# szhighstar's Blog

Toroidal Inductor An inductor constructed by placing a winding on a core that was a donut shapes surface, toroidal coirs are available in many magnetic core materials with in the four basic types: ferrite,powered iron, alloy and high flux and tape wound,characteristics of toroidal inductors...
Distributed capacitance In the construction of an inductor, each turn of wire or conductor acts as a capacitor plate, the combined effects of each turn can be represented as a single capacitance knows as the distributed capacitance,this capacitance is in parallel with the inductor, this parallel...
Impedance The impedance of an inductor is the total resistance to the flow of current, including the AC and DC component, the DC component of the impedance is simply the DC resistance of the winding, the AC component of the impedance includes the inductor reactance, the following formula...
SRF(Self-resonant frequency) The frequency at which the inductor's distributed capacitance resonateds with the inductance, it is at this frequency that the inductance is equal to the capacitance and they cancell each other, the inductore will act purely resistive with a high impedance at the SRF...
Saturation Current The DC bias current flowing through the inductor which causes the inductance to drop by a specified amount from the initial zero DC bias inductance value , common specified inductance drop percentages include 10% and 20%.it is useful to use the 10% inductance drop value for...
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Rated current The level of continuous DC current that can be passed through the inductor, this DC current level is based on a maximum temperature rise of the inductor at the maximum rated ambient temperature, the rated current is related to the inductor's ability to minimize the power losses in...
DCR(DC resistance) The resistance of the inductor winding measured with no alternating current, the DCR is most often minimized in the design of an inductor, the unit of measure is ohms, and it is usually apecified as a maximum rating. OHM The unit of measurement for resistance and impedance...
Q value The Q value of an inductor is a measure of the relative losses in an inductor, the Q is also knows as the "quality factor" and is technically defined as the ratio of inductive reactance to effective resistance and is represented by Q=XL/R=2pifL/R Since XL and R are functions of...
Number turns The series impedance of a high frequency ferrite device can be increased by running two or more turns of the treated conductor through the ferrites core, magnetic theory predicts that the impedance of the device will increase with the square of the number of turns, however, due to...
Inductance tolerance Standard inductance tolerances are typically designated by a tolerance letter, standard inductance tolerance letters include: F:+/-1% G:+/-2% T:+/-3% J:+/-5% K:+/-10% L:+/-15% M:+/-20% P:+/-25% N:+/-30% Test frequency The frequency at which inductors are tested for either...
Inductance The property of a circuit element which tends to oppose any change in the current flowing through it, the inductance for a given inductor is influenced by the core material, core shape and size, the turns count and shape of the coil,inductors most often have their inductances...
Inductor A passive component designed to resist changes in current,inductors are often referred to as "AC Resistor",the ability to resist changes in current and the ability to store energy in its magnetic field,account for the bulk of the useful properties of inductors,current passing through an...
INTRODUCTION:COMMON MODE CHOKES.
1. selection core: We should be know below necessary information: (a) Minimum Inductance based on DC basic, e.g. 1mH (b) IDC current, e.g. 3A According to formula LI*I= 1.0*3.0*3.0=9.0 We can find 60u which is in range from curve which is LI*I vs core part number, and find core 55586 is suitable...