Tell us about how capacitive inductors work

If a capacitor is connected to direct current, it is charged at the moment it is turned on. Because Q = Cu, there is an instantaneous directional movement of the charge in the circuit, and there is a brief current. But once stabilized, the charge in the circuit no longer moves, and therefore there is no current in the circuit.

The capacitor is discharged when there is a change in the circuit that causes the voltage across the capacitor to decrease. Because q= cuAfter stabilization, there is no current in the current.

Because the voltage of the alternating current is constantly changing, the capacitor is constantly charging and discharging. So the current seems to pass through the capacitor, but not through the capacitor.

Of course, capacitors also have a hindrance effect on alternating current.

The inductor is an energy storage element, and the inductor is mostly used in the power filter loop, focusing on suppressing conductive interference; Magnetic beads are mostly used in signal loops, mainly in EMI. Inductive components and EMI filter components are used in a large number of PCB circuits of electronic devices. These components include chip inductors and chip beads, and the characteristics of these two devices are described below and their general and special applications are analyzed.

The benefits of surface-mount components are the small package size and the ability to meet physical space requirements. With the exception of differences in impedance values, current-carrying capacity, and other similar physical properties, the other performance characteristics of through-hole connectors and surface-mount devices are essentially the same. In the case of chip inductors, the inductors are required to perform the following two basic functions:

Circuit resonance and choke reactance. Resonant circuits include resonant generation circuits, oscillation circuits, clock circuits, pulse circuits, waveform generation circuits, and so on. The resonant circuit also includes a high-Q bandpass filter circuit.

For a circuit to resonate, both capacitance and inductance must be present in the circuit. There is parasitic capacitance at both ends of the inductor, which is due to the fact that the ferrite body between the two electrodes of the device acts as a capacitive medium. In the resonant circuit, the inductor must have a high q, narrow inductance deviation, and stable temperature coefficient in order to meet the requirements of narrow band and low frequency temperature drift of the resonant circuit.

High-q circuits have sharp resonant peaks. The narrow inductor bias ensures that the resonant frequency deviation is kept to a minimum. The stable temperature coefficient ensures that the resonant frequency has stable temperature change characteristics.

The difference between standard radial and axial inductors and chip inductors is simply the package. Inductive structures include coils wound over dielectric materials (usually alumina ceramic materials) or air-wound coils and ferromagnetic materials. In power applications, when used as a choke, the main parameters of the inductor are DC resistance (DCR), current rating, and low Q value.

When used as a filter, a wide bandwidth characteristic is desired, so the high q characteristic of the inductor is not required. A low DCR guarantees minimal voltage drop, defined as the DC resistance of a component in the absence of an AC signal.

In layman's terms, they are all energy storage elements. The energy that converts electrical energy into a magnetic field.

It is recommended to find a book and read it.

Capacitor operating characteristics: Capacitance (or capacitance) is a physical quantity that expresses the ability of a capacitor to hold charge. Capacitance from the physical point of view, it is a static charge storage medium, may be permanent charge, this is its characteristic, it is widely used, it is an indispensable electronic component in the field of electronics and electricity.

It is mainly used in power supply filtering, signal filtering, signal coupling, resonance, filtering, compensation, charge and discharge, energy storage, DC isolation and other circuits.

A bypass capacitor is an energy storage device that provides energy to the local device, which can uniformize the output of the stable parallel or voltage device and reduce the load demand. Like a small rechargeable battery, a bypass capacitor can be charged and discharged into the device. To minimize impedance, the bypass capacitor should be as close as possible to the power supply and ground pins of the load device.

This is a good way to prevent ground potential elevation and noise caused by too large input values. The ground potential is the voltage drop at the ground junction when it passes through a high-current burr.

Inductor working characteristics: Inductive appliances have a certain inductance, which only hinders the change of current. If the inductor is in a state where no current is passing through it, it will try to block the flow of current through it when the circuit is turned on; If the inductor is in a state where current is passing through it, it will try to maintain the current when the circuit is disconnected.

Inductors are also known as chokes, reactors, and dynamic reactors.

The characteristics of an inductor are the opposite of those of a capacitor, and it has the characteristic of preventing the passing of alternating current and allowing direct current to pass through. The resistance of the DC signal when passing through the coil is the resistance of the wire itself, and the voltage drop is very small; When the AC signal passes through the coil, the two ends of the coil will produce self-induced electromotive force, and the direction of the self-induced electromotive force is opposite to the direction of the applied voltage, which hinders the passage of AC, so the characteristics of the inductor are DC and AC resistance, the higher the frequency, the greater the coil impedance. Inductors often work together with capacitors in circuits to form LC filters, LC oscillators, etc.

In addition, the characteristics of inductors are used to create chokes, transformers, relays, and so on.

Resistance is a component that has a certain blocking effect on AC and DC current, and plays a role in step-down, voltage division and cross-linking in the circuit, capacitance is a capacitive element composed of two mutually insulated plates, which plays an insulating role in DC, and plays a different amount of conduction role with the size of the capacitive reactance to AC, mainly used for the circuit of blocking the AC and bypassing, the inductance is composed of coils with different turns, and it is also a pure resistance for DC, and its inductance is related to frequency for AC, the higher the frequency, the more difficult it is to pass through it, The three of them together can form various oscillation circuits, positive feedback negative feedback and other circuits.

In addition to resistors, capacitors are the second most commonly used component. The main physical characteristic of a capacitor is the storage of electrical charge. Since the storage of electric charge means the storage of energy, it can also be said that the capacitor is an energy storage element, or more precisely, the storage of electrical energy.

Two parallel metal plates form a capacitor. There are also many kinds of capacitors, it includes fixed capacitors, variable capacitors, electrolytic capacitors, ceramic capacitors, mica capacitors, polyester capacitors, tantalum capacitors, etc., among which tantalum capacitors are particularly stable. Capacitors are divided into fixed capacitors and variable capacitors.

Fixed capacitors are often used in circuits for coupling, filtering, integration, and differentiation, and together with resistors to form RC charge-discharge circuits, and with inductors to form LC oscillation circuits, etc. Since the capacitance of a variable capacitor can be arbitrarily changed within a certain range, when it forms an LC loop together with the inductor, the resonant frequency of the loop changes with the change of the capacitance of the variable capacitor. The general receiver circuit uses such a principle to change the receiving frequency of the receiver.

The inductor is made of coils, and its role is mostly to choke and filter out high-frequency clutter, and it has many shapes: some like resistors, some like diodes, and some look like coils. Usually only inductors like resistors can read the inductance value, because only this colored ring is the only one that has nothing else.

The shape of the chip inductor is the same as that of the digital identification chip resistor, except that it does not have a number and is replaced by a small circle. Since the number of inductors used is not too much, everyone just needs to understand it. In addition, in a certain sense, all kinds of transformers are actually composed of inductors.

The magnitude of the inductance coil's effect on the AC current obstruction is called the inductive reactance XL, and the unit is ohms. It is related to the inductance l and the alternating current frequency f as XL=2 FL

Inductance coils. The inductance coil is made of wires wound around the insulating tube one by one, and the wires are insulated from each other, and the insulating tube can be hollow, or it can contain an iron core or a magnetic powder core, referred to as inductance. Expressed in L, the units are Henry (H), MilliHenry (MH), Micro Henry (UH), 1H=10 3MH=10 6UH.

1. Classification of inductance.

Classified by inductance form: fixed inductance, variable inductance.

Classified according to the nature of the conductor: air core coil, ferrite coil, iron core coil, copper core coil.

Classified by the nature of work: antenna coil, oscillation coil, choke coil, notch coil, deflection coil.

Classified by winding structure: single-layer coil, multi-layer coil, honeycomb coil.

A capacitor series can block a low-frequency signal, an inductive series can block a high-frequency signal, and the opposite is true. Of course, there are many other functions, such as electrolytic capacitive filtering.

Inductance: DC, AC.

Capacitance: AC, DC.