【正文】 res. D 判別初、次級(jí)線圈。 (2) 阻值為零：有短路性故障；(5) Resistance to zero: There is shortcircuit fault。Rotating shaft with one hand, the other hand lighttouch move the outer edge of the film group should not feel any loose phenomenon. 轉(zhuǎn)軸與動(dòng)片之間接觸不良的可變電容器，是不能再繼續(xù)使用的。 In the test, if positive, no charge reverse phenomenon, namely,needle not move, then lost the capacity or the internal circuit。s red and black table pen and posite pipe, respectively e emitter and collector cphase. 由于復(fù)合三極管的放大作用，把被測(cè)電容的充放電過程予以放大，使萬用表指針擺幅度加大，從而便于觀察。 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。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。 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。 When the shaft rotating handle to its extreme position 3, the resistance should be close to the nominal value potentiometer. 如萬用表的指針在電位器的軸柄轉(zhuǎn)動(dòng)過程中有跳動(dòng)現(xiàn)象，說明活動(dòng)觸點(diǎn)有接觸不良的故障。 For the surface without any trace of the fuse resistor to judge good and bad, can draw support from multimeter to measure the R 1 block, in order to ensure measurement accuracy, should fuse resistor from the circuit welding one end of the next. 若測(cè)得的阻值為無窮大，則說明此熔斷電阻器已失效開路，若測(cè)得的阻值與標(biāo)稱值相差甚遠(yuǎn)，表明電阻變值，也不宜再使用。 10% or 177。 Since Ohm block scale nonlinear relationship, it39。 In order to improve measurement accuracy, measured resistance should be based on the size of the nominal value of the chosen range. 由于歐姆擋刻度的非線性關(guān)系，它的中間一段分度較為精細(xì)，因此應(yīng)使指針指示值盡可能落到刻度的中段位置，即全刻度起始的 20 ％～ 80 ％弧度范圍內(nèi)，以使測(cè)量更準(zhǔn)確。 5%, 177。 If the surface without any trace of the open, this indicates that the current flow is just equal to or slightly larger than the value of its rated fuse. 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(cè)量，為保證測(cè)量準(zhǔn)確，應(yīng)將熔斷電阻器一端從電路上焊下。 Handle clockwise rotation axis and then slowly, the resistance value should be increased gradually, the table header pointer should be a smooth move. 當(dāng)軸柄旋至極端位置 3 時(shí)，阻值應(yīng)接近電位器的標(biāo)稱值。heat detection。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。 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。 Multimeter39。 Actual experience has shown that the leakage resistance of electrolytic capacitors in general should be more than a few hundred k Ω, otherwise, it will not work properly. 在測(cè)試中，若正向、反向均無充電的現(xiàn)象，即表針不動(dòng)，則說明容量消失或內(nèi)部斷路；如果所測(cè)阻值很小或?yàn)榱悖f明電容漏電大或已擊穿損壞，不能再使用。 Will contain the axial front, back, up, down, left and right in various directions and promotion, the shaft should not be loose phenomenon. B 用一只手旋動(dòng)轉(zhuǎn)軸，另一只手輕摸動(dòng)片組的外緣，不應(yīng)感覺有任何松脫現(xiàn)象。(3) secondary winding and the resistance value between the shell. 上述測(cè)試結(jié)果分出現(xiàn)三(1) 阻值為無窮大：正常；(4) The resistance is infinity: normal。coiloff detection. 將萬用表置于 R1 擋，測(cè)試中，若某個(gè)繞組的電阻值為無窮大，則說明此繞組有斷路性故障。此值不應(yīng)大于變壓器滿載電流的 10 ％～ 20 ％。將電源變壓器的初級(jí)接 220V 市電，用萬用表交流電壓接依次測(cè)出各繞組的空載電壓值 (U21 、 U22 、 U23 、 U24) 應(yīng)符合要求值，允許誤差范圍一般為：高壓繞組≤177。否則，變壓器不能正常工作。 All the secondary winding of all the open, the AC current meter placed in block (500mA, string into the primary winding. When the primary winding of the plug into 220V AC electricity, the meter is indicated by noload current value. This value should not be transformer full load current is greater than 10% ~ 20%. the general mon electronic devices power transformer should be the normal load current of about 100mA. If you exceed too much, then power transformer shortcircuit failures. indirect measurement. In the transformer primary winding in series a 10 / 5W resistor, the sub is still all empty. the multimeter to AC voltage block allocation. added power, you use two tables resistance R T measured voltage drop across the U, and then use Ohm39。為了提高測(cè)量精度，應(yīng)根據(jù)被測(cè)電阻標(biāo)稱值的大小來選擇量程。注意：測(cè)試時(shí)，特別是在測(cè)幾十kΩ以上阻值的電阻時(shí)，手不要觸及表筆和電阻的導(dǎo)電部分；被檢測(cè)的電阻從電路中焊下來，至少要焊開一個(gè)頭，以免電路中的其他元件對(duì)測(cè)試產(chǎn)生影響，造成測(cè)量誤差；色環(huán)電阻的阻值雖然能以色環(huán)標(biāo)志來確定，但在使用時(shí)最好還是用萬用表測(cè)試一下其實(shí)際阻值。電位器的檢測(cè)。如萬用表的指針在電位器的軸柄轉(zhuǎn)動(dòng)過程中有跳動(dòng)現(xiàn)象，說明活動(dòng)觸點(diǎn)有接觸不良的故障。(1)、測(cè)量標(biāo)稱電阻值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。若所測(cè)電阻很小，說明壓敏電阻已損壞，不能使用。C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)而左右擺動(dòng)。可選用3DG6等型號(hào)硅三極管組成復(fù)合管。此時(shí)的阻值便是電解電容的正向漏電阻，此值略大于反向漏電阻。將載軸向前、后、上、下、左、右等各個(gè)方向推動(dòng)時(shí)，轉(zhuǎn)軸不應(yīng)有松動(dòng)的現(xiàn)象。 中周變壓器的檢測(cè)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)而判斷其是否正常。線圈通斷的檢測(cè)。當(dāng)初級(jí)繞組的插頭插入220V交流市電時(shí)，萬用表所指示的便是空載電流值。將電源變壓器的初級(jí)接220V市電，用萬用表交流電壓接依次測(cè)出各繞組的空載電壓值(U2U2U2U24)應(yīng)符合要求值，允許誤差范圍一般為：高壓繞組≤177。否則，變壓器不能正常工