How to use a digital meter no capacitance file to measure the quality of capacitance

With a 10K resistor file, the red of the meter pen is connected to the capacitor + pole, and the black is connected to the pole. If the resistance value shows a small increase from very small, first fast and then slowly to infinity, it means that the capacitance is good. If the resistance has been fixed to a very small amount, it has broken down, and if it has been fixed to a very large size, it has been opened.

The digital multimeter needs to have a capacitance file to correctly measure the capacitance value of the capacitor, of course, the measured value must have an error. The quality of the capacitor can also be preliminarily measured with the resistance file of the digital multimeter, the general non-polar capacitor is an open circuit, and the electrolytic capacitor will open the circuit after a short period of resistance, depending on the size of the U number.

1] The capacitor taken from an electrical appliance such as an electric fan must be short-circuited and discharged before the test, otherwise the residual high voltage on it is likely to damage the capacitance meter. You need to test it with an ordinary good capacitor of several micro-methods to see if the capacitance test file of the capacitance meter is damaged;

2] The internal resistance of each resistance file of the multimeter is different, and the internal resistance of a large range is larger than that of a small range. So when you test with the highest range of 2000 megaohms, because the internal resistance of the multimeter is large, it and the capacitor charge and discharge time is longer, you can see the change of the display content, when you use a small range test, the charge and discharge time of the capacitor is short, plus the response speed of the digital meter is slow, so you can't see this process;

3] The capacitor you talked about at the last time will have a smaller value, it may be that there is a problem with the capacitor (but this is rare), could it be that your fingers touch two watch pens at the same time (that is, the insulation between the watch pens is not good)?

With 10k resistor, the red pen is connected to the capacitor + pole, and the black - pole digital meter will charge the capacitor, the resistance value of the capacitor will be reduced, and then the capacitor will be discharged, the resistance value will gradually increase, the larger the capacitance, the smaller the minimum resistance will be. If the resistance value does not move, it means that the capacitor breaks down, and the capacitor breakdown resistance is generally small, and some show infinity to indicate that the capacitor is broken.

Very simple and practical capacitance measurement quality judgment method, multimeter does not have a capacitance file, how to use the resistance file to judge its quality, novices can understand at a glance!

There must be two sockets with capacitance test function, and the positive and negative poles can be connected between the two holes.

A digital multimeter (without capacitance) cannot measure the accurate capacity of a capacitor, but you can use the diode of a digital multimeter (or a switch on and off, most meters are a file) to measure the quality of the capacitance, which means that the capacitor has not broken down.

The two meters of the pen forward and reverse test the two feet of the capacitor, you will hear the call of the buzzer, there is a sound to indicate that the capacitor can be charged and discharged, indicating that the capacitor has capacity, charging in the positive direction, and then discharging in the opposite direction after a while, the length of the sound heard is the same as the immediate discharge in the opposite direction, indicating that the capacitor does not leak. The charge and discharge of the capacitor of the 2A104J should be able to have a slight short call.

Summary. In the past, the pointer multimeter generally did not have a capacitance file to measure the capacitance, and the resistance file of the multimeter was used to judge the quality of the capacitance through the swing amplitude of the pointer and the scale of the position where the swing was located, and then combined with the experience obtained in the measurement process. Later digital multimeters basically had a special gear for measuring capacitance.

There is no need to estimate. But it can also be estimated that the difference is that with a digital multimeter, it is not to look at the swing of the pointer, but to see the change of the numbers. The estimation method is the same.

My multimeter doesn't have a capacitor stop, so I can measure whether the capacitance is good or bad.

In the past, the congratulatory letter of the pointer multimeter generally did not have the capacitance file to measure the capacitance, and the resistance file of the multimeter was used, and the quality of the capacitance was judged by the scale of the pointer swing amplitude and the position of the swing, and then combined with the experience obtained by the old man in the measurement process. Later digital multimeters basically had a special gear for measuring capacitance. There is no need to estimate seepage.

But it can also be estimated that the difference is that with a digital multimeter, it is not to look at the swing of the pointer, but to see the change of the numbers. The estimation method is the same.

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Use the buzzer gear.

Detection uses the buzzer file of the digital multimeter to quickly check the *** defect of the electrolytic capacitor. Figure 5-14 shows the measurement method. Dial the DMM to the buzzer setting, and use two gauge pens to contact the two pins of the capacitor CX under test, you should be able to hear a short beep, and then the sound stops, and the overflow symbol "1" is displayed.

Then, the two meter pens are reversed and measured again, and the buzzer should sound again, and finally display the overflow symbol "1", which means that the measured electrolytic capacitance is basically normal. In this case, you can dial it to 20m or 200m high resistance to measure the leakage resistance of the capacitor to judge its quality.

The principle of the above measurement process is that at the beginning of the test, the charging current of the meter to the CX is large, which is equivalent to the path, so the buzzer makes a sound. As the voltage at both ends of the capacitor increases, the charging current decreases rapidly, and finally the buzzer stops sounding.

During the test, if the buzzer keeps sounding, it means that the electrolytic capacitor has been short-circuited; If the buzzer does not sound and the meter always displays "1", it means that the internal circuit of the capacitor under test is open or the capacity disappears.

With capacitor block measurement, there is a value, good, no value, bad.

It is good to measure for a long time with *1000 gears, and the meter pen is repeatedly changed, and the resistance value changes from small to large.

If there is no capacitor file, use the resistance file to measure and simply look at the charge and discharge of the capacitor.

1. Estimate the capacity of microwave capacitance: it can be judged by experience or with reference to the standard capacitance of the same capacity, according to the maximum amplitude of the pointer swing.

2. Estimate the capacitance of pico-level capacitance: use R 10k gear, but only the capacitance above 1000pf can be measured. For capacitors of 1000pf or a little larger, as long as the watch hand swings slightly, the capacitance is considered sufficient.

3. Test whether the capacitor is leaking: for the capacitor of more than 1,000 microfarnes, you can use R 10 gear to quickly charge it, and preliminarily estimate the capacitance capacity, and then change it to R 1k file to continue to measure for a while, at this time, the pointer should not return, but should stop at or very close, otherwise there is leakage.

4. Adjust the function switch to 20UF or 200UF gear, the pen is in the middle two holes, and the pen will measure the capacitance poles respectively, and then its capacity will be displayed. If it is a used capacitor, it must be discharged before measuring.

1. To judge the polarity, first adjust the multimeter to 100 or 1k ohms, assume that one pole is positive, let the black watch pen connect with it, and the red watch pen connect with the other pole, write down the resistance value, and then discharge the capacitor, that is, let the two poles contact, and then change the meter pen to measure the resistance, and the black watch pen with a large resistance value is connected to the positive pole of the capacitor.

2. Adjust the multimeter to the appropriate gear in ohms, and the principle of gear selection is: 20k gear for 1 F capacitor, 2K gear for 1-100 F capacitor, and 200 gear for more than 100 and F.

3. Then use the red pen of the multimeter to connect the positive pole of the capacitor, and the black pen to connect the negative pole of the capacitor, if the display increases slowly from 0, and finally displays the overflow symbol 1, the capacitance is normal, if it is always displayed as 0, the capacitor is short-circuited internally, and if it is always displayed 1, the capacitor is open internally.

Now the function of measuring the point capacity of the digital strap can directly read the capacity of the capacitor by selecting the corresponding gear measurement! It's very convenient!

It can be tested with a digital multimeter ohmic stop, when the pen is just in contact with the capacitor, the multimeter has a resistance value display, and after a few seconds, the resistance value becomes larger and larger until infinity. This capacitance is good.

Because the capacitor has charging characteristics, it is OK to use the resistor position.

First, adjust the resistance to the highest setting, observe the value, if the capacitor is broken, that is, the capacitor breaks down and is short-circuited, the resistance should be displayed as 0 ohms. If it's not bad, it should be from a numerical value to infinity.