【正文】 元器件的檢測經(jīng)驗(yàn)和方法進(jìn)行介紹供對(duì)考。 10 ％或177。 color ring while resistance is able to mark to determine the color wheel, but is best when used with a multimeter to test the actual resistance. 2 水泥電阻的檢2 .cement resistance testing. 檢測水泥電阻的方法及注意事項(xiàng)與檢測普通固定電阻完全相同。 detect the activities of potentiometer arm and the contact resistance is a good film. 用萬用表的歐姆檔測 1 、 2( 或 2 、 3) 兩端，將電位器的轉(zhuǎn)軸按逆時(shí)針方向旋至接近 關(guān) 的位置，這時(shí)電阻值越小越好。 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。 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。 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。 Multimeter selected R 1k block. 兩只三極管的β值均為 100 以上，且穿透電流要小。 Based on experience, under normal circumstances, 1 ~ 47 μ F between the capacitance, R 1k block can be measured, greater than 47 μ F capacitor can be used R 100 block measurement. B 將萬用表紅表筆接負(fù)極，黑表筆接正極，在剛接觸的瞬間，萬用表指針即向右偏轉(zhuǎn)較大偏度 ( 對(duì)于同一電阻擋，容量越大，擺幅越大 ) ，接著逐漸向左回轉(zhuǎn)，直到停在某一位置。 Two measurements of resistance and that one is a big positive then the law, that the black pen then the table is positive, the red pen then the table is the negative. D 使用萬用表電阻擋，采用給電解電容進(jìn)行正、反向充電的方法，根據(jù)指針向右擺動(dòng)幅度的大小，可估測出電解電容的容量。 Placed in the multimeter R 1 block, red and black colorcoded table pen the next inductor leads to either a client, this time the pointer should be to the right swing. 根據(jù)測出的電阻值大小，可具體分下述三種情況進(jìn)行鑒別： According to the measured resistance value of the size of the specific points of the following three conditions can be identified: A 被測色碼電感器電阻值為零，其內(nèi)部有短路性measured color code inductor resistance value is zero, the internal short circuit 被測色碼電感器直流電阻值的大小與繞制電感器線圈所用的漆包線徑、繞制圈數(shù)有直接關(guān)系，只要能測出電阻值，則可認(rèn)為被測色碼電感器是正measured color code inductor DC resistance of the size and wound inductor coil used enameled wire diameter, winding number of turns is directly related to, as long as the value of measured resistance, you can color code that the measured inductor is normal The. 2  weeks transformer testing A 將萬用表撥至 R1 擋，按照中周變壓器的各繞組引腳排列規(guī)律，逐一檢查各繞組的通斷情況，進(jìn)而判斷其是The multimeter to the R 1 block allocated in accordance with the various transformer windings in weeks pinlaws, one by one to check the windingoff situation, and then determine whether it is 檢測絕緣testing insulation 將萬用表置于 R10k 擋，做如下幾種狀態(tài)測試：will be placed in R 10k block multimeter, do the following several states test: (1) 初級(jí)繞組與次級(jí)繞組之間的電阻值；(1) between the primary winding and secondary winding resistance value。insulation testing. 用萬用表 R10k 擋分別測量鐵心與初級(jí)，初級(jí)與各次級(jí)、鐵心與各次級(jí)、靜電屏蔽層與衩次級(jí)、次級(jí)各繞組間的電阻值，萬用表指針均應(yīng)指在無窮大位置不動(dòng)。 noload current detection. (a) 直接測量法。把萬用表撥至交流電壓擋。 H 檢測判別各繞組的同名端。存在短路故障的變壓器，其空載電流值將遠(yuǎn)大于滿載電流的 10 ％。特別對(duì)初學(xué)者來說，熟練掌握常用元器件的檢測方法和經(jīng)驗(yàn)很有必要，以下對(duì)常用電子元器件的檢測經(jīng)驗(yàn)和方法進(jìn)行介紹供對(duì)考。10％或177。對(duì)于表面無任何痕跡的熔斷電阻器好壞的判斷，可借助萬用表R1擋來測量，為保證測量準(zhǔn)確，應(yīng)將熔斷電阻器一端從電路上焊下。用萬用表的歐姆檔測2(或3)兩端，將電位器的轉(zhuǎn)軸按逆時(shí)針方向旋至接近關(guān)的位置，這時(shí)電阻值越小越好。加溫檢測；在常溫測試正常的基礎(chǔ)上，即可進(jìn)行第二步測試加溫檢測，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。(2)、估測溫度系數(shù)αt先在室溫t1下測得電阻值Rt1，再用電烙鐵作熱源，靠近熱敏電阻Rt，測出電阻值RT2，同時(shí)用溫度計(jì)測出此時(shí)熱敏電阻RT表面的平均溫度t2再進(jìn)行計(jì)算。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。檢測10PF～，進(jìn)而判斷其好壞。電解電容器的檢測因?yàn)殡娊怆娙莸娜萘枯^一般固定電容大得多，所以，測量時(shí)，應(yīng)針對(duì)不同容量選用合適的量程。兩次測量中阻值大的那一次便是正向接法，即黑表筆接的是正極，紅表筆接的是負(fù)極。三、電感器、變壓器檢測方法與經(jīng)驗(yàn)色碼電感器的的檢測將萬用表置于R1擋，紅、黑表筆各接色碼電感器的任一引出端，此時(shí)指針應(yīng)向右擺動(dòng)。絕緣性測試。空載電流的檢測。把萬用表撥至交流電壓擋。檢測判別各繞組的同名端。當(dāng)短路嚴(yán)重時(shí)，變壓器在空載加電后幾十秒鐘之內(nèi)便會(huì)迅速發(fā)熱，用手觸摸鐵心會(huì)有燙手的感覺。檢測判斷電源變壓器是否有短路性故障的簡單方法是測量空載電流(測試方法前面已經(jīng)介紹)。2％。如果超出太多，則說明變壓器有短路性故障,間接測量法。電源變壓器初級(jí)引腳和次級(jí)引腳一般都是分別從兩側(cè)引出的，并且初級(jí)繞組多標(biāo)有220V字樣，次級(jí)繞組則標(biāo)出額定電壓值，如15V、24V、35V等。電源變壓器的檢測通過觀察變壓器的外貌來檢查其是否有明顯異常現(xiàn)象。將萬用表置于R10k擋，一只手將兩個(gè)表筆分別接可變電容器的動(dòng)片和定片的引出端，另一只手將轉(zhuǎn)軸緩緩旋動(dòng)幾個(gè)來回，萬用表指針都應(yīng)在無窮大位置不動(dòng)。對(duì)于正、負(fù)極標(biāo)志不明的電解電容器，可利用上述測量漏電阻的方法加以判別。應(yīng)注意的是：在測試操作時(shí)，特別是在測較小容量的電容時(shí)，要反復(fù)調(diào)換被測電容引腳接觸A、B兩點(diǎn)，才能明顯地看到萬用表指針的擺動(dòng)。測量時(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。此值越大說明光敏電阻性能越好。C注意正確操作。2Ω內(nèi)即為正常。用萬用表的歐姆擋測2兩端，其讀數(shù)應(yīng)為電位器的標(biāo)稱阻值，如萬用表的指針不動(dòng)或阻值相差很多，則表明該電位器已損壞。熔斷電阻器的檢測。讀數(shù)與標(biāo)稱阻值之間分別允許有177。 5%, with a centertapped windings of the two sets of symmetrical voltage difference should be ≤ 177。通常，線圈內(nèi)部匝間短路點(diǎn)越多，短路電流就越大，而變壓器發(fā)熱就越嚴(yán)重。 2 ％。 (b) 間接測量法。 Power transformer primary and secondary pins pins are usually respectively from both sides of the leads, and marked with the 220V primary winding multiword, the subwindings are marked rated voltage value, such as 15V, 24V, 35V and so on. 再根據(jù)這些標(biāo)記進(jìn)行識(shí)別。(6) The resistance is less than infinite, but greater than zero: There is leakage faults. 3 電源變壓器的檢測3. power transformer testing A 通過觀察變壓器的外貌來檢查其是否有明顯異常By observing the appearance of the transformer to check there is an obvious anomaly. 如線圈引線是否斷裂，脫焊，絕緣材料是否有燒焦痕跡，鐵心緊固螺桿是否有松動(dòng)，硅鋼片有無銹蝕，繞組線圈是否有外露等。 In the rotating shaft of the process, if the pointer is sometimes point to zero, indicating movement between the film and the stator shortcircuit point。C for the positive and negative signs unknown electrolytic capacitors can be measured using the above method to determine leakage resistance. 即先任意測一下漏電阻，記住其大小，然后交換表筆再測出一個(gè)阻值。 It should be noted: In the test operations, especially in the measured capacitance of a smaller capacity, they must repeatedly exchange the measured capactance pin contacts A, B two points, in order to clearly see the multimeter pointer swing. C 對(duì)于 0  01 μ F 以上的固定電容，可用萬用表的 R10k 擋直接測試電容器有無充電過程以及有無內(nèi)部短路或漏電，并可根據(jù)指針向右擺動(dòng)的幅度大小估計(jì)出電容器的容量。 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。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