Ordinary multimeters can also play new tricks, use multimeter resistance files to judge whether the capacitors are good or bad.

Capacitors are simply two conductors that are close together, with a dielectric interposed between the conductors, which are the two plates of the capacitor. Depending on the material, capacitors are divided into many types, such as ceramic capacitors, polyester capacitors, electrolytic capacitors, tantalum capacitors, and polypropylene capacitors.

In this case, the pointer should be pointed between 1/3~2/3 of the scale.
b ohms zero. Before measuring the resistance, short the two test leads and adjust the “ohmic (electrical) zero adjustment knob” so that the pointer just points to the zero position to the right of the ohmic scale. If the pointer cannot be adjusted to zero, the battery voltage is insufficient or there is a problem inside the meter. And every time you change the multiplier, you must perform ohms zero again to ensure accurate measurement according to the principle of the capacitor. It is not difficult to understand that the two poles of the capacitor should be insulated and the resistance is infinite. The actual situation is not the same as the theory. For a general non-polar capacitor, the resistance can be considered to be infinite. But the resistance is infinite, and there is another case of open circuit (or open circuit), at which point the capacitor has lost its effect, that is, the broken capacitor.

Therefore, for the non-polar capacitors, the following experience is summarized. Use a multimeter X1K or X10K ohms to measure the capacitor. Before measuring, short the capacitor with a test lead and measure the capacitor resistance. When measuring, do not touch the two poles of the capacitor to prevent the influence of human body resistance interference, and watch the needle swing to the right. Generally, first swing to the right to a position, such as 200, and then slowly stop to the left infinity. Then change the hands and test again. The hands should be swung right to just twice the amplitude (such as 50), then stop to the left to infinity. The capacitor on the surface is good, and there is no failure, it is capacity.

For polar electrolytic capacitors, the method is basically the same as above, but the resistance is not infinite. Electrolytic capacitors generally have a large capacity, so the X100 or X1K files are often used, and the capacitors are short-circuited first to discharge the capacitors. The first measurement looks at the maximum amplitude of the right swing, and then exchanges the meter to measure again. The maximum amplitude of the right swing should be twice the first time. Finally, the test leads are parked close to infinity, so that the capacitor is basically determined to be effective. If the amplitude of the swing to the right is small or the amplitude of the swing is the same, the basic determination is bad.

The above is to measure capacitors with the most common multimeter, but now many people have upgraded and switched to digital multimeters. A slightly better multimeter has the function of measuring capacitors, not only can judge good or bad, but also can measure the capacity. However, it is good to know some of the above methods.