Do you know the three functions of a capacitor?

Today's article combs through the three major roles of capacitance, energy storage, filtering, and coupling.

1. Energy storage

It is common for capacitors to store energy, usually in power supplies.

If the output of the power supply IC does not increase the large capacitor energy storage, when the IC needs to consume current, the previous power supply chip and the IC due to the distance, usually will not respond quickly, so that the voltage of the IC will drop, so that it can not work normally. Therefore, capacitor energy storage is added at the chip pin to provide energy to IC quickly, which can prevent voltage drop.

In practical applications, the output power of the power supply IC is 5V1A, and the power of the load is 5V0.55a when the load is working normally, but the maximum instantaneous power of the load is 5V2A, and the duration of ms level. If the power supply IC is used alone to provide energy to the load, then when the auxiliary instantaneous current needs 2A, it is obvious that the previous power supply cannot provide. At this point, we would connect multiple large capacitors to the front stage of the load to provide the load current of the rear stage at high power.

Step 2: Filter

The capacitor used for filtering is to make use of the characteristics that the capacitor voltage cannot change, and for high frequency signals, the impedance of the capacitor is low, so the noise signal on the signal line can be bypassed, so as to achieve the role of filtering.

Of course, when the capacitor is filtered, it is generally used with resistance or inductance to form a RC or LC filter circuit, so that the effect will be better.

3. Coupling

The basic characteristic of the capacitor is to separate the straight connection. When the AC signal with DC bias passes through the coupling capacitor, the DC bias cannot pass through the capacitor, resulting in the bias of the AC signal becoming 0.

Capacitors are often used in audio circuits for coupling purposes.

The normal operation of the MIC requires DC voltage, and the resistance of 15K is to ensure that the MIC can work normally to provide current. The coupling capacitor 22uF is added to the MIC to eliminate the DC signal in the AC signal output of the MIC, so that the AC signal can enter the amplifier to make full use of the characteristics of positive and negative power sources. If the signal is DC biased, then the signal is only half as dynamic.

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