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When we don't know the positive and negative poles of the chip capacitor, we can use a multimeter to measure it.

Chip capacitor, also known as SMD capacitor, surface mounted capacitor, its appearance is usually yellow, black or Baby blue. It can be divided into two categories: non polarity and polarity. Now we mainly discuss the difference between positive and negative electrodes and polar chip capacitors.

In this way, we first assume a certain extreme "pole, pointer multimeter R * 100 or R * 1K block, and then assume" pole and the black probe of the multimeter, the other pole and the red probe of the multimeter, and write the scale of the needle stop.

Then discharge the capacitor (touch the two leads), adjust the two pens and re measure. In the two measurements, the last time the needle stopped on the left (or the resistance was high), the black pen was connected to the positive pole of the Electrolytic capacitor.

The positive and negative electrodes of the Aluminum electrolytic capacitor are different from the black block on the measuring capacitor, which is the negative electrode. There are two semicircles at the capacitance position of the PCB, and the colored semicircle corresponds to a negative electrode. The positive and negative long legs are distinguished by pointing and error, and the short leg corresponds to the negative electrode.

The dielectric between the capacitor poles is not an absolute insulator, and its resistance is not infinite, but a finite value, generally greater than 1000 MHz. The resistance between the two poles of a capacitor is called insulation resistance or leakage resistance.

Only when the positive pole of the Electrolytic capacitor is positive and the power supply of the negative terminal is negative, the red stylus of the barrier, the leakage current of the Electrolytic capacitor is small (the leakage resistance is large). On the contrary, the leakage current of Electrolytic capacitor increases (the leakage resistance decreases).