What is the use of inductors and how to distinguish

First, choke: used to block low-frequency alternating current in low-frequency circuits; Pulsating direct current to pure direct current circuit; It is commonly used in the middle of two filter capacitors at the output end of the rectifier circuit, and the choke and capacitor form a Π filter circuit. In the high frequency circuit: is to prevent the high frequency current flow to the low frequency end, in the old regenerative radio high frequency choke; Be applied.

Second, filtering: the same as the above theory; It is also to prevent the pulsating DC current after rectification from flowing to the pure direct current routing choke (in order to simplify the circuit and reduce the cost, with pure resistance instead of the choke) two capacitors (electrolytic capacitors) composed of PI filter circuit. Pure DC is obtained by using capacitor charge-discharge and choke coil to smooth DC and block AC.

Third, shock: we say that rectification is to turn alternating current into direct current, then the shock is the reverse process of turning direct current into alternating current. We call the circuit that does this a "shaker." Shaker waveform: positive wave, sawtooth wave, trapezoid wave, square wave, rectangular wave, peak wave. The frequency is from several HZ-tens of GHZ. It is widely used in the field of cable power and radio.

In a circuit, when a current flows through a conductor, an electromagnetic field is generated, and the size of the electromagnetic field divided by the size of the current is the inductance

The definition of inductance is L=phi/i in Weber

Inductance is a physical quantity that measures the ability of a coil to generate electromagnetic induction. When a current is applied to a coil, a magnetic field is generated around the coil, and magnetic flux passes through the coil. The larger the power supply into the coil, the stronger the magnetic field, and the greater the magnetic flux through the coil. Experiments show that the magnetic flux through the coil and the current through is proportional, their ratio is called self-inductance coefficient, also known as inductance. If the magnetic flux through the coil is represented by φ, the current is represented by I, and the inductance is represented by L, then
L = φ / I

The unit of inductance is hen (H), and millihen (mH) or micro hen (uH) are also commonly used as units. 1H=1000mH, 1H=1000000uH.

Inductance can only work on unstable current, and its characteristics are that the voltage at both ends is proportional to the instantaneous rate of change (derivative) of the current passing through it, and the proportional coefficient is its "self-inductance".

The reason why inductance works is that it generates a changing magnetic field when passing an unstable current, and this magnetic field will in turn affect the current, so in this way, any conductor, as long as it passes an unstable current, will produce a changing magnetic field, which will in turn affect the current, so any conductor will have a self-inductance phenomenon

On the motherboard you can see a lot of copper wire winding coil, this coil is called inductance, inductance is mainly divided into two kinds of magnetic core inductance and hollow inductance, magnetic core inductance is often used in filter circuit, hollow inductance is small, often used in high-frequency circuit. The characteristics of the inductor are the opposite of the characteristics of the capacitor, which has the property of preventing the passage of the alternating current and allowing the direct current to pass smoothly. The characteristics of the inductor are DC and AC, and the higher the frequency, the greater the coil impedance. Inductors often work with capacitors in circuits to form LC filters, LC oscillators, etc. In addition, people also make use of the characteristics of inductance to manufacture choke coils, transformers, relays and so on.

Types of inductors

According to the shape, inductors can be divided into hollow inductors (hollow coil) and solid inductors (solid coil). According to the working nature, inductors can be divided into high-frequency inductors (various antenna coils, oscillating coils) and low-frequency inductors (various chokes, filter coils, etc.). According to the package form, inductors can be divided into ordinary inductors, color ring inductors, epoxy inductors, chip inductors and so on. According to the amount of inductance, inductors can be divided into fixed inductors and adjustable inductors.

The role of inductance: through DC, AC

Through DC: The so-called through DC means that in the direct current circuit, the role of the inductor is equivalent to a wire, without any effect.

Ac resistance: In an AC circuit, the inductor will have an impedance, that is, XL, and the current of the entire circuit will become smaller, which has a certain hindering effect on AC.