Can you touch a capacitor
How to check small capacitors. Check the capacitor by a multimeter and measure the container. Check for non-polar constant capacitors
Sometimes it is necessary to check electronic items, including capacitors.
For various reasons, capacitors can fail, it can be an internal short circuit, an increase in the leakage current of the capacitor in the study of exceeding the maximum allowable voltage. Or or the usual decrease in capacitance is why almost all electrolytic capacitors understand with the passage of time.
Capacitor verification methods, we'll look at, pretty simple, here the most important skill is using the tester or multimeter and correctly applying this instruction.
First you need to know that all capacitors are divided into polar and non-polar. The polar includes electrolytic capacitors, all others are non-polar.
Polar capacitors in the scheme should be so standing that there was a negative power on the indicated minus of the output and on the positive contact plus, just so that it is no different.
If the polarity is violated then the minimum that this capacitor fails, but with sufficient voltage it will crash and explode, in order so that in an emergency the capacitor is not broken into fragments, in imported capacitors, in the upper part of the case made of a fine material and special separating slots are deposited, when the explosion just pops up such a capacitor and does not touch the elements around itself.
Before you check the capacitor, you definitely need to be discharged Every metal compartment snorts its conclusions and so before every check.
If the tested capacitor is on the board, it is necessary to release at least one conclusion from the scheme and then proceed with the measurements. Since most modern capacitors have a fairly low landing, it is better to drop a full capacitor.
Check the capacitor multimeter
With the help of a multimeter, you can check almost any capacitor by capacitance greater than 0.25 microfarads.
The polarity of the capacitor is indicated on the case in the form of an ownership ribbon with a minus sign - this is a minus cooler trigger.
So put the tester in mode or calls or resistance. Multimeter in this mode has a constant voltage on its scythes.
We touch the contacts of the capacitor contacts and see how the resistance indicator grows smoothly - the capacitor is charged.
The charge rate is directly dependent on the capacitance of the capacitor. After a certain period of time, the capacitor charges and the multimeter reads the value "1" or in another way "Infinity" already says that the capacitor does not break and does not climb.
However, if you, when you touch the contacts of the capacitor contacts, we immediately observe the value of "1", then this indicates the internal pause - the capacitor does not work.
Another one also happens, the value "000" or a tight very small value that does not change (when charging) Sometimes the multimeter beep, it says about the breakdown or short circuit of the plates inside the capacitor.
Non-polar capacitors It is fairly checked, the tester is set to the measurement mode of the resistance (megaoma) touching contacts of the capacitor contacts - the resistance must be at least 2 MEG. If there is less, then the capacitor is observed, but make sure you haven't touched the fingers of the probes at the time of the measurement.
Check the arrow device. The essence of the check is the same as a multimeter, but here you can already clearly observe the process of charging the capacitor, since we can see the deviations of the arrow and non-flashing numbers on the display.
Checking the capacitors with the arrow tester
A good capacitor when contacting the ships, do not forget to derive, reject the arrow first, and then slowly and gently return the arrow, the speed of the arrows depends on the capacitance of the capacitor.
If the arrow does not deviate or is released, it does not return to tell the apparent malfunction of the capacitor.
However, if the capacitance of the capacitor is very small, then "charge" can not be noticed - almost immediately the arrow turns into infinity, that is, it will not move from the place. For the capacitor, more than 500 microfoils - such a picture, will almost immediately speak about the internal pause.
A good way will be to test an apparently good capacitor (for clarity) and compare it to the subject. That way, it creates an opportunity to confidently answer the question - is the capacitor working?
Variable voltage check.Since it is impossible to observe such a rapid charging process capacitors check low capacitance There is a special way that it can be determined with accuracy that there is no breakdown.
A small scheme consisting of a sequentially connected capacitor, an AC ammeter and a Zahn limit value resistor is assembled.
The connected circuit is connected to the source. AC voltage, with voltage not exceeding 20% of maximum capacitor voltage.
If the arrow on the amperometer does not deviate, it indicates the internal cut of the capacitor
Check capacitor capacityTo test the capacitance we need to make sure that the real capacitance of the capacitor is what it says on its package.
All electrolytic capacitors over time (during operation) "dry out" and lose their capacity, this is a natural process, and for each specific scheme there are certificates and deviations.
Check the container with a multimeter in "CX" mode, select an exemplary container with a maximum limit.
The capacitor is made from a metal object, e.g. B. Tweezers and insert capacitor tests into the socket, discharged.
For more accurate readings it is necessary to ensure that there is a new and non-rational "crown" in the multimeter.
Dedicated equipment is used for an external similar multimeter that specializes specifically in the testing of capacitors and has a wide range of capacitance measurements, from picophade units to tens of thousands of microfarads, not every professional multimeter and half the tank.
However, if you don't have a multimeter in hand, you can roughly measure the tank by the arrow omeme.
As mentioned above, the capacitor touches its contacts to its contacts - "We perturb the time of the rejection of the arrows and compare the time with an obviously good (new) capacitor, if the time is not very different, then the container in the normal range and the capacitor works.
The same way you can determine the capacitor leakage current. To do this, the capacitor is charged back to the deviation of the arrows.
With an interval for a few seconds (depending on the container) the probe is reapplied, if the arrow does the same all the way, then it says subsequently increased current leakage and already partial capacitor failure. In the right capacitor for a few seconds, the greater the capacity, the longer the "charge" needs to be stored, and the arrow should initially no longer show as low a resistance as it did on the first charge.
"Charge the voltage".
This method of checking a similar situation is suitable for more high voltage capacitors, since the whole situation cannot be understood on a low voltage (by the tester).
And so the essence of the way that the capacitor is charged from the source constant voltage, for this the voltage is chosen a little less than the maximum, and the contacts of the capacitor, as a rule, are charged for 1-2 seconds. After that the "charging" is disconnected and the multimeter measures the voltage at the contacts of the capacitor, it should be almost the same if it is used during charging, if it is not so very inconspicuous, then a high leak cooler is defective.
The multimeter has been observed for some time voltage, the capacitor wakes up smoothly, loses the voltage, the speed wakes up on the tank and the ESR (internal resistance).
How to check the condenser without instruments
In some situations with the absence of an ohmmeter or voltmeter serviceability electrolytic capacitor it can only be checked with the availability of the appropriate source. The capacitor is calculated for 1-2 seconds, and then you need to close it with a metal screwdriver.
A good capacitor has a bright spark. If it is faint or barely noticeable, it suggests that the capacitor is faulty and does not contain a bad charge.
Before talking about capacitor testing, let's touch the theory of the question: what are these components, what are they used for?
The capacitor is therefore a passive electronic component, working on a battery principle that is able to charge very quickly and take on itself, thus a certain amount of energy. BOLE can be formulated scientifically as follows: The capacitor is two conductors (plates) that are separated by an insulator and are used to accumulate charge and electrical field energy.
Note: Plates (conductors inside the housing) can be made of different materials, different shapes and thicknesses. Same goes for the isolator between them. The essence of the matter does not change.
Briefly consider the principle of the capacitor. Under normal conditions, all substances (including conductors) are electrically neutral. What does that mean? And the fact that in their structure there is approximately an equal amount of electrons (negatively charged particles) and protons (positively charged). Since we are applicable to this topic, we are interested in the conductor first, then we will look at them.
So, in the conductor there are many chaotic moving particles that travel between the atoms of the substance, like air molecules in space. When you surround this piece of fabric with an electric field, these particles react by pulling on the poles. Negative (electrons) collects on one pole and positive (protons) - in the other. It is necessary to remove the field, and the charged particles are again dispensed with in the entire volume of the substance and are evenly mixed.
Now imagine such a situation: before we remove the field, we are going to cut this "substance" (split) into two parts. What happens? Particles with different fees will be "locked" in each of the halves! In each of the halves, one of the charges will be dominant, that is potential It will be positive or negative. BUT voltage will be called difference between the potentials of both halves.
Now is the most interesting thing: if you connect the conductor to two of our insulated halves, with a voltage between them, then the conductor will lead the electrically charged particles on top of each other to mix evenly. So the principle of operation of the capacitor looks like this :)
We continue! Depending on the state of the electrolyte inside and the material outside (from which they are made), capacitors can be dry (solid), liquid (electrolytes), oxide semiconductors, oxide metal. Depending on the dielectric (insulator): paper, metal cleaners, film, combined paper, fine-layered organic synthetic films.
All this variety of implementation means that we have a fairly wide range of capacitors and their types.
We're interested in electrolytic capacitors first as it is most likely to be checked by a multimeter.
The capacitance of the capacitor depends on the area of the conductors and the distance between them. What they are closer to each other, the larger the container. The container is measured in "farads". But it has been a lot since Faraday, then everyone decided to measure the capacitance capacitors in microproaids (MF). In order to achieve large capacity (with a relatively small size of the element) you must try to defy! In the miniature case, we need to place conductors with a larger total area, to save the space, divide them as a thin layer of the insulator.
The thin aluminum foil is used as a plate (conductor). Two foil tapes are tight and folded into the roll. Therefore, they interact not only in their environment, but also on both parties. The foil is covered on one side by the microscopic oxide layer, which acts as an insulator, on one side.
Between the foil strips is a special (very thin) paper that is impregnated with an electrically conductive liquid (electrolyte) (electrolyte). The liquid measured the foil, which is closely adjacent, so that, despite the presence of paper, the capacitor turns out to be that the capacitor is only separated by a few oxide molecules. Here, at the expense of all these tricks, such a large container is highlighted in such a relatively small product size.
We are said schematically, can be displayed as follows:
Note: The total capacitance can be increased by parallel inclusions (connections) on the circuit board. This non-cunning move combines the capacities of all the capacitors on it. It is also necessary to take into account the fact that the container can vary depending on the state of the dielectric. For example, if the isolator falls, the element's container will decrease.
Add a few notes about the above system. Often times you can hear the terms "cathode foil" and "anode foil". The cathode is a negatively charged conductor and the anode is positively charged.
Remember that at the beginning of the article we remembered that we talked about the fact that the particles in their charge are attracted to different poles of the substance? This is it: cathode and anode foil (negative and positively charged conductors). The scheme also does not show the rubber seal (it is immediately after the end of the capacitor). In the photo below - several disassembled tanks, on which it is clearly visible.
So we talked about what capacitors are, how they work and how they are arranged. Now consider what are their functions?
Their two main functions:
- conservation and support. electric charge
- stress smoothing in the electrical circuit
Consider each of the articles in more detail. As we recall, the capacitor can accumulate (charge) and charge (discharge) very quickly, then it can compensate for a short-term loss of voltage in the nearby electrical circuit node.
Let us give an example: You may have seen the situation in which there was a brief voltage surge in the power grid in a room with a large number of computers. The light, while speaking in people, "blink". After that, almost all computers usually restart, but some work as if nothing happened! This will primarily be due to high quality capacitors in them. Of course, with the complete absence of power on the network, at least for a few seconds, all computers are turned off. There are no more, even if the most wonderful capacitors do not help, and do not need full-fledged - oops.
In the work process in "Debryes" system block Our computer has such situations: One of the components of the PC, when you are performing a task, you should briefly need more energy. To take it from the power supply "Long" (necessary here), and the wires for which the current has its own coefficient of resistance, which also does not contribute to the installation of the pulse in the desired place. This is where capacitors nearby come to the rescue. You can discharge to ensure the necessary power and gain a charge almost instantly.
Second characteristic: stress smooths out on the network. Will decipher this case. A high quality capacitor is an excellent suppressor of high frequency (HF) and low frequency interference (LB), all types of wave and voltage jumps. The interference often results, for example, parallel work in an electrical network Other devices: fans, air conditioning, heating, etc.
The capacitor is often used as a filter (for smoothing voltage pulsations). Hence, it is often possible to hear the phrase "smoothing capacitors". Almost always as filter capacitors are used in power blocks in personal computers. As we recall, it has a frequency of 50 Hertz (the direction of electron movement in this case changes in 1 second in this case).In terms of computer nutrition, this is a completely unacceptable situation!
Before proceeding directly to smoothing the pulses, the voltage (from the variable to convert to constant) must "guess" (from the variable). As we remember previous materials, it is the "life" in ours. To convert the voltage inside the power supply, use a rectifier circuit, which consists of a power transformer, rectifier and filter on its power. In the role of the last and the capacitors that smooth the components of the remaining variables.
Well, finally we are approaching the main topic of our article: checking capacitors with a multimeter. Believe me, it is faster to show all of this in several short videos (which we will do below) than to write a lot of text. That is why it turned out such a heroic accession, otherwise the article would be small small :)
So we are going to list the main malfunctions of capacitors. They can be differentiated into five:
- Loss of the tank (drying)
- Increase the current leak
- Increase in active resistance (ESR)
We will not go into great detail, we will only list those that have been found most often. I will describe and show how I do, maybe someone checks the capacitors differently?
Take two non-working items in your hand. Well if not workers? They are exactly what they work for, but the whole question is how? In the photo below, one of them is clearly out of order (right), but the left one is normal (in appearance), but has absolutely the same problem as the "neighbor" - loss of the tank. As a result, the capacitor "does not hold charge".
The guaranteed life of the electrolytic capacitor means that the regular (nominal) container does not exceed the permissible (calculated) deviation during the specified period. As a rule, such a deviation is no more than 20 percent. The excess in the life of the element does not mean that it basically ceases to work. He will continue his work, but his capacity will not be within the specified limits technical documentation, and this, as we understand, is not good and can lead to various unpleasant consequences over time.
See the photo below. It shows the digital scoreboard on my multimeter, which I usually use to check capacitors. We understood in one of our previous articles, so we will not repeat ourselves.
Let's do that: first I will briefly describe what and how to prepare measurements to build on the multimeter, and then duplicate the whole process in a little video. I think that will understand and be clear? I start checking from a working item (reference sample), and then back to our "Experimental" from the above photo above.
I check the capacitors in "Clear" mode for a short circuit (the position on the multitetester board under the number " 1 In the absence of this mode, you can transfer the device to the resistance measurement status: the symbol in the photo below is applied to the triangle. It is possible to carry out the measurement on the bends on 2 Kiloma (2000 Ohm or 2k). The photo shows under the number " 2 ».
Multitester prepared for work. What do we have to do next? Black (minus) appliance probe that is applied to a negative conductor and a red (positive) to its positively charged pole. This is how to find out the polarity of the capacitor we wrote so we won't repeat. In principle, if you confuse something terrible, it will not happen :)
Applying the probe to the conclusions (legs) of the capacitor, thus apply to charge it. On the multimeter display board at this point we see the increasing numbers (the element resistance value). When the indicators of the allowable limit of measurement of the multimeter itself come out (in this case, two megaoms are: 2m.), we see the screen number on the right side of the numeric screen. 1 ».
Similar "behavior" of the multimeter and means that the capacitor test was successful and it works. Hold the probe on it for some time (10-15 seconds) to finally charge it. Now you can translate our measuring device into measuring mode. direct current (there will be enough limit on 20 volts) - circled with a square in the photo above and "Remove" remove the charge centers from the conclusions.
Note: With a cheap digital multimeter charge it can be three volts (a little more or a little less). On our measuring device at work, we calculate them up to seven volts and above. If the voltage reading is within a volume or less, it can say that the container should not be charged and replaced.
To discharge the capacitor (before the repeated test or installation at the charge), simply use something metallic (it is possible directly with one of the probe) closer to each other of its "legs", as shown in the following photograph.
Well, as agreed, I'll post a couple of little videos showing what we described above. Let's start with a working (reference) article:
Note: After the correct measurement, it is necessary to guide yourself without touching the conclusions with your fingers (so we introduce the error in the final result due to the resistance of your own body), but for example it is born :)
Now check the capacitor which is not working. Remember that green, with a puffy lid?
Please note that we are testing it in resistance measurement mode with a 2K value (2000 Ohm) on the scale. Do you see how slowly (compared to the previous one) is raised? At some point this process just stops and even begins to go in the opposite direction (it is discharged). This is a bright sign of malfunction!
Now we will check the capacitor multimeter, which seems to differ from the usual ones (none of the bottom there is no characteristic weakness, electrolyte outlets, etc.) also pay attention to the result of the voltage measurement after it is charged - only 0.56 volts cuts
You may ask: is there a prevention of capacitors to prevent their premature failure? The answer will be: exists! The life of the electrolytic capacitor can be relieved quite significantly by reducing its operating temperature. The regularity is approximately as follows: the time of "life" (good work) of the element is increased twice with a decrease in its operating temperature for every 10 degrees Celsius. Remember, an avoided thing! Burn with him mercilessly! :)
Note: The rule described above is only valid at 40 degrees. The decrease in temperature does not lead to such a tangible effect.
After you checked everything, just click on a new one (obedient).
I would also like to introduce you to a very useful device that is ideal for working with capacitors in radio-electronic equipment. It is called " ESR-Micro V4.0s».
Note: ESR - (equivalent series resistance - equivalent sequence resistance - EPS) - one of the parameters of the capacitor that characterizes its active losses in the chain.
Often there are no complaints with a purely visual to the element: it is not swollen, it looks good, but in fact it is faulty (partially lost the container, has a high leakage current, etc.). Here we use a similar wonderful tank meter ESR-Micro V4.0s. Interesting is the instrument taking measurements without having to dismantle the container (depositing) the container from pCB!
Attention! Before checking the ESR counter (installing the item directly into the device), you should discharge it by closing the conclusions. Otherwise, there is a chance that he will retain the accumulated charge, discharge the meter itself! And it can fix the device. This is especially true for high capacity elements.
At work we use the simplest such testers: " GM328A."(It's worth ten dollars, it's powered by a 9-volt type of Crown battery.) It can measure both capacitance and ESR capacitors and three-way transistors, resistors, diodes, etc. That Photo below is an example of the measurement:
We measure the capacitor with a capacitance of 220 microfarads (see that on the tester - 118MF - almost twice less), we also see ESR (loss) 9.6 - this is very much for this nominal point, and the value of vloss 9.9% is also overrated. Yes, in the photo we have adapted to the measuring device to provide a kind of connection from the monitor to fix it in IT elements with short "legs" (outputs), as they cannot always clamp in the fixation module of the tester itself.
To navigate the tolerances of the ESR yourself, - below the summary table, where it is displayed: Which value of the tension element should correspond to the leakage value.
Finally a few words about such a malfunction of the element as a breakdown. In this case, check the capacitor through the multimeter very simply: in the "Correspondence" mode we apply the probes to their conclusions, and if you hear a characteristic squeak - in the garbage! One of the conductors is damaged or the insulation layer between adjacent plates is defective. The element is clearly subject to replacement!
Below - a small video that is more detailed of ESR counters.
Multimeter is a functional device that combines the functions of three measuring devices at the same time - an ohmmeter, a voltmeter and an ammeter. The universal tester is used for voltage measurements, current and resistance forces on the plots of the chain.
An integrated element of the electrical circuit of any instrument is a capacitor, which is two conductive plates of opposite polarity separated by a dielectric. The main functional purpose of the element is to accumulate electrical energy and smoothing voltages in the electrical circuit. A bipolar device is used in industrial electrical and radio engineering which are used to create chains and vibration contours to get a powerful pulse to store digital and analog signals.
Types of capacitors.
Capacitors can be made in the form of a cylinder or as a flat element. For this purpose, a distinction is made between these device types:
- low voltage;
- high voltage;
Based on the type of dielectric:
- silver mica.
Capacitors are also divided by the ability to change the size of the container. There are three groups of devices:
- with constant capacity;
- variable capacitors;
Capacity is a key characteristic that defines the time it takes for the device to 100% charge and discharge after the electrical devices are connected to the utility grid. The indicator of energy accumulation depends on the distance between the conductors and on their area. Unit of measurement - microfrave, pycofarades.
Video about capacitors.
How to measure the container
Traditionally, the capacitor case contains a mark indicating the three main values that define the type of two-pole device, these are:
- operating voltage;
- permissible deviation of the tank value
In cases where there is no marking of the case, or the need does not arise, not to learn the nominal, and the actual indicators can be measured by the capacitor capacitance through a multimeter. Analog and digital models are used to measure electrical parameters.
Consider the process of measuring the capacitor with a digital device. The digital multimeter is a case equipped with an information card, a regulator for changing the measured values, for measuring indicators.
In order to determine the actual container by means of a multimeter, which is equipped with a corresponding function, the radio element is connected to the measuring device. The instrument controller is switched to the most accurate range of the tank measurement. When the disclosure notice appears above the digital score, the position of the slider will change. Switching measuring ranges until the digital value is displayed on the screen.
Important! In fronthow to measure the capacitor capacitor multimeterIt is necessary to determine the type of article. Polar devices, which mainly include electrolytic capacitors, are soldered to the electrical circuit contacts in accordance with signs of charge, that is, positive to positive, minus the minus. When measuring the accumulated energy of electrolytic capacitors, the connection of the digital meter terminals is also carried out in accordance with the rules of polarity. When checking the non-polar ceramics, saliva, paper capacitors, the order of the terminals did not.
How to measure the capacitance of the capacitor by a multimeter that has no function of determining the accumulation of the device? A billing method is used. To find out the indicator, you need a standard signal generator. The measuring process occurs in the following sequence: a certain amplitude of the signal is installed on the generator within a few volts, measuring device transfer to the operation of the micro- or milliampermeter of the alternating current. Consistently plug in the multimeter, the generator and the verifiable object. Conduct the frequency setting until the current reaches 200 MCA (in microamer mode) or 2 mA (in milliammeter mode). After measuring the specified parameters, go to the calculations.
The amplitude voltage value is divided into √2 to get the actual parameter. The capacitive resistance (in OM) is obtained by dividing the readings of the voltage into the current value in amperes. The capacitance of the capacitor is calculated by the formula C \ u003d 1 / (2πfr), where:
C - the capacitance of the element (f);
f - frequency (Hz),
R is capacitive resistance (OM).
To check the polar capacitor through a multimeter, without determining the capacitance of the capacitance, it is necessary:
- know the legs of the sparkling element to remove the charge therefrom;
- install the multimeter switch in the "Sneakers" mode;
- the surfaces of the device probe condensing with respect to the condenser;
- hold the probe to explore the instrument readings.
If the capacitor with a nominal capacity of more than 0.2 μF is responsible, the display will first show the resistance value and "1" after the figure. If the number "1" appeared on the monitor immediately when it was applied to the probe to the element inferences, there is an internal pause. The appearance on the display numbers "0" indicates a seal between conductive plates.
Diagnosis of non-polar capacitors by a multimeter is carried out by measuring the resistance value. The radio element is as good as the certificate of over 2 Mega, a lower value indicates the failure of the element.
Important! When taking measurements, you should avoid hand contact with the applications of the device in order to avoid distortion of the measurement results.
In summary, I would like to register, the multimeter is a useful domestic device that allows you to test items on your own electrical systems and measure the determinative properties of electrical equipment.
The failure of such a seemingly simple detail as a capacitor often leads to a breakdown in electrical engineering. To determine its serviceability, it is not even necessary to study the basics of electrical engineering, it is enough to check the multimeter capacitor, after which it is not difficult to restore the power of the microwave or refrigerator.
Before repairing the repair, you need to determine which item is faulty, for this we will need a digital multimeter as shown in the image below and the soldering iron.
How to measure the basic characteristic (capacity)
Not all capacitor malfunctions can be tested in an OHMMETER mode such as cutting. And if the multimeter shows an infinitely large resistance of the polar element, which can be a clear sign of its malfunction (provided the connection is properly connected), then this method is absolutely not suitable for non-polar radio components.
Check that the loss of nominal capacity is not possible in module mode. In this case, do not do without a device with which you can measure this characteristic. As a rule, digital multimeters allow testing from 20 NF to 200 μF, which is actually enough to diagnose.
A multimeter with this feature can test all capacitors, including electrolytic ones, when checking the latter, the polarity should be observed.
Video: how to check the capacitor
To check it is enough to insert the outputs of the part in the CEL socket and set the instrument switch button to the required range measurements, after which the parameters of the container are shown on the display.
Malfunctions and causes of their occurrence
Regardless of the type of capacitor paper or high voltage, it can fail due to the following errors:
- reduction in nominal capacity as a result of drying;
- the leakage current exceeds a certain value;
- increase in active losses in the chain;
- short closure of panels (insulator collapse);
- Loss of contact between edge and part output (open).
The errors described above can occur as a result of violations. temperature mode, exceeding the threshold of allowable voltage, mechanical damage, etc.
Note that lowering the operating temperature can greatly expand the service of almost any radio element. In most cases, overheating is the main cause of radio component breakage.
If practice shows, the capacitor failure is most often due to the short circuit of the plates, ie we break. Let's tell you in detail how to diagnose in this case.
It is possible to detect a collapse of the sparkle element based on visual inspection for a characteristic flatulence, obscuration, cracking, or other housing integrity disturbance. As an example, such signs are shown in the photo.
To visually detect the non-working radio element, it is not always successful, it is quite normal that the part that has a whole body that does not have pronounced defects that cannot work due to the internal short circuit.
Before you start checking a multimeter, non-polar film, ceramic, electrolytic, SMD or SBB capacitor, it should be removed from the board as it is not possible to test without falling radioetals.
For justice it should be noted that there are several ways not to resort to the soldier, one of them is to measure the resistance of the chain on the board, but for this you need a resistance card, and for certain model a broken device, and it is also not always there in official service centers.
Diagnosis of non-polar devices
When checking a multimeter, we do not need to measure the capacitance of the non-polar capacitor, it is enough to measure its resistance, it should be infinitely large. In the event of a breakdown, the device shows its insignificant value, that is, the part behaves as an ordinary electrical conductor.
Priority action in testing as follows:
- it is necessary to set the maximum measuring range in module mode;
- the devices of the device touch the conclusions of radio components (taking into account the type of capacitor, it is not necessary to observe polarity);
- if "1" is displayed on the display panel, it indicates that the measured resistance is more than two megapiles, therefore the part is correct, otherwise the multimeter will show any value that means a short circuit within the radio component.
Important moment! When being measured, do not hold the probe device up for non-isolated places, as in that case the testimony will be unreliable, you will simply measure the resistance for your body.
The test can also be carried out in the mode of checking the diodes, in this case, if there is a breakdown, the device will indicate a short circuit with a characteristic beep.
Diagnosis of polar capacitors
Polar-type capacitors (electrolytics) are tested in the same way for the same, except that the measurement threshold should be more than 100.
Before the diagnosis, it is necessary to discharge a radioetal, it is enough to connect the conclusions. The high voltage capacitor is preferably "short circuit" through the load, it can be the resistor or a common incandescent lamp.
Without removing the charge, there is a high probability of spoiling the multimeter, in addition to touching the conclusions through the open part of the body, you drain the capacitor by yourself, and this is quite an uncomfortable feeling.
In fact, the presence of sparks during discharge is enough to show that the device is working properly.
To check the multimeter of the capacitor, connect the probe (it is necessary to observe the polarity), as a result, the electric current coming from the device accumulates in the test part. During this process, the multimeter will first indicate an increase in resistance, which indicates its health.
Note that it looks more obvious on analog meters, especially on the shooting of ohmmeters. The speed at which the arrow deviates allows you to judge the container as the longest process, the more.
The method of checking the module mode is related to the indirect, to get an accurate estimate you need to use a digital multimeter that allows you to measure the container, such as the DT890B + model.
Repair of household appliances
The performance of capacitors properly causes household appliances to stop working. The testing technique described above determines the defective part. After it is detected, it is enough to replace the faulty element in order to restore the operability of the TV, microwave oven or vacuum cleaner.
Knowing how to check the capacitor multimeter, you can check how much the start-up element in the automobile generator or the failure of the traverse detects.
Attention! Before you start repairing electrical equipment, you need to make sure that it is turned off from the power supply. Manipulation with stress devices can lead to electric shock.
How to check the electrolytic capacitor multimeter
All loading gears are roughly the same, just with different materials. For example, electrolytic capacitors have two plates made of aluminum foil (electrodes) and between them dielectric, material with greater resistance.
As the dielectric in electrolytic capacitors, the paper of electrolyte is used, and for non-polar film capacitors, the dielectric is ceramic, glass. The paper resistance is lower than the ceramic, so that electrolytic capacitors have a higher leakage current (self-discharge) compared to charge film drives.
If the plates close, heat is highlighted, the electrolyte evaporates and an explosion occurs, turning all the insides of the charge engine. To prevent electrolytic capacitors from exploding, the cross is extruded at the end of its housing. When the electrolyte boils, the end end of the case along the cross and the electrolyte pair will run out without breaking the case.
Therefore, some defective capacitors have exhaustion formed at the ends of the case. In the type, capacitors are divided into polar and non-polar. Polar electrolytic capacitors only work with the correct positive and negative connections with the marked capacitor terminals. Otherwise the charge storage has failed.
There are also electrolytic non-polar capacitors that are designed in alternating voltage networks. Film shoots belong to non-polar containers. Compliance with polarity in the schemes is not necessary for them. The condition of the capacitor is checked by a multimeter for resistance or in the measurement mode via some multimeters (if there is such a mode).
The resistance of the dielectric electrolytic capacitor varies by 1 mΩ between 100 com. Before checking the electrical capacitor, you need to derive it. If there is a capacitor of small capacity, then it is possible to dissipate it by closing the metal screwdriver. If the container is large and the voltage rating is high, discharge the drive through a 10 com resistor, with the resistor holding up against the tool with insulated handles.
The declaration of capacitors must be safe (especially high voltage) and maintain the operation of the multimeter. The remaining voltage on the drive can easily bypass the meter. When checking the electrolytic polar capacitor, the probe multimeter is applied to its connections according to the polarity, plus the device to the memory plus.
The value of the measured resistance on the instrument is made from 100 kΩ to 1 mΩ depending on the size of the tank. To measure a large capacitance, the measurement limit of the resistance 1 MΩ is set. At the beginning of the measurement, the multimeter shows a small resistance, which reaches the highest value when the capacitor is fully charged. If the display shows zero, it means the failure of the tank in short closure, and the device indicates a pause in the conclusions.
Capacitance performance can be checked if you charge it from the power source and measure the value of the drive voltage by a multimeter. When its operating voltage is 25V, charge the container in accordance with the polarity from the source from 9-12V. The readings on the display are removed at the time of touching the probe on the conclusions of the container, as the container begins to discharge through the multimeter and the voltage drops.
How to check the capricious non-polar ceramic capacitor multimeter
The electrolytic non-polar capacitor is used in the starting scheme of single-phase and three-phase electric motors in a single-phase network. This capacitor can be checked by a multimeter as an electrolytic polar charge drive. For him, the polarity of the multimeter matters when the tests of performance does not matter. They are checked on the same measurement of resistances as polar containers.
Check the capacitors multimeter V 890D in capacitance measurement mode
Ceramic containers have a dielectric with greater resistance (ceramic, glass) so if you are checking the container the resistance must be greater than 2 MΩ. If the resistance is less, it is said about the failure of the tank. This means that charge drives of 0.25 μF and higher are checked. Capacitance below 0.25 μF Checking a conventional multimeter is not possible. LC meters are available for this purpose.
Although the function of measuring containers up to 200 μF can be found in some types of multimeters. Checking the capacitor with a multimeter without coming out of the circuit is also possible. At the same time it is necessary to observe the polarity during the transvelca and not to touch the probe by hand. The error of checking the capacities of the capacities installed on the board is higher, since the elements of the circuit affect the drive.
It is possible to check the capacity of the capacitance approximately and on the spark, that is, to charge the operating voltage of the container, and keep moving the metal screwdriver with an insulated handle of the outlet. According to the strength of the discharge, you can roughly judge the performance of the container. When checking the drive on the spark of 220 V networks for work on the network 220 V and above, it is necessary to take safety measures and discharge the capacity through a resistor 10 com.
Checking the capacitors in the arrow tester C 4353
The arrow tester is more convenient for checking the performance of drives. The tester arrow while measuring the container moves smoothly along the dial, which gives a correct test pattern than the flashing digits digital multimeter. The failure of the charge drives can also be determined visually on the compensation of the body, dark spots and foam holes on the element.
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