In a DC circuit, the capacitor is equivalent to an open circuit. A capacitor is an element capable of storing charge, and is also one of the most commonly used electronic components.
This must start from the structure of the capacitor. The simplest capacitor is composed of polar plates at both ends and an insulating dielectric (including air) in the middle. After being energized, the plates are charged, forming a voltage (potential difference), but due to the insulating material in the middle, the entire capacitor is non-conductive. However, this situation is under the premise that the critical voltage (breakdown voltage) of the capacitor is not exceeded. We know that any substance is relatively insulated. When the voltage across the substance increases to a certain level, the substance can be conductive. We call this voltage the breakdown voltage. Capacitors are no exception. After a capacitor is broken down, it is no longer an insulator. However, in the middle school, such voltages are not seen in the circuit, so they work below the breakdown voltage and can be regarded as insulators.
However, in AC circuits, the direction of the current changes as a function of time. The process of charging and discharging the capacitor has time. At this time, a changing electric field is formed between the plates, and this electric field is also a function of changing with time. In fact, current flows between capacitors in the form of an electric field.
The role of capacitors:
● Coupling: The capacitor used in the coupling circuit is called the coupling capacitor. This type of capacitive circuit is widely used in the resistance-capacitance coupling amplifier and other capacitive coupling circuits to play the role of blocking DC and AC.
● Filter: The capacitor used in the filter circuit is called the filter capacitor. This capacitor circuit is used in the power supply filter and various filter circuits. The filter capacitor removes the signal in a certain frequency band from the total signal.
● Decoupling: The capacitor used in the decoupling circuit is called the decoupling capacitor. This capacitor circuit is used in the DC voltage supply circuit of the multi-stage amplifier. The decoupling capacitor eliminates the harmful low-frequency cross-connection between each stage of the amplifier.
● High frequency vibration elimination: the capacitor used in the high frequency vibration elimination circuit is called the high frequency vibration elimination capacitor. In the audio negative feedback amplifier, in order to eliminate the high frequency self-excitation that may occur, this capacitor circuit is used to eliminate High frequency howling that may occur in the amplifier.
This must start from the structure of the capacitor. The simplest capacitor is composed of polar plates at both ends and an insulating dielectric (including air) in the middle. After being energized, the plates are charged, forming a voltage (potential difference), but due to the insulating material in the middle, the entire capacitor is non-conductive. However, this situation is under the premise that the critical voltage (breakdown voltage) of the capacitor is not exceeded. We know that any substance is relatively insulated. When the voltage across the substance increases to a certain level, the substance can be conductive. We call this voltage the breakdown voltage. Capacitors are no exception. After a capacitor is broken down, it is no longer an insulator. However, in the middle school, such voltages are not seen in the circuit, so they work below the breakdown voltage and can be regarded as insulators.
However, in AC circuits, the direction of the current changes as a function of time. The process of charging and discharging the capacitor has time. At this time, a changing electric field is formed between the plates, and this electric field is also a function of changing with time. In fact, current flows between capacitors in the form of an electric field.
The role of capacitors:
● Coupling: The capacitor used in the coupling circuit is called the coupling capacitor. This type of capacitive circuit is widely used in the resistance-capacitance coupling amplifier and other capacitive coupling circuits to play the role of blocking DC and AC.
● Filter: The capacitor used in the filter circuit is called the filter capacitor. This capacitor circuit is used in the power supply filter and various filter circuits. The filter capacitor removes the signal in a certain frequency band from the total signal.
● Decoupling: The capacitor used in the decoupling circuit is called the decoupling capacitor. This capacitor circuit is used in the DC voltage supply circuit of the multi-stage amplifier. The decoupling capacitor eliminates the harmful low-frequency cross-connection between each stage of the amplifier.
● High frequency vibration elimination: the capacitor used in the high frequency vibration elimination circuit is called the high frequency vibration elimination capacitor. In the audio negative feedback amplifier, in order to eliminate the high frequency self-excitation that may occur, this capacitor circuit is used to eliminate High frequency howling that may occur in the amplifier.
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