How to check the capacitor

Condensers are widely and versatile used in modern technology, primarily in electronics. Radio-technical and television equipment, radiolocation, telephony and telegraphy, automation and telemechanics, computing devices and electrical measuring instruments, laser technology - this is not a complete list of areas of their application. They are used practically by all branches of the national economy.

It is understandable that such a wide application of capacitors determines the diversity of their types. Along with miniaturized capacitors, there are real giants weighing several tons. Their capacity can range from a fraction of the picofarad to hundreds of thousands of microfarads, and the working nominal voltage can be in the range of several volts to many hundreds of kilovolts.

In our time in every home there are all kinds of household appliances, and, consequently, capacitors. Unfortunately, they often fail for various reasons, so the question is how to check the capacitor with a multimeter, tester or ohmmeter.

In practice, testing for breakdown and partial loss of capacity is often required. The reason for the breakdown is associated with a significant excess of the permissible operating voltage. Usually external signs of breakdown can be seen on the body of the element - spots, bloating, cracks, etc.

How to test a capacitor with a multimeter

For an electrical check, a multi-meter is useful. Before checking the capacitor, it must be discharged. It is especially important to observe this, starting to check the polar capacitor, which is characterized by high capacitance and high operating voltage. Ignoring this rule will damage the measuring device. To discharge a low-voltage capacitor, it is sufficient to short-circuit its terminals, and to discharge a high-voltage capacitor, this must be done through a resistor with a resistance of up to 10 ohms to avoid a spark. At the same time, it is impossible to touch the terminals by hand, otherwise an unpleasant electric shock is ensured.

It is important to know exactly how to check the capacitor in one or another situation, because the methods of verification depend on many factors.

The easiest way is to perform a test with a multimeter that has a capacitance measurement function, however, you should not forget about the need to observe polarity rules when working with polar capacitors.

Check the capacitors with a multimeter that does not have a special function, you can in the resistance measurement mode. Switching the multimeter to this mode, you need to touch the probes of the capacitor leads and, after waiting a couple of seconds, check the instrument's readings. If an infinitely large resistance value appears on the device - the capacitor is working, if the zero one is out of order. If the number on the display shows some intermediate value, the capacitor has a leak and loses part of the charge.

Thus, a multimeter without a capacitance check function can only determine the qualitative characteristics of the capacitor, but at least it makes it possible to draw conclusions about the need to replace it.

However, this test leaves the following question unanswered - how to test the capacitor for breaking the circuit. Damage of this kind can occur if the integrity of the dielectric inside the element is partially or completely impaired. Such a capacitor also shows infinite resistance, but it is impossible to rely on this indicator as a proof of its usability.

Knowing how to test the capacitor with a tester, you can also determine whether its capacitance corresponds to the specified tolerance limits. Knowledge of the real capacity is necessary for making a decision about its replacement or further use.