Introduction to general knowledge
Diode detection method and experience
1?奔觳庑"β? Crystal Diode
A? 迸 鹫?, negative electrode
(a) 惫鄄焱 巧 巧 系 牡 。 。 。 。 。. The diode symbol is usually marked on the outer casing of the diode, with one end with a triangular arrow being the positive pole and the other end being the negative pole.
(b)? On the housing of the point contact diode, it is usually marked with a polar color point (white or red). Generally, the end marked with a color point is the positive electrode. Other diodes are marked with a color ring, and one end of the color ring is a negative electrode.
(c) The first measurement with a small resistance value is taken as the positive electrode, and the end connected to the black test pen is the negative electrode.
B? Ben De De Shu M. The operating frequency of the crystal diode, in addition to the relevant characteristics table, is often distinguished by the use of an eye to observe the inside of the diode. For example, a point contact diode belongs to a high frequency tube, and a surface contact type diode is mostly a low frequency tube. In addition, you can also use the multimeter R × 1k block to test, generally less than 1k?
C? Ben è§³åº¾ç½¡å» èš§éž”â”‘ç¼ª 蚧鞔┑缪 RM RM. For AC, because of the constant change, the highest reverse operating voltage is the AC peak voltage that the diode is subjected to. It should be noted that the highest reverse operating voltage is not the breakdown voltage of the diode. In general, the diode's breakdown voltage is much higher (about twice as high) as the highest reverse operating voltage.
2? 奔觳ç 7飧咚俣?
The method of detecting a silicon high-speed switching diode is the same as the method of detecting a normal diode. The difference is that the forward resistance of this tube is large. With R × 1k electrical blocking measurement, the general forward resistance value is 5k? Ting? 10k? stop? The reverse resistance value is infinite.
3? Ben 觳 旎 旎 旎 3 3 ??
The method of detecting a fast recovery and ultrafast recovery diode with a multimeter is basically the same as the method of detecting plastic silicon. That is, first use R × 1k block to detect its unidirectional conductivity, generally forward resistance is 4? 钡 k? to avoid the reverse resistance is infinite; then use R × 1 block to retest once, the general forward resistance is After a few stops, the reverse resistance is still infinite.
4? Ben 觳馑? to the trigger diode
The A? benzene? multimeter is placed in the R × 1k block, and the positive and negative resistance values ​​of the bidirectional trigger diode should be infinite. If the meter is used for measurement, the pointer of the multimeter swings to the right, indicating that the tube under test has a leakage fault.
Place the multimeter in the appropriate DC voltage range. The test voltage is provided by a megohmmeter. During the test, shake the megohmmeter and the voltage value indicated by the multimeter is the VBO value of the tube to be tested. Then replace the two pins of the tube under test and measure the VBR value in the same way. Finally, comparing VBO with VBR, the smaller the difference between the absolute values ​​of the two, the better the symmetry of the measured bidirectional trigger diode.
5? Bi Cai? Voltage Suppression Diode (TVS) detection
A? The smashing cap 硪 × 1k block measuring the quality of the pipe
For the unipolar TVS, the normal and reverse resistance can be measured according to the method of measuring the ordinary diode. The general forward resistance is about 4kΩ, and the reverse resistance is infinite.
For the two-way polar TVS, any red and black test leads should measure the resistance between the two pins to be infinite. Otherwise, the performance of the tube is poor or damaged.
6?Preparation of 渥瓒??
A? Pen 侗鹫?, negative
The difference between the appearance of the high-frequency varistor diode and the ordinary diode is that the color code color is different. The color code color of the common diode is generally black, and the color code color of the high-frequency varistor diode is light color. The polarity rule is similar to that of a normal diode, that is, one end with a green ring is a negative electrode, and one end without a green ring is a positive electrode.
B? Short-selling?, reverse resistance to judge whether it is good or bad
The specific method is the same as the method of measuring the normal and reverse resistance of the common diode. When using the 500-type multimeter R×1k block measurement, the normal high-frequency varistor diode has a forward resistance of 5k???5?钡k? The reverse resistance is infinite.
7? North 淙� Detecting the pole tube
Place the multimeter in the R×10k block. Regardless of how the red and black test leads are measured, the resistance between the two pins of the varactor should be infinite. If during the measurement, the pointer of the multimeter is slightly swayed to the right or the resistance is zero, indicating that the varactor diode under test has a leakage fault or has broken through. For the varactor diode capacity to disappear or the internal open circuit fault, it is impossible to detect with a multimeter. If necessary, the replacement method can be used to check and judge.
8?钡ド? detection
Attach a 1?钡V technology dry battery to the outside of the multimeter and set the multimeter to R×10 or R×100. This connection is equivalent to a 1? 钡V voltage connected to the multimeter to increase the detection voltage to 3V (the LED's turn-on voltage is 2V). During the test, use the multimeter and the two pens to alternately contact the two pins of the LED. If the performance of the pipe is good, it must be able to emit light normally. At this time, the black test pen is connected to the positive electrode, and the red test pen is connected to the negative electrode.
9?Roasting 99.舛?Detection of the pole tube
A? 迸 鸷焱 9 9 9. 舛? The positive and negative electrodes of the pole tube. The infrared LED has two pins, usually the long pin is positive and the short pin is negative. Since the infrared light emitting diode is transparent, the electrode inside the tube case is clearly visible, and the larger one of the inner electrode is the negative electrode, and the narrower one and the smaller one is the positive electrode.
B? Benzene multimeter placed in R × 1k block, measuring the positive and negative resistance of the infrared light-emitting diode, usually, the forward resistance should be 30k? Proximity? Reverse resistance should be 500k? It can be used normally. The larger the reverse resistance is, the better.
10?Roasting postal code? Detection of pole tube
A?
(a)? Beech oil fresh 侗稹 3
(b) The benzene-type multimeter is placed in the R×1k block to check the positive and negative electrodes of the common diode for inspection. That is, the red and black test leads are exchanged to measure the resistance between the two pins of the tube. The resistance value should be one primary school with the smaller resistance value. The pin connected to the red test pen is the negative pole, and the pin connected to the black test pen is the positive pole.
B? å¥”è§³åº‘è§³åº‘èŠŽèŠŽæ€ è›´çŒ›è›´è›´æ·¼ç¼±ç’§é¥¬äº¢ç„±é¥¨é¥¬äº¢ç„±é¥¨é¥¬äº¢ç„±é¥¨?Pole tube positive and negative resistance, according to the size of the positive and negative resistance values, you can initially determine the infrared receiving diode Good or bad.
11? Ben ã™èˆ›? Detecting the pole tube
The A? benzene? multimeter is placed in the R x 1k block. The order of the pins of the laser diode can be determined according to the method of detecting the normal and reverse resistance of the common diode. However, it should be noted during the detection that since the forward voltage drop of the laser diode is larger than that of the ordinary diode, when the forward resistance is detected, the pointer of the multimeter is only slightly deflected to the right, and the reverse resistance is infinite.
Diode detection method and experience
1?奔觳庑"β? Crystal Diode
A? 迸 鹫?, negative electrode
(a) 惫鄄焱 巧 巧 系 牡 。 。 。 。 。. The diode symbol is usually marked on the outer casing of the diode, with one end with a triangular arrow being the positive pole and the other end being the negative pole.
(b)? On the housing of the point contact diode, it is usually marked with a polar color point (white or red). Generally, the end marked with a color point is the positive electrode. Other diodes are marked with a color ring, and one end of the color ring is a negative electrode.
(c) The first measurement with a small resistance value is taken as the positive electrode, and the end connected to the black test pen is the negative electrode.
B? Ben De De Shu M. The operating frequency of the crystal diode, in addition to the relevant characteristics table, is often distinguished by the use of an eye to observe the inside of the diode. For example, a point contact diode belongs to a high frequency tube, and a surface contact type diode is mostly a low frequency tube. In addition, you can also use the multimeter R × 1k block to test, generally less than 1k?
C? Ben è§³åº¾ç½¡å» èš§éž”â”‘ç¼ª 蚧鞔┑缪 RM RM. For AC, because of the constant change, the highest reverse operating voltage is the AC peak voltage that the diode is subjected to. It should be noted that the highest reverse operating voltage is not the breakdown voltage of the diode. In general, the diode's breakdown voltage is much higher (about twice as high) as the highest reverse operating voltage.
2? 奔觳ç 7飧咚俣?
The method of detecting a silicon high-speed switching diode is the same as the method of detecting a normal diode. The difference is that the forward resistance of this tube is large. With R × 1k electrical blocking measurement, the general forward resistance value is 5k? Ting? 10k? stop? The reverse resistance value is infinite.
3? Ben 觳 旎 旎 旎 3 3 ??
The method of detecting a fast recovery and ultrafast recovery diode with a multimeter is basically the same as the method of detecting plastic silicon. That is, first use R × 1k block to detect its unidirectional conductivity, generally forward resistance is 4? 钡 k? to avoid the reverse resistance is infinite; then use R × 1 block to retest once, the general forward resistance is After a few stops, the reverse resistance is still infinite.
4? Ben 觳馑? to the trigger diode
The A? benzene? multimeter is placed in the R × 1k block, and the positive and negative resistance values ​​of the bidirectional trigger diode should be infinite. If the meter is used for measurement, the pointer of the multimeter swings to the right, indicating that the tube under test has a leakage fault.
Place the multimeter in the appropriate DC voltage range. The test voltage is provided by a megohmmeter. During the test, shake the megohmmeter and the voltage value indicated by the multimeter is the VBO value of the tube to be tested. Then replace the two pins of the tube under test and measure the VBR value in the same way. Finally, comparing VBO with VBR, the smaller the difference between the absolute values ​​of the two, the better the symmetry of the measured bidirectional trigger diode.
5? Bi Cai? Voltage Suppression Diode (TVS) detection
A? The smashing cap 硪 × 1k block measuring the quality of the pipe
For the unipolar TVS, the normal and reverse resistance can be measured according to the method of measuring the ordinary diode. The general forward resistance is about 4kΩ, and the reverse resistance is infinite.
For the two-way polar TVS, any red and black test leads should measure the resistance between the two pins to be infinite. Otherwise, the performance of the tube is poor or damaged.
6?Preparation of 渥瓒??
A? Pen 侗鹫?, negative
The difference between the appearance of the high-frequency varistor diode and the ordinary diode is that the color code color is different. The color code color of the common diode is generally black, and the color code color of the high-frequency varistor diode is light color. The polarity rule is similar to that of a normal diode, that is, one end with a green ring is a negative electrode, and one end without a green ring is a positive electrode.
B? Short-selling?, reverse resistance to judge whether it is good or bad
The specific method is the same as the method of measuring the normal and reverse resistance of the common diode. When using the 500-type multimeter R×1k block measurement, the normal high-frequency varistor diode has a forward resistance of 5k???5?钡k? The reverse resistance is infinite.
7? North 淙� Detecting the pole tube
Place the multimeter in the R×10k block. Regardless of how the red and black test leads are measured, the resistance between the two pins of the varactor should be infinite. If during the measurement, the pointer of the multimeter is slightly swayed to the right or the resistance is zero, indicating that the varactor diode under test has a leakage fault or has broken through. For the varactor diode capacity to disappear or the internal open circuit fault, it is impossible to detect with a multimeter. If necessary, the replacement method can be used to check and judge.
8?钡ド? detection
Attach a 1?钡V technology dry battery to the outside of the multimeter and set the multimeter to R×10 or R×100. This connection is equivalent to a 1? 钡V voltage connected to the multimeter to increase the detection voltage to 3V (the LED's turn-on voltage is 2V). During the test, use the multimeter and the two pens to alternately contact the two pins of the LED. If the performance of the pipe is good, it must be able to emit light normally. At this time, the black test pen is connected to the positive electrode, and the red test pen is connected to the negative electrode.
9?Roasting 99.舛?Detection of the pole tube
A? 迸 鸷焱 9 9 9. 舛? The positive and negative electrodes of the pole tube. The infrared LED has two pins, usually the long pin is positive and the short pin is negative. Since the infrared light emitting diode is transparent, the electrode inside the tube case is clearly visible, and the larger one of the inner electrode is the negative electrode, and the narrower one and the smaller one is the positive electrode.
B? Benzene multimeter placed in R × 1k block, measuring the positive and negative resistance of the infrared light-emitting diode, usually, the forward resistance should be 30k? Proximity? Reverse resistance should be 500k? It can be used normally. The larger the reverse resistance is, the better.
10?Roasting postal code? Detection of pole tube
A?
(a)? Beech oil fresh 侗稹 3
(b) The benzene-type multimeter is placed in the R×1k block to check the positive and negative electrodes of the common diode for inspection. That is, the red and black test leads are exchanged to measure the resistance between the two pins of the tube. The resistance value should be one primary school with the smaller resistance value. The pin connected to the red test pen is the negative pole, and the pin connected to the black test pen is the positive pole.
B? å¥”è§³åº‘è§³åº‘èŠŽèŠŽæ€ è›´çŒ›è›´è›´æ·¼ç¼±ç’§é¥¬äº¢ç„±é¥¨é¥¬äº¢ç„±é¥¨é¥¬äº¢ç„±é¥¨?Pole tube positive and negative resistance, according to the size of the positive and negative resistance values, you can initially determine the infrared receiving diode Good or bad.
11? Ben ã™èˆ›? Detecting the pole tube
The A? benzene? multimeter is placed in the R x 1k block. The order of the pins of the laser diode can be determined according to the method of detecting the normal and reverse resistance of the common diode. However, it should be noted during the detection that since the forward voltage drop of the laser diode is larger than that of the ordinary diode, when the forward resistance is detected, the pointer of the multimeter is only slightly deflected to the right, and the reverse resistance is infinite.
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