1012 0.01~19.99 5% 5 words

1013 0.01~19.99 10% 5 words

1014 0.01~19.99 10% 5 words

Above 1014, 0.01~19.99, 10-15% 5 words

The accuracy of the test current is the same as that of the resistance, and the accuracy of the test voltage is 10%

5. Operating environment: Temperature -10 ℃~50 ℃, relative humidity<90%.

6. Test voltage: DC10V、50V、100V、250V、500V、1000V。 ?10%

7. Power supply form: AC 220V，50HZ， The power consumption is about 10W.

8. Instrument size: 300mm ? 280mm ? 150mm.

9. Quality: Approximately 3.0KG.

Typical applications

Measure the resistance value of anti-static shoes and conductive shoes

According to the national standard GB4386-84 "Measurement method for resistance value of anti-static rubber soled shoes (boots) and conductive rubber soled shoes (boots)", the resistance value of anti-static shoes must be within the range of 0.5. ? 105 Ω 1.0 ? 108 Ω, and the resistance value of conductive shoes must not exceed 1.5X105 Ω Not only must the manufacturing plant be inspected according to this standard before leaving the factory, but it must also be regularly inspected according to this standard during use in the factory, and only after passing the inspection can it be worn.

When measuring the resistance value of new shoes in the manufacturing plant, the vulcanized new shoes should be left for more than 24 hours, and then placed in the required temperature and humidity environment for 2 hours before measurement can be carried out. The user unit should wash the shoes clean during regular inspections, with the same temperature and humidity requirements and storage time as above. The measurement environment requirements are: temperature: 10 ℃~40 ℃, relative humidity: 40%~70%. Due to the HEST121 digital surface and volume resistivity meter measuring both voltage and current internally and displaying resistance values directly, there is no need to use separate voltmeters and ammeters to calculate resistance values.

Usually, anti-static shoes are tested using only 106, 107, and 108 Ω settings. After testing, turn the switch back to 104.

Based on the results of the above tests, determine whether the tested shoes are qualified or can be worn according to the standards.

2. Measure the resistance and resistivity of anti-static materials

The resistance value of general anti-static materials is in the range of around 105 Ω to 1010 Ω, and their measuring electrodes can use three or two electrodes. The specific measurement method can refer to relevant standards or data.

3. Measure the system resistance value of the raised floor used in the computer room

According to the national standard GB6650-86 "Technical Conditions for Raised Floor in Computer Room". Measure using the electrode of this standard (or the main electrode among the three electrodes).

4. Measure the resistance (rate) of insulation materials

Insulating materials such as plastics (polyethylene, polyvinyl chloride, nylon, etc.) and rubber have high electrical resistivity, and shielding measures should be taken during measurement to avoid unstable readings or even inability to measure. Three electrodes can be used for measurement. The specific method can refer to the national standard GB1410.

5. Measurement of current and ultra-high resistance above 1014 Ω

When measuring ultra-high resistance exceeding 1014 Ω, the method of measuring current can be used, and then ohms can be used

The law determines the ultra-high resistance value. The methods for measuring current and measuring resistance are basically the same,

For example, if the ammeter displays a reading of 1.234 and the range is between 10-8, then the current is I=1.234 ? 10-8 A

Using Ohm's Law

V

R= ---

I

The resistance value can be calculated. The method of measuring current can be used to measure ultra-high resistance of 1015-1018 Ω exceeding 1014 Ω.

Main standards:

GB/T 1410-2006 "Test Method for Volume and Surface resistivity of Solid Insulation Materials"

ASTM D257-99 "Test Method for DC Resistance or Conductivity of Insulation Materials"

GB/T 2439-2001 "Determination of Electrical Conductivity and Dissipation Properties of Vulcanized Rubber or Thermoplastic Rubber"

GB/T 10581-2006 "Test method for resistance and resistivity of insulating materials at high temperatures"

GB/T 1692-2008 "Determination of Insulation Resistance of Vulcanized Rubber"

GB/T 12703.4-2010 "Evaluation of electrostatic properties of textiles - Part 4: Electrical resistivity"

GB/T 10064-2006 "Test Method for Determining Insulation Resistance of Solid Insulation Materials"

Standard configuration:

1. Testing instrument: 1 unit

2. Power cord: 1

3. Measurement wires: 3 wires (shielded wire, test wire, grounding wire)

4. User manual: 1 copy

溫度影響

溫度對(duì)不同物質(zhì)的電阻值均有不同的影晌。

導(dǎo)電體在接近室溫的溫度，良導(dǎo)體的電阻值，通常與溫度成線性關(guān)系：

ρ=ρ0(1 αt)

上式中的a 稱為電阻的溫度系數(shù)。

未經(jīng)摻雜的半導(dǎo)體的電阻隨溫度升高而下降：

有摻雜的半導(dǎo)體變化較為復(fù)雜。當(dāng)溫度從絕對(duì)零度上升，半導(dǎo)體的電阻先是減少，到了絕大部分的帶電粒子（電子或電洞/空穴） 離開了它們的載體后，電阻會(huì)因帶電粒子的活動(dòng)力下降而隨溫度稍為上升。當(dāng)溫度升得更高，半導(dǎo)體會(huì)產(chǎn)生新的載體 （和未經(jīng)摻雜的半導(dǎo)體一樣） ，原有的載體 （因滲雜而產(chǎn)生者） 重要性下降，于是電阻會(huì)再度下降。

絕緣體和電解質(zhì)絕緣體和電解質(zhì)的電阻與溫度的關(guān)系一般不成比例，而且不同物質(zhì)有不同的變化，故不在此列出概括性的算式。

電源

要求有很穩(wěn)定的直流電壓源。這可用蓄電油或一個(gè)整流穩(wěn)壓的電摞來提供。對(duì)電源的穩(wěn)定度要求是由電壓變化導(dǎo)致的電流變化與被測(cè)電流相比可忽略不計(jì)。

加到整個(gè)試樣上的試驗(yàn)電壓通常規(guī)定為100V、250V、500V、1000 V、2500 V、5000 V, 10000 V 和15000 V。 常用的電壓是100V、500V和1000 V。

在某些情況下，試樣的電阻與施加電壓的極性有關(guān)

如果電阻是與極性有關(guān)的，則宜加以注明。取兩次電阻值的幾何平均值（對(duì)數(shù)算術(shù)平均值的反對(duì)數(shù)）作為結(jié)果。

由于試樣電阻可能與電壓有依存關(guān)系，因此應(yīng)在報(bào)告中注明試驗(yàn)電壓值。

報(bào)告

報(bào)告應(yīng)至少包括下述情況：

a) 電阻率測(cè)試儀（電阻率測(cè)定儀）關(guān)于材料的說明和標(biāo)志（名稱、等級(jí)、顏色、制造商等）；

b) 電阻率測(cè)試儀（電阻率測(cè)定儀）試樣的形狀和尺寸；

c) 電阻率測(cè)試儀（電阻率測(cè)定儀）電極和保護(hù)裝置的形式、材料和尺寸；

d) 電阻率測(cè)試儀（電阻率測(cè)定儀）試樣的處理（清潔、預(yù)干燥、處理時(shí)間、濕度和溫度）等；

e) 電阻率測(cè)試儀（電阻率測(cè)定儀）試驗(yàn)條件（試樣溫度、相對(duì)由度）；

f) 電阻率測(cè)試儀（電阻率測(cè)定儀）測(cè)量方法；

g) 電阻率測(cè)試儀（電阻率測(cè)定儀）施加電壓；

h) 電阻率測(cè)試儀（電阻率測(cè)定儀）體和、電阻率（需要時(shí)）；

注1：當(dāng)規(guī)定了一個(gè)固定的電化時(shí)間時(shí)，注明此時(shí)間，給出個(gè)別值，并報(bào)告中值作為體積電阻率。

注2 ： 當(dāng)在不同的電化時(shí)間后測(cè)試時(shí)，應(yīng)按如下要求報(bào)告：

當(dāng)在相同的電化時(shí)間里試樣達(dá)到一個(gè)穩(wěn)定狀態(tài)肘，給出個(gè)別值，并報(bào)告中值作為體積電阻率。在這個(gè)電化時(shí)間里有某些試樣不能達(dá)到穩(wěn)定狀態(tài)，則報(bào)告不能達(dá)到穩(wěn)定狀態(tài)的試樣數(shù)，并分別地給出它們的結(jié)果。當(dāng)測(cè)試結(jié)果取決于電化時(shí)間時(shí)，則報(bào)告它們之間的關(guān)系，例如．以圖的形式或給出在電化Imin、10min和100min后的體積電阻率的中值。

i) 表面電阻率（需要時(shí)）：

給出電化時(shí)間為1 min的個(gè)別值，并報(bào)告其中值作為表面電阻率。