Is it normal for a 400V120uF electrolytic capacitor multimeter to measure a voltage of only 320V?

Is it normal for the above 400V 120UF electrolytic capacitor multimeter to measure voltage only 320V? To solve this problem, we must first determine the role of the electrolytic capacitor in the road, for example, if the capacitor is a filter capacitor, it is basically normal. FYI!

It's normal. The "400V" marked on the surface of the capacitor is only the maximum DC working voltage (the voltage that can work for a long time without breakdown, that is, the withstand voltage value), and the actual working voltage of the capacitor is okay as long as it does not exceed this value.

It's like if your limit is 5 bowls, which means that you don't eat more than 5 bowls per meal, you won't die or spoil, but it doesn't mean that you have to eat 5 bowls at every meal, you can eat 1 bowl of rice, you can eat 2 bowls of rice, or even only half a bowl of rice ,......

Capacitors with a withstand voltage of 400V only work at 320V and are completely normal.

400V is the withstand voltage value of the capacitor, the voltage when actually working should be lower than this value, if the capacitor is exceeded, it may burst off, 320V is the voltage obtained by the mains after rectification, and the voltage will be reduced in the case of load, normal.

The 400V here is the withstand voltage value, not the real original voltage, if this capacitor is connected to the 12 circuit, then the voltage is 12V, what you measure is the DC 320V voltage after the output transformer after the 220V AC voltage is converted to DC, and the pure DC voltage can be obtained after rectification, which is normal.

Answer: The circuit used for this capacitor is a switching circuit, and it is normal to use 120UF filtering after 220V to bridge rectification, and it is normal to measure it to 320V with a meter.

Hello:1, Electrolytic capacitor 400V is itHighest withstand voltage value, and the actual operating voltage is much lower.

2. Measure the voltage value of the electrolytic capacitor on the roadIt has to do with circuits。For example, 220V ACRectification, filteringAfter the voltage, it is alternating currentRoot number 2 times：311v 。

In your case, the 220 should be rectified by the full bridge, and then connected to a 400 volt electrolytic capacitor, because the capacitor plays a flat wave role here, the peak voltage of 220 volts is about equal to about 310 volts.

Summary. The detection steps are as follows: Hello, dear, required material: digital multimeter. First, first use the two poles of the short-circuit capacitor of the gauge needle to discharge (large capacitance needs to be connected to the load discharge, and the small capacitor can be directly short-circuited and discharged).

How to measure the quality of the capacitance of 470+UF+380 volts with a digital universal meter.

The detection steps are as follows: Hello, dear, required materials: digital multimeter. First, first use the two poles of the short-circuit capacitor of the gauge needle to discharge the Yunling power (large capacity needs to be connected to the load discharge, and the small capacitor can be directly and quietly connected to the short-circuit discharge).

2. Insert the digital multimeter pen into the "MA" jack.

3. Point the multimeter to the 600 micro-normal file (when testing the capacitance and resistance, the gear needs to be greater than the value marked with the capacitance and resistance to be tested).

Fourth, the red and black dial hands are connected to the two poles of the capacitor to obtain the capacity of the micro-law car, and the capacity marked on the capacitor is close to the interview, indicating that the fracturing capacity is normal, if the numerical error obtained is too large, then the capacitance is damaged.

Summary. Hello dear, the positive and negative poles of electrolytic capacitors do not need to be measured on the capacitance to know, generally the negative electrode has a negative sign, use the multimeter ohm file 100x respectively to contact both ends of the capacitor, the resistance is very small when first contacting and then slowly increases until infinity, then the capacitor is good, if the resistance has been very small or very large, then it is bad, if the contact is long and the resistance is not infinite, then this capacitor leakage.

Hello dear, the positive and negative poles of the electrolytic capacitor do not need to be measured on the capacitor to know, generally the negative electrode has a negative sign, use the multimeter ohm file 100x respectively to contact both ends of the capacitor, the resistance is very small when the first contact is and then slowly attack Zaohe to become larger until infinity, then the capacitor is good, if the resistance has been very small or very large, then it is bad, if the contact is long and the resistance can not return to infinity, then this capacitor leakage.

Hello dear, the positive and negative poles of the electrolytic capacitor do not need to be measured on the capacitor to know, generally the negative electrode has a negative sign, use the multimeter ohm file 100x respectively to contact both ends of the capacitor, the resistance is very small when the first contact is and then slowly attack Zaohe to become larger until infinity, then the capacitor is good, if the resistance has been very small or very large, then it is bad, if the contact is long and the resistance can not return to infinity, then this capacitor leakage.

How to measure the quality of the capacitance of 470+UF+380 volts with a digital universal meter.

How to measure the quality of the capacitance of 470+UF+380 volts with a digital universal meter, the specific method is as follows: adjust the multimeter gear to a resistance level of 1m; The two pencils are connected to the two pins of the capacitor respectively; At this time, the measured value of the multimeter grip should be: the resistance is small at the beginning, and then the resistance gradually increases until it exceeds the range; Then swap the pen and measure again, and the result should be similar to the one above.

If the capacitor is an electrolytic capacitor, the final resistance may not tend to infinity due to the existence of leakage current during the reverse section, but it does not mean that the capacitor is unqualified, and it should be judged according to the leakage current in the device manual) If the above characteristics are met, the capacitor can be preliminarily judged to be basically no problem. It should be noted that the multimeter measurement method is only effective at low voltage, and does not explain the problem for capacitors with higher operating voltages.

Hello dear, happy to answer your <>

Power capacitors have different functions in different applications, and the specific resistance value used also needs to be determined according to the specific situation. Generally speaking, in a DC circuit, in order to ensure that the capacitor is fully discharged within a period of time, it is necessary to use a resistor to realize the slow discharge of the capacitor. Suppose you want to slowly discharge a 400V, 1000UF power capacitor to 10V, you can calculate the required resistance value by the following calculation:

First of all, according to the RC discharge formula, the discharge time of the capacitor = RC. where r is the required resistance value and c is the magnitude of the capacitance, which is the discharge time muffle. For example, when the battery voltage is 400V, the capacitance value is 1000UF, and the discharge is to 10V, the required resistance value is r = C = 400V - 10V) 1000 UF 5s) = It can be seen that if the resistor used can make the capacitor slowly discharge to 10V.

It should be noted that the above is only a reference value, and the specific use of the resistor also needs to consider the power, withstand voltage and other parameters of the resistor, as well as the complexity and working environment of the specific circuit. It is recommended to refer to the advice of professional technicians when operating.

Summary. If you are going to use an electrolytic capacitor 400V 1000UF multi-use resistor, you can limit its charging speed by connecting a larger resistor in series. The specific calculation method is as follows:

2.Calculate the magnitude of the resistance of the required resistor: Suppose you need to use a resistor r to limit the capacitor charging current, and the rated capacity of the capacitor is c, then there is the formula r = vmax - vmin) *c t, where vmax is the final voltage of the capacitor (i.e., 400V), vmin is the initial voltage of the capacitor (i.e., 0V), c is the capacitance of the capacitor (i.e., 1000UF), and t is the time that the capacitor needs to be charged (i.e., 5 seconds).

Substituting the value yields r = 400v - 0v) *1000uf 5s = 80k. 3.Select the appropriate resistance value for the selected resistor type and range.

In general, two 40 K resistors can be selected and used in series to better distribute power and improve stability.

Well. If you are going to use an electrolytic capacitor 400V 1000UF multi-use resistor, you can limit its charging speed by connecting a larger resistor in series. The specific calculation method is as follows:

2.Calculate the magnitude of the resistance of the required resistor: Suppose you need to use a resistor r to limit the capacitor charging current, and the rated capacity of the capacitor is c, then there is the formula r = vmax - vmin) *c t, where vmax is the final voltage of the capacitor (i.e., 400V), vmin is the initial voltage of the capacitor (i.e., 0V), c is the capacitance of the capacitor (i.e., 1000UF), and t is the time that the capacitor needs to be charged (i.e., 5 seconds).

Substituting the value yields r = 400v - 0v) *1000uf 5s = 80k. 3.Select the appropriate resistance value for the selected resistor type and range.

In general, two 40 K resistors can be selected and used in series to better distribute power consumption and improve stability.

A capacitance measuring 4700uf with a 200U multimeter does not measure the numbers, while a 200U multimeter measures 100uF of electricity.

Not necessarily. It is likely that the maximum range of the capacitor file of the multimeter is less than 4700uf, so the actual capacity cannot be measured. I don't know what brand of the 200U multimeter you are talking about, but the brand can check the maximum range of the capacitor file for you.

Nominal copy 330UF 200wv electrolytic capacitance, withstand voltage is 200V!

Note: 1,330uf is the nominal capacity of the electrolytic capacitor.

2. The "W" in the word 200WV is the abbreviation of "work" in English. "WV" refers to the operating voltage, which means that the maximum continuous operating voltage of the capacitor is 200 volts.

The capacity is 330U, the withstand voltage is 200V, W is the prefix of English WORK, the meaning of WV working voltage, there is no special meaning,

200wv

means that the maximum continuous operating voltage is.

200 volts. w stands for working, working voltage. working

voltage

Use the resistance ohm file of the digital multimeter, and discharge the measured capacitor before testing to prevent damage to the digital multimeter. The two stages of the capacitor are not connected, and it is best to connect them with appropriate resistors.

Capacitance measurement: Use the resistance gear to select the appropriate range according to the capacitance capacity, and pay attention to the positive electrode of the capacitor for the electrolytic capacitor black meter pen when measuring.

Estimate the capacitance of microwave capacitance: It can be judged by empirical or reference to the standard capacitance of the same capacitance, and according to the maximum amplitude of the pointer swing. For example, a capacitor of 100 F 250V can be estimated with a capacitance of 100 F 25V, as long as the pointer swings the maximum amount, the capacitance can be determined to be the same.

Estimate the capacitance of pico-level capacitance: use R 10k, but only 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.

Test whether the capacitor leaks: for more than 1,000 microfarnes, you can use R 10 gear to quickly charge it, and preliminarily estimate the capacitance capacity, and then change to R 1k gear 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. For some timing or oscillation capacitors below tens of micromethods (such as the oscillation capacitance of color TV switching power supply), the requirements for its leakage characteristics are very high, as long as there is a slight leakage, it can not be used, at this time, you can use the R 1k file after charging, and then use the R 10k file to continue to measure, the same watch hand should stop at the place and should not return.