One bike goes: a multimeter is not needed to check a capacitor. The schoolchildren of the bad guys hurt the guys with a weaker extravagant method. Charged a large capacity outlet, beat with current. Check the performance of the main capacitor pulse power supply is not difficult. In a personal computer, the voltage reaches 650 volts, if you touch it, it will bounce. Avoid using a screwdriver. The temperature of the arc is so high that the desire to know the capacitance of the capacitor can turn into quite good practical skills of the welder. For the purpose of discharging, craftsmen use a cartridge equipped with an Ilyich lamp. The high reactive impedance of the helix makes it easy to solve the problem of how to check a capacitor with a multimeter.
The process of checking the capacitor
You will see, everyone can check the capacitor with a multimeter. Non-polar capacitor, ceramic capacitor, the differences give little, much determines the nominal. However, hybrid technology can bring surprises. It is clear, to remove the SMD capacitor is a serious matter( the majority can not afford it).Then perform indirect tests, for example, comparing readings with a known working device.
The simplest method for testing a capacitor is a field test. And as part of the original scheme. Take the trouble:
- Download the desired scheme on the Internet, there is hardly a ready in the hands.
- Measure the voltage across the capacitor under test. In power supplies, for example, it is convenient to walk on the tires of the ground-power, figuring out the question. It is decided not to check the capacitor directly, but to know the exact range set by the multimeter. The kind of current( voltage) is incorrect, the contacts are incorrectly connected - the output of the meter fails guaranteed.
- The task is to check the presence of voltage on the capacitor. There is - the capacity is charged.
- Circuit trace the path of the discharge: resistors, diodes, transistors, included in the right direction. Let's make a reservation, we are talking about large, powerful capacitors, mainly power supplies. Polarity prevents discharge through a rectifier diode connected in the opposite direction. An increase in the nominal resistor increases the process time; the element will start to beat with current. Scientists call the discharge time, a phenomenon characterized by a constant, representing the product of the nominal resistor and the capacitance, expressed by farads. Taking a tester, putting on a constant range, we see a falling potential. By time it is easy to estimate the value, suitability of the tank.
- multimeter. Having troubled to turn on the multimeter in the opposite direction, you will see not the discharge of a capacitor, but the failure of another brainchild of Chinese industry. Beginners need to know one thing: the contacts of the multimeter are signed, avoid neglecting the study of the appearance of the device.
- The black wire is zero( earth, neutral).Subscribe Com( English common), marked with a ground symbol.
- Opposite the other terminals there are limits. Here, in what is working, stick in there. A red wire is used for this, some multimeters refuse to work if the connection is incorrect.
So, the instructions for working with the tester will be needed, the color of the wires will show where to poke. It seems ridiculous until you try to measure the high voltage pulsed with a tiny microchip. Next to the lying body, wires, many other things will interfere. In such conditions, apply special finest probes, the set is devoid of accessories. We recommend to practice in advance with a multimeter to work. Be especially careful of the outside. Most modern testers have the following options for conducting work:
- Measuring AC voltage will be needed by most. The range is marked with a tilde ~.Nearby is the English letter V( Voltage).
- . Constant voltage is marked similarly, dashes and dots stand next to them. Like the equal sign, which has the bottom line cut in three smaller lines.
- Current is often measured constant. Be careful to avoid burning the device. Marked set of ranges with the letter A( Ampere).Unlike voltages, where thousands of volts appear, the multimeter offers to be content with a dozen. Less than the current charge of the car battery. PC processor consumes more total.
- It is useful to know the resistance ratings, this sort of radio elements can be more often extracted from the old circuit by supplying a new one. Clearly, it is impossible to make a mistake, or the magnitude of the error should be minimized. The scale of resistance is marked with the letter Ω( Omega) of the Greek alphabet. The professional environment marks the ohms in a peculiar way.
- The most necessary for most users will seem dial mode. You need to check the diodes, some transistors, much more often with the help of the option just evaluate the integrity of the wires. It is important here that the circuit is not energized. Otherwise the tester will burn. The mode is marked with a buzzer icon, or the conventional designation of a diode circuitry. The dial is called due to the characteristic feature: after passing a successful test, the multimeter will begin to squeak subtly.
- A separate topic of conversations is the test of transistors and diodes for operability using a special socket marking emitters, collectors, bases, and some other electrodes of radio radio elements.
Check the capacitance of the capacitor with a multimeter
It is easier to check the electrolytic capacitor with a multimeter. Start better with visual control. Faulty electrolytic capacitors swell noticeably. On foreign models, a special cross-shaped slot is made at the top of the cylinder to guarantee failure indication. External signs are silent - you need to grab a multimeter. First, the element is guaranteed to discharge. Usually there is no voltage, but poking a bare screwdriver, a piece of wire is a stupid idea. It’s nice to create a discharger with your own hands, using a cartridge screwed in by a light bulb. Gizmo is universally used by TV repair masters and switching power supplies. A few words about the process, when the capacitor is discharged, you can grab the tester.
On the contacts of the multimeter in some modes, the voltage goes 5 volts. Required to evaluate the parameters. For example, when measuring the resistance, the multimeter simply divides the voltage into current, gets the desired value. The first digit is known - 5 volts( determines the model of the tester).Similarly carried out dialing. Served 5 volts at both ends. Some zener diodes make their way. Ringing such items on digital multimeters is not possible.
Knowing these things, we understand what to do next:
- We connect in the mode of measuring the resistance of the terminal to the contacts of a discharged capacitor.
- A charging circuit is formed, formed by the internal resistance of the multimeter, capacitance. Initially, the current is infinite, then decreases, reaching zero.
- In passing, resistance will begin to grow from zero to infinity.
Any capacitor with an operating voltage higher than 5 volts will be checked in this way. A single focus can be thrown out by polar, for example, electrolytic capacitances. In parallel, we track the correctness of the location of the probes( red, black).Now we are analyzing. We found out whether the capacitor is suitable, some features are present. Discussed 5 volts on the multimeter probes, the value strongly depends on the model. We can measure at the ends of a known-good capacitor: while we call the contacts, the capacity will be charged to the desired value.
So, the voltage of the test sample is very different from the reference readings( you need to take care of the receipt in advance), it probably broke. We start to measure the voltage of the capacitor, the internal resistance of the device is inferior to infinity. The potential will begin to slowly fall, we note on the screen. We make two conclusions:
- The initial value of the voltage is much lower than the standard( the tester gives to the contacts, the dialing mode) - there is a leak inside. The parameter normally forms part of the Q formula, if the capacitor discharges quickly on its own( without intentionally closing the contacts), the element has served.
- By the discharge rate, you can estimate the size of the capacitor capacitance. You can, of course, be confused with the definition of constants, formulas, it is easier to conduct a test with knowingly working capacities, and then summarize the results with a table. It will be possible to judge the value of the capacitor by one discharge rate. The process resembles the assessment of pressure using a tonometer. Focus on the eye. The value of capacitance is determined by the speed of the voltage drop on the display of the multimeter.
Of course, more offhand is being done, it will be possible to distinguish between uF and MF without difficulty. For those who want more, we can tell you: during the RC charge drops by 63%.Everyone is free to calculate the volt level for a multimeter. Calculate the approximate internal resistance, based on the data obtained, to conduct an approximate measurement of the capacitor capacitance.
A simple way to check the capacitance of a capacitor with a multimeter is known. Buy a tester that has the appropriate scale. It is written with the letter F( Farad).Just takes the capacitor legs, approximately the range is set, the multimeter does the work described above. Check the capacitor with a multimeter without soldering is not always possible. In parallel, the capacitors included resistors, chokes, and other elements( including capacitors) that made it difficult to assess the serviceability. Whether electrolytic capacitor, film capacitor, any other. Of course, much will determine the specific denominations.
Make a comparison. For example, on a serviceable vehicle it shows a fixed value, on a broken one something else. Optionally a faulty capacitor with a multimeter on the board found - the discharge circuit junk. Auto Starting Capacitor - it is possible to remove, check( after having processed the spark gap), the technique is not always effective for electronics.