chip capacitors can be divided into two types: non polarity and polarity. the main function of chip capacitors is to eliminate the crosstalk of various high-frequency signals generated by the chip itself to other chips, so that each chip module can work normally without interference.
in high frequency electronic oscillation circuit, chip capacitor and crystal oscillator are used to form oscillation circuit to provide clock frequency for various circuits.
chip capacitors include ceramic chip capacitors, tantalum capacitors and aluminum electrolytic capacitors. the function of chip capacitor on the circuit board and the method to distinguish the polarity. the non-polar capacity of chip ceramic capacitor is also very small (pf level). it can withstand high temperature and voltage, and is often used in high-frequency filtering.
tantalum chip capacitors are characterized by long service life, high temperature resistance, high accuracy, excellent high frequency and wave changing performance. however, the capacity is smaller, the price is higher than that of aluminum capacitors, and the voltage and current resistance capacity is relatively weak, so it is used in low-frequency filter circuits with small capacity.
the capacity of chip type aluminum electrolytic capacitor is larger than that of tantalum chip capacitor. it is often found on the display card, and the capacity is between 300 μ f and 1500 μ f. it is mainly used to filter and stabilize the current at low frequency.
the black block marked on the capacitor is the negative pole. on the pcb, there are two semicircles on the capacitor position, and the pin corresponding to the colored semicircle is the negative pole. also useful pin length to distinguish between positive and negative, long pin is positive, short pin is negative.
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 connected to the positive power supply (the black probe when the resistance is blocked) and the negative terminal is connected to the negative power supply (the red probe when the resistance is blocked), the leakage current of the electrolytic capacitor is small (the leakage resistance is large).
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