In DC circuits, capacitors are equivalent to disconnection.Capacitors are a component that can store charge and one of the most commonly used electronic components. This has to start with the structure of the capacitor.The easiest capacitor is composed of the pole plates at both ends and the middle insulating medium (including air) in the middle.After the power is powered, the polar plate is charged, forming a voltage (Poor for the potential), but due to the insulated matter in the middle, the entire capacitor is non -conductive.However, this situation is that it does not exceed the critical voltage of the capacitor (breakdown voltage) Under the prerequisite.We know that any material is relatively insulating. When the voltage at both ends of the material increases to a certain degree, the material can be conducted. We call this voltage For a breakdown.The capacitance is no exception. After the capacitance is penetrated, it is not an insulator.However, in the middle school stage, such voltages are not seen in the circuit, so they are all penetrating the electricity Those who work below can be regarded as insulators.

However, in the AC circuit, the direction of the current becomes a certain functional relationship with the direction of the current.The process of filling the capacitor is time to charge. At this time, in the shape of the pole plate The changing electric field, and this electric field is also a function of changing over time.In fact, the current is passed by the capacitor through the form of a electric field.The role of capacitors:

● Coupling: The capacitance used in the coupling circuit is called a coupling capacitor, and this capacitance circuit is used in large quantities in blocking capacity coupling large and other capacitor coupling circuits. use.

● Filter: The capacitor used in the filter circuit is called a filter capacitor. This capacitor circuit is used in power filtering and various filter circuits. Remove in the total signal.

● Antuction: Capacity used in the degraded circuit is called a degenerate capacitor. This capacitor circuit is used in the DC voltage supply circuit of a multi -stage amplifier. The harmful low frequency intercourse.

● High -frequency vibration: Capacitors used in high -frequency vibration circuit are called high -frequency vibration capacitors. In the audio negative feedback amplifier, in order to eliminate high -frequency self -excitement, this kind of capacitance is used. Road to eliminate high -frequency howls that may appear in the amplifier.

● Residents: Capacitors used in the LC resonance circuit are called resonance capacitors. This capacitive circuit requires such capacitance circuits in LC parallel and series resonance circuits.

● Wingrser: The capacitors used in the bypass circuit are called bypass capacitors. If the circuit needs to remove the signal of a certain band from the signal, you can use the bypass capacitor circuit and remove it according to what you remove. The signal frequency is different, and there are all -frequency domain (all AC signals) bypass capacitor circuits and high -frequency bypass capacitor circuits.

● Neutralization: Capacitors used in neutral circuits are called neutralized capacitors.In the high -frequency and medium frequency amplifier, the TV high -frequency placing large device, this neutralized capacitor circuit is used to eliminate Self -exciting.

● Timing: Capacitors used in timing circuits are called timing capacitors.Use the timing capacitor circuit to use the circuit of time control through capacitor charging and discharge, when the capacitor is controlled The role of the constant size.

● Points: The capacitors used in the integral circuit are called integration capacitors.In the synchronous separation circuit scanned by the potential field, the use of this integral capacitor circuit is used to compound the synchronization signal from the field Take the synchronization signal.

● Micro -division: The capacitor used in the differential circuit is called a differential capacitor.In order to obtain a spire trigger signal in the trigger circuit, this micro -capacitance circuit is used to from various types (mainly Reinforcement pulse) The sharp top pulse trigger signal is obtained in the signal.

● Compensation: The capacitors used in compensation circuits are called compensation capacitors. In the bass compensation circuit of the card seat, use this low -frequency compensation capacitor circuit to enhance the low -frequency trust in the sound release signal No., in addition, there are high -frequency compensation capacitance circuits.

● Self -lifting: The capacitors used in the self -lifting circuit are called self -lifting capacitors. The commonly used OTL power amplifier output class circuit uses this self -lifting capacitor circuit to use a positive feedback method Increase the signal in half a week.

● Frequency division: The capacitors in the frequency division circuit are called frequency -dividing capacitors. In the speaker's speaker frequency division circuit, use frequency -frequency capacitor circuits, so that high -frequency speaker works The speaker works in the medium frequency band, and the low -frequency speaker works in the low frequency band.

● Load capacitance: refers to an effective external capacitor that determines the load resonance frequency with the quartz crystal resonator.The standard values commonly used in load capacitors include 16PF, 20PF, 30pf, 50PF and 50pf and 50pf 100pf.The load capacitance can be adjusted appropriately according to the specific situation. By adjusting, the operating frequency of the resonator can be adjusted to the nominal value.