●INDUCTOR inductance

    A passive component, which acts to suppress changes in current. Inductance is often called "AC resistance". Its function of suppressing current changes and the ability to store energy in a magnetic field are the most useful characteristics of inductors; current flows through the inductor. The magnetic field, and the change of the magnetic field will induce a voltage in the opposite direction of the current generated. This characteristic of suppressing the current change is called the inductance value. The induced voltage at both ends of the inductor due to the current change can be defined as:

        V=L di/dt

    In this way, the induced voltage is proportional to the inductance value and the current change speed.

●INDUCTANCE inductance value

    The characteristic performance of the inductor, the inductance value determines the ability of the inductor to suppress current changes in the circuit. The inductance value depends on the material of the magnet, the diameter of the conductor, the number of turns and the shape of the coil. The international unit of inductance value is Henry (H), usually marked as microhenry (μH), and the conversion between units is as follows:

1H=103mH=106μH=109nH

●Nominal method of inductance value

    Usually the inductance value code is represented by three digits, the first two digits represent the effective digits of the nominal inductance value, and the third digit represents the number of 0 (magnification); if the third digit is 0, don’t write it; it is 1, Add a 0,; and so on, "R" represents the decimal point, and the unit of the nominal inductance value is μH. For example: R47=0.47μH 4R7=4.7μH 100=10μH 101=10*101=100μH etc.

●TOLERANCE tolerance

    Tolerance means that the measured inductance value of the inductor is allowed to float within the positive or negative tolerance of the nominal inductance value, and is usually represented by a specific letter. For example: J (±5%), K (±10%), L (±15%), M (±20%), N (±30%), etc. The smaller the value, the more stable the inductance value of the product. The better the consistency.

●DCR (Direct Current Resistance) DC resistance

      The resistance of the inductor coil measured under non-AC current. In the inductor design, the DC resistance is as small as possible. Its international unit is ohm (Ω), but in practical applications, only milliohms (mΩ) is usually used. , The DCR of the inductor is marked with the maximum value.

●Q (Quality Factor) quality factor

    Quality factor: Under the action of a sine wave, the ratio of the energy stored by the inductor in a cycle to the energy loss, it is an indicator of the relative energy loss of the inductor, also known as the "quality factor"; it is the inductive reactance (XL ) And the effective resistance (Re) ratio, as shown below:

    Since both inductive reactance and effective resistance are related to frequency, when determining the quality factor, you need to specify a frequency; at low frequencies, the increase rate of inductive reactance with frequency is greater than the effective resistance, but it also drops faster at high frequencies. The relationship between quality factor and frequency forms a bell-shaped curve; effective resistance is mainly produced by winding DC resistance, iron loss and surface effects. It can be seen from the above formula that the quality factor is zero at the resonance frequency, so the inductance value at this time is zero.

●DISTRIBUTED CAPACITANCE distributed capacitance value

    In the structure of the inductor, each winding or conductor acts like a capacitor plate, and the combined effect of each turn is like a single capacitance value, called a distributed capacitance value. This capacitance is connected in parallel with the inductor. The combination makes the inductor resonate at a certain frequency, called self-resonant frequency (SRF). Under a certain inductance value, a lower distributed capacitance value will have a higher self-resonance, and vice versa. The existence of distributed capacitance will affect the inductance performance of inductance products to a certain extent, so when designing, it is necessary to minimize the influence of distributed capacitance.

    The temperature range where components can be stored safely and without failure.

●OPERATING TEMPERATURE RANGE operating temperature range

    Refers to the ambient temperature range where the component can operate safely. The operating temperature is different from the storage temperature. The operating temperature needs to include the self-temperature rise generated by the DC bias current in the calculation. This energy loss is "copper loss". Power Loss=I2 (DCR)

    This value is higher than the ambient temperature due to the increase of the component temperature due to energy loss. Therefore, the maximum operating temperature will be less than the maximum storage temperature. The maximum operating temperature = storage temperature-self temperature rise.

●CURIE TEMPERATURE Curie temperature

    At this temperature or above, the ferrite core loses its magnetic properties. The magnetic permeability of the iron core generally rises rapidly when it is close to the Curie temperature, and the inductance value also rises. At the Curie temperature, the magnetic permeability drops to approximately one. The inductance value drops rapidly.

    For all magnetic materials, it is not magnetic at any temperature. Generally, magnetic materials have a critical temperature Tc. Above this temperature, due to the intense thermal motion of atoms at high temperatures, the arrangement of the atomic magnetic moments is chaotic. Below this temperature, the atomic magnetic moments are aligned, spontaneous magnetization occurs, and the object becomes ferromagnetic.

●COPPER LOSS copper loss

    The energy loss produced by the current flowing through the coil is equal to the square of the current multiplied by the resistance of the coil (I2R). These energy losses are converted into heat.

●CORE LOSS iron loss

    The iron loss is caused by the changing magnetic field in the iron core. This loss is related to the operating frequency and the total flowing magnetic flux. The total iron loss consists of three components, hysteresis loss, eddy current loss and residual loss. These losses are due to magnetic materials. Different, such as switching adjustment and RF design at high power and high frequency, you need to carefully select the core type to reduce the core loss and make the inductor perform best.

●CLOSED MAGNETIC PAHT closed magnetic circuit

    A magnetic core shape that can completely contain all the magnetic flux generated by the winding inductance can be regarded as an inductor with shielding, but the shielding is only different in degree.

●COMMON-MODE MOISE common mode noise

    Noise or electrical interference occurring on circuits related to grounding.

●SKIN EFFECT surface effect

    Surface effect (skin effect) refers to the tendency of alternating current to be conducted on the surface of the conductor rather than flowing through the entire cross section of the conductor. This phenomenon will increase the resistance of the conductor. The magnetic field related to the current in the conductor is in the center of the conductor. The eddy current is generated in the part which hinders the main current in the central part. When the frequency of the alternating current increases, the flow of the main current will be further pushed to the conductor surface. Usually, twisted wire can be used to reduce its impact on product performance.

●FILTER filter

    Refers to a circuit or device whose function is to control electrical energy at a specific frequency or frequency band. Different types of passive components are often used to construct different filters. These passive components include resistors, capacitors, and inductors.

●INPUT LINE FILTER input linear filter

    Refers to a power filter that is placed at the input end and connected to a circuit or combination circuit to reduce noise generated by the power supply. This filter is designed to eliminate noise in a frequency band. Usually these filters It is a low-pass filter, which means that only low-frequency signals, such as a DC power supply, are passed through to reduce high-frequency signals, which are mainly noise. Band-pass or low-pass filters are usually made up of inductors and capacitors.

●PERMEABILITY (CORE) permeability (iron core)

    The permeability of a magnetic iron core is the characteristic that makes the iron core have the ability to concentrate magnetic lines of force. The material of the iron core and the shape of the iron core will affect the "effective magnetic permeability" of a known iron core shape, size and material and specific Compared with the material of lower permeability, the magnetic material with higher permeability will have higher inductance value.

●DC-DC CONVERTER DC-DC converter

    Refers to a circuit or instrument that can convert a DC input voltage into a regulated output voltage. The output voltage can be less than, greater than or equal to the input voltage. The interactive DC-to-DC adjustment circuit requires an inductor or a voltage regulator to achieve the desired Compared with non-switching technology, the output voltage, interactive adjustment circuit has higher power efficiency.

●DIFFERENTIAL-MODE NOISE differential mode noise

    Also called normal mode noise, this kind of electrical interference does not occur in the circuit but between the circuit and the circuit.

●EMI (Electromagnetic Interference) electromagnetic wave interference

    Refers to electrical energy that is of no use, and is usually used interchangeably with Noise.

●NOISE noise

    Refers to the excess energy in a circuit that has nothing to do with the desired signal. The source of noise is usually some form of switching circuit. Common sources of noise are switching voltages, regulators and clock signals, such as some digital circuits.