The effect of SMD inductance
1. SMD inductance is a magnetic induction element wound with insulated wire;An inductive element belonging to one of the commonly used passive components.
2, the role of SMD inductor: through dc resistance ac function, mainly to isolate the ac signal, and filter or with capacitors, resistors and other components of resonant circuit.Tuning and selective inductance.
3. The LC tuning circuit can be formed by parallel connection between the inductance coil and the capacitor. In the circuit, the power inductance plays the role of resonant tuning.
4. Any current in the circuit of SMD inductor is the circuit where the inductor is. The magnetic field will be generated, and the magnetic flux of the magnetic field ACTS on the circuit.At this time, the circuit is loaded with a certain magnetic flux.Usually in engineering;The more saturated the magnetic flux is;The more stable the inductance is in the circuit.
5. When the current through the SMT inductor changes, the dc voltage potential generated in the SMT inductor will prevent the current from changing.To keep the changing current out of this circuit;Because the changing current could be large;If the general circuit can not withstand the case;May impact other components in the circuit;It was the entire electric roadbed that burned out.
6, when the current through the patch power inductance increases, the inductance generated by the self-induction electromotive force and electricity when the current through the inductance decreases, the self-induction electromotive force and the current direction are the same, prevent the decrease of the current, while releasing stored energy, to compensate for the decrease of the current.The current flows in the opposite direction, preventing the current from increasing.
7. Convert some electric energy into magnetic field and store it in inductance;Therefore, after inductance filtering, not only the load current and voltage pulsation decreases, waveform becomes smooth, and the rectifier diode conduction Angle increases.
8. The power inductance of the SMT is different from that of the general SMD inductor. The general SMD inductor has a single function in the circuit.Play EMC at the same time;EMI has the function of power storage.
9, shield SMD inductor can shield out the instability of the current in some circuits, a good role in blocking, shield inductor complete metal shield will be surrounded by a positive conductor, in the inside of the shield body will be induced and live conductor equivalent negative charge.
10. The outer side has the same amount of positive charge as the charged conductor. If the metal shield is grounded, the positive charge on the outer side will flow into the earth, and there will be no electric field on the outer side.
SMD inductance identification method
Want to know SMD inductance recognition method, first understand the basic characteristics of SMD inductance.SMD inductors are characterized by miniaturization, high quality, high energy storage and low resistance.Adapt to the modern miniaturization of electronic products, and facilitate the mechanization of production, improve production efficiency so as to be widely used.
SMT inductor has many types, such as: laminated strips inductance, not wire wound, come out in the burn, ferrite laminated inductance mainly with ferrite material powder in the high temperature furnace to burn out, the inductance of the ceramic body, of course, is burned for ceramic materials, two different materials to make them have different frequency characteristics of the ceramic body has good performance in high frequency applications, not a ferrite, but the ceramic inductors are not very high, generally only in the level of nH, ferrite can be dozens of micro heng, of course, the greater the sense of volume, the greater the amount can be done.
It has good magnetic shielding, high sintering density and good mechanical strength.The disadvantages are low pass rate, high cost, small inductance and low Q value.
Compared with the winding inductor, it has many advantages: small size, conducive to the miniaturization of the circuit, magnetic circuit closed, will not interfere with the surrounding components, will not be disturbed by adjacent components, is conducive to the high-density installation of components;Integrated structure, high reliability;Good heat resistance and weldability;Regular shape, suitable for automatic surface installation production.
Winding SMT inductance: it is characterized by a wide range of inductance (milliheng ~ heng), high inductance accuracy, small loss (that is, Q), allows large current, manufacturing process inheritance, simple, low cost, but the shortage is in the further miniaturization is limited.The coil type inductor with ceramic core can maintain a stable inductance and a fairly high Q value at such a high frequency, so it occupies a place in the high frequency circuit.Wound SMT inductors can be typed on the body, such as 1 r0 refers to 1 microheng.
SMD power inductor: also a wound type power inductor, high current inductor.Surface mount high power inductance, with miniaturization, high quality, high energy storage and low resistance characteristics.SMT power inductance body can be typed such as 220 refers to 22 microsense.
SMD shielding inductance: the magnetic circuit is closed, which will not interfere with the surrounding components or the adjacent components, which is conducive to the high-density installation of components;Integrated structure, high reliability;Good heat resistance and weldability;Shape regular, suitable for automatic surface installation production, with miniaturization, high quality, support for large current, SMT shield inductor body can be typed such as 151 refers to 150 microsense.
SMD inductor reading, printed word is generally three, the first two is effective value, the last digit is times, the reading is effective value times times, such as: printed word 180 is effective value of 18, times is 10 to the 0 power is 1, then 180 is 18 times 1 is 18 micro heng;If 221 is valid for 22, times 10 to the 1 is 10, then 221 is 22 times 10 is 220 microheng.In addition to the commonly used in addition to a lot of SMT inductors are not listed one by one.
Post time: Oct-09-2019