Such a detail as a capacitor is familiar to many radio amateurs. It is found in almost any electrical appliance, and most of the malfunctions are associated with its failure. Those who are fond of this line of activity will be interested to know how to ring a capacitor. Any home radio amateur will have a wide range of different parts, including the items in question.
And since most of them have already been used, which is dictated by efficiency, it is necessary to check their performance. But first, a little theory as to what these necessary elements are, on what principle they work, and what is their scope.
What is a capacitor?
A capacitor is a part that is present in almost every electrical circuit. Among all equipment breakdowns, almost a little more than 50% are associated with a malfunction of this radio element.
The design of the capacitor is notdiffers in complexity. Two metal plates are separated by a dielectric. In classic products, different materials were used in its quality:
- air;
- paper (electrocardboard);
- ceramics;
- plastic.
Modern capacitors look a little different. In order to optimize the characteristics and their dimensions, thin foil (rolls) is used instead of plates, the sheets of which are separated by a dielectric. Is it possible to ring the capacitor in this case? Of course, yes, there are no "contraindications" here. Increasing the size of the plates allows you to increase their area. At the same time, the dimensions are not very large. However, performance suffers for the same reason.
Varieties of radio components
All capacitors are divided into two types:
- polar (electrolytic);
- non-polar.
The second parts are unpretentious in terms of operation. Only they are not able to accumulate a large capacity with a compact size. Polar capacitors are considered more progressive, but at the same time they have some disadvantages.
In the gap between the foil sheets, together with the dielectric inside the capacitor, there is an alkaline electrolyte. Based on this, such parts received a different name - electrolytic. They are given out by a cylindrical shape, contacts (positive and negative) are marked on their body, which is very important in the course of solving the question of how to ring the capacitor.
Despite the simpledevice, radio components are quite sensitive to electricity. In this regard, it is necessary to work with them very carefully. The same applies to checking electrolytic capacitors. That is, first you need to determine the polarity of the contacts, and then carry out diagnostics. If the radio component is connected incorrectly, it may become hot and burst.
How radio components work
How do capacitors work? In fact, their principle of operation is also easy to understand - they accumulate an electric charge. And because of this, such parts are mainly used in circuits where alternating voltage circulates. But this does not negate the use of capacitors on DC boards. Only here they will act as a dielectric, since they will not accumulate charge.
Main characteristics of capacitors
Before you figure out how to ring a capacitor, you need a little theory. Any such radio component has three important parameters:
- Capacity.
- Rated voltage.
- Breakdown current.
Of all three, it is the capacitance that characterizes the accumulation of electricity. The unit of measurement is Farad.
In almost all modern household electrical appliances, capacitors do not need a large capacity. Therefore, it is mainly measured in small fractions:
- millifarad – 10−3 F mF or mF;
- microfarad - 10−6 F uF or µF;
- picofarad –10−12 F pF or pF.
As the capacitance of the capacitor increases, its dimensions also become larger.
As for the rated voltage, this characteristic determines the value at which the capacitance will be equal to the parameter specified by the manufacturer. Of course, the maximum allowable value is indicated. Nevertheless, in the course of working with parts, it is necessary to select them with a margin. This will prevent parts from failing in the event of sudden power surges.
Breakdown is also of great importance in solving the problem of how to ring a capacitor with a multimeter, since it has a direct impact on the performance of the capacitor. No matter how well the radio component is made, when a certain voltage occurs, a breakthrough of current through the dielectric is not ruled out.
In other words, there will be a short circuit between the plates. And besides the fact that the capacitor itself will deteriorate, the entire electrical circuit is at risk. Sometimes parts can catch fire, which is common with film capacitors.
Where capacitors are used
Depending on the capacitance, capacitors can be used in different circuits of electrical appliances. Often they are successfully used for noise filters or power surges. As a rule, these are small-capacity radio components, more capacious elements are relevant for the production of low-power uninterruptible power supplies.
In the automotive industry, too, there is a place for capacitors. With their help,flickering turn signals on the car. Often here you have to ring the starting capacitor for serviceability.
But besides this, due to the ability to accumulate an electric charge, they are good where it is necessary to start up the maximum current for a short period of time. And here all those who thought about the flash will be right. That is, at first the charge accumulates for some time, and then all the electricity is instantly spent on lighting a powerful lamp.
But capacitors are widely used in the manufacture of devices that convert alternating current to direct current, where it smooths out ripples. By the way, if it is necessary to repair the power supply, the question arises in relation to checking the capacitors.
High-capacity radio components have been successfully used as starting elements for electric motors with a single-phase connection.
Main malfunctions
How to ring a capacitor with a tester? If any circuit does not work or the electric motor does not start, therefore, some element is inoperative (or there are several of them). With regard to capacitors, the following failures are typical failures:
- short circuit of the plates (breakdown);
- due to a break in the internal circuit of the part;
- exceeding leakage current;
- damage to the hull, due to which its tightness was broken;
- Lower capacity due to drying out.
These malfunctions appear for several reasons. Often this is an excess during operation of several parameters: temperature, voltage rating. Same heremechanical damage to the hulls can also be attributed.
Therefore, it is recommended to observe a lower temperature regime, which can significantly extend the life of many radio components, including capacitors, since it is precisely because of overheating that many elements fail.
Verification methods
How to ring a capacitor in an air conditioner or in any other electrical appliance? For this, a multimeter is most often used, but it is worthwhile to start with a visual diagnosis. In this case, a violation of the tightness of the case can serve as characteristic signs - it breaks, and the electrolyte flows out.
As a rule, radio components have the correct cylindrical shape. All detected bulges will indicate a breakdown of the capacitor. It is worth noting that defective radio components are only disposed of, as they cannot be restored.
If the body of the part is intact, then it is impossible to visually determine the malfunction due to an internal short circuit. In this case, you can not do without a multimeter. With the help of such devices, it is possible to carry out diagnostics of radio components in the range of 20 nF - 200 μF. And that's enough.
Checking non-polar parts
It is often quite difficult to ring a capacitor without soldering. Before testing capacitors of any type, it is advisable to disconnect them from the circuit. Diagnostics is carried out by measuring the resistance. The whole procedure is as follows:
- The capacitor needs to be discharged and for this it is worth closing bothoutput by touching a screwdriver (both at once) or any other metal object.
- The instrument turns on the ohmmeter mode and selects the maximum range.
- Both probes should touch the capacitor contacts (polarity does not matter in this case).
- If the unit is visible on the display, then this indicates the he alth of the part (the resistance value is more than 2 megaohm).
The probes themselves must be held only by isolated places, otherwise the readings will be unreliable. In this case, the resistance of your body will be measured.
For reliability, you can switch the device to diode mode, and if it beeps, this indicates a breakdown.
Checking polar capacitors
As a rule, the capacitance of non-polar capacitors is not more than 1 uF, while for electrolytic radio components, the range for this parameter is 0.5-1000 uF, or even more. Therefore, it is necessary to select 100 kOhm on the device. The rest of the check is exactly the same.
Before ringing the capacitor, it should also be discharged, and how to do this is described a little higher. If this is a high-voltage part, then it is better to use an ordinary incandescent lamp for this. If you ignore the discharge, then the capacitor can simply ruin the multimeter. In addition, "de-energizing" the part, touching it, you will get very unpleasant sensations.
A characteristic sign of the performance of electrolytic capacitors will be sparking when it is discharged. ATIn principle, the diagnosis can be stopped at this point. But it is better to bring the matter to the end - for reliability and reassurance.
Here, to check the radio component, it is necessary to observe the polarity (that is, the plus of the probe to the plus of the output and the same with respect to the minus). The DC current coming from the multimeter will accumulate in the capacitor, while the display shows an increase in resistance, which is normal.
With an analog instrument, you can perform a more visual check: the speed of the arrow deflection indicates the capacity of the part. The longer this happens, the greater it is.
Checking a part without soldering it
As mentioned above, it is desirable to remove the capacitors from the circuit, but this is not always possible when, for example, there are a lot of them. Then the problem arises of how to ring the capacitor on the board. With such diagnostics, it is necessary to include in the circuit the same element as the part being tested. The denomination must also be identical.
Only this technique can give the desired result only if the circuit uses a small voltage. Otherwise, when dealing with a large current, this method is highly discouraged.
