【正文】 nomenon, indicating activities, contacts are being exposed failures. 5 正溫度系數(shù)熱敏電阻 (PTC) 的檢測(cè)5. positive temperature coefficient thermistor (PTC) detection. 檢測(cè)時(shí)，用萬用表 R1 擋，具體可分兩步操作： A 常溫檢測(cè) ( 室內(nèi)溫度接近 25 ℃ ) ；將兩表筆接觸 PTC 熱敏電阻的兩引腳測(cè)出其實(shí)際阻值，并與標(biāo)稱阻值相對(duì)比，二者相差在177。 2 Ω內(nèi)即為正常。 Detection with a multimeter R 1 block, concrete can be a twostep operation:temperature detection (indoor temperature close to 25 ℃)。 the two tables sum of the two contact pins PTC thermistor measured the actual resistance, and with the pared to the nominal resistance, both of difference shall be within 177。 2 Ω in the normal. 實(shí)際阻值若與標(biāo)稱阻值相差過大，則說明其性能不良或已損壞。 Resistance if it is the actual difference between the nominal resistance value is too large, its performance is illustrated in bad or damaged. B 加溫檢測(cè)；在常溫測(cè)試正常的基礎(chǔ)上，即可進(jìn)行第二步測(cè)試 加溫檢測(cè)，將一熱源 ( 例如電烙鐵 ) 靠近 PTC 熱敏電阻對(duì)其加熱，同時(shí)用萬用表監(jiān)測(cè)其電阻值是否隨溫度的升高而增大，如是，說明熱敏電阻正常，若阻值無變化，說明其性能變劣，不能繼續(xù)使用。heat detection。 at room temperature, on the basis of the tests are normal, you can carry out the second step tests heat detection, will be a heat source (for example, iron) near the PTC thermistor to its heating, while monitoring its resistance with the multimeter whether it increases with increasing temperature which, in the case shows that the thermistor to normal, if no change in resistance, indicating inferior performance changes are not in use. 注意不要使熱源與 PTC 熱敏電阻靠得過近或直接接觸熱敏電阻，以防止將其燙壞。 Be careful not to make the heat source and the PTC thermistor by too close or direct contact thermal resistance, in order to prevent their Tanghuai. 6 負(fù)溫度系數(shù)熱敏電阻 (NTC) 的檢測(cè)6. negative temperature coefficient thermistor (NTC) detection. (1) 、測(cè)量標(biāo)稱電阻值 R(1), measured nominal resistance value Rt 用萬用表測(cè)量 NTC 熱敏電阻的方法與測(cè)量普通固定電阻的方法相同，即根據(jù) NTC 熱敏電阻的標(biāo)稱阻值選擇合適的電阻擋可直接測(cè)出 Rt 的實(shí)際值。NTC thermistor with the multimeter measuring methods and measured the same way as ordinary fixed resistor that, according to the nominal resistance of NTC thermistor select the appropriate power block can be directly measured the actual value of Rt. 但因 NTC 熱敏電阻對(duì)溫度很敏感，故測(cè)試時(shí)應(yīng)注意以下幾點(diǎn)： A  Rt 是生產(chǎn)廠家在環(huán)境溫度為 25 ℃時(shí)所測(cè)得的，所以用萬用表測(cè)量 Rt 時(shí)，亦應(yīng)在環(huán)境溫度接近 25 ℃時(shí)進(jìn)行，以保證測(cè)試的可信度。 But NTC thermistor is sensitive to temperature, so testing should note the following: Rt is a manufacturer of environmental temperature measured at 25 ℃, so the measure with the multimeter Rt should also be at ambient temperature when close to 25 ℃ in order to ensure the credibility test. B 測(cè)量功率不得超過規(guī)定值，以免電流熱效應(yīng)引起測(cè)量誤差。 measuring power shall not exceed the specified value in order to avoid current heating effect caused by measurement error. C 注意正確操作。 attention to proper operation. 測(cè)試時(shí)，不要用手捏住熱敏電阻體，以防止人體溫度對(duì)測(cè)試產(chǎn)生影響。 Test, do not pinch fingers thermistor body, in order to prevent the body temperature of the test impact. (2) 、估測(cè)溫度系數(shù)α t(2), estimate the temperature coefficient αt 先在室溫 t1 下測(cè)得電阻值 Rt1 ，再用電烙鐵作熱源，靠近熱敏電阻 Rt ，測(cè)出電阻值 RT2 ，同時(shí)用溫度計(jì)測(cè)出此時(shí)熱敏電阻 RT 表面的平均溫度 t2 再進(jìn)行計(jì)算。First measured at room temperature under t1 resistance Rt1, electric iron to heat and then, near the thermistor Rt, measure the resistance RT2, the same time, measured with the thermometer at this time the surface of the thermistor RT and then calculated the average temperature t2. 7  testing. 用萬用表的 R1k 擋測(cè)量壓敏電阻兩引腳之間的正、反向絕緣電阻，均為無窮大，否則，說明漏電流大。With the multimeter measuring R 1k block varistors are between the two pins, reverse insulation resistance, are infinite, otherwise, indicating leakage current. 若所測(cè)電阻很小，說明壓敏電阻已損壞，不能使用。If the measured resistance is very small, shows varistors have been damaged and can not be used. 8 光敏電阻的檢測(cè)。8. photosensitive resistance 用一黑紙片將光敏電阻的透光窗口遮住，此時(shí)萬用表的指針基本保持不動(dòng)，阻值接近無 black pieces of paper with a translucent window, the photosensitive resistor cover, this time multimeter pointer remained motionless close to infinite resistance. 此值越大說明光敏電阻性能越好。 This value shows the bigger the better performance of lightsensitive resistors. 若此值很小或接近為零，說明光敏電阻已燒穿損壞，不能再繼續(xù)使用。 If this value is very small or close to zero, indicating photosensitive resistor has burn damage, can no longer continue to be used. B 將一光源對(duì)準(zhǔn)光敏電阻的透光窗口，此時(shí)萬用表的指針應(yīng)有較大幅度的擺動(dòng)，阻值明顯減小。 will be a light source aligned photosensitive resistance translucent window, this time multimeter pointer should be more substantial swing, resistance significantly reduced. 此值越小說明光敏電阻性能越好。 The smaller this value shows the better performance of lightsensitive resistors. 若此值很大甚至無窮大，表明光敏電阻內(nèi)部開路損壞，也不能再繼續(xù)使用。 If this value is great or even infinite, indicating that the internal resistance of open photosensitive damage, can no longer continue to 將光敏電阻透光窗口對(duì)準(zhǔn)入射光線，用小黑紙片在光敏電阻的遮光窗上部晃動(dòng)，使其間斷受光，此時(shí)萬用表指針應(yīng)隨黑紙片的晃動(dòng)而the photosensitive resistance translucent window aligned incident light line, with the black pieces of paper in the upper window shading photosensitive resistor shaking to break by the light, this time with the black pieces of paper multimeter pointer should be about the rock and swing. 如果萬用表指針始終停在某一位置不隨紙片晃動(dòng)而擺動(dòng)，說明光敏電阻的光敏材料已經(jīng)損壞。 If the meter pointer is always parked in a certain location does not rock and sway with the pieces of paper, indicating the photosensitive photosensitive resistance materials have been damaged. 二、電容器的檢測(cè)方法與經(jīng)驗(yàn)Ⅱ. capacitors detection methods and experience 1  of the fixed capacitor A 檢測(cè) 10pF 以下的小電容Detect the small capacitance below ,因 10pF 以下的固定電容器容量太小，用萬用表進(jìn)行測(cè)量，只能定性的檢查其是否有漏電，內(nèi)部短路或擊穿現(xiàn)象。10pF capacitors due to the following fixedsize too small to measure with the multimeter, only a qualitative check whether there is leakage, the internal short circuit or breakdown phenomenon. 測(cè)量時(shí)，可選用萬用表 R10k 擋，用兩表筆分別任意接電容的兩個(gè)引腳，阻值應(yīng)為無窮大。 Measurements, it can use multimeter R 10k block, using two tables T 2 respectively, the capacitance of arbitrary access pin, resistance should be infinite. 若測(cè)出阻值 ( 指針向右擺動(dòng) ) 為零，則說明電容漏電損壞或內(nèi)部擊穿。 If the measured resistance (pointer to the right swing) is zero, then c