Experts to teach you how to test magnetic core winding

Core winding since for suppression of high frequency noise of signal lines, power cords and peak interference, have the ability to absorb electrostatic pulse. Magnetic ring is used to absorb the uhf signals, as some RF circuit, PLL, the oscillation circuit, including ultra-high frequency memory circuit ( DDR SDRAM, RAMBUS, etc. ) Need to be in power input part and the circular, the inductance is an energy storage element, used in LC oscillation circuit, the low frequency filter circuit and so on, its application range rarely more than 50 MHZ. The function of the magnetic core winding (mainly is to eliminate exist in the transmission line structure Circuit) The RF noise, RF energy is superimposed on the dc transmission level of ac sine-wave component, dc component is a useful signal, need and RF RF energy is useless along the line transmission and radiation (electromagnetic interference EMI) To eliminate these unwanted signal energy, using a chip circular and play the role of high frequency resistance ( Attenuator) , the device allows dc signal through, and the ac signal filtering, high frequency signal for more than 30 MHZ normally, however, low frequency signal will be affected by the chip magnetic ring. Core coiling has high resistivity and magnetic permeability, he equivalent resistance and inductance in series, but the resistance and inductance value is changing with frequency, magnetic core winding than ordinary inductance has good high frequency filtering properties, when high frequency impedance, so can in a relatively wide frequency range of high impedance, higher frequency modulation filter effect thereby. As a power supply filter, inductor may be used. Magnetic core winding circuit symbol is the inductance but it can be seen that the use of models is the circular on the circuit function, the circular and principle of inductance is the same, just different frequency characteristics, magnetic ring is composed of oxygen magnets, inductance is composed of magnetic core and coils, magnetic ring the ac signal is converted into heat energy, inductance store communication, slow release. As long as the wire in the circuit through it ( I am using is like ordinary resistance appearance, wire has been through and agglutination, also have the form of SMT, but few see selling) 。 When the current through the wire, the little impedance, ferrite of low frequency current for high frequency current produce large attenuation effects, in which high frequency current distribution in the form of heat, the equivalent circuit of an inductor and a resistor in series, the value of the two components are proportional to the length of the circular. Circular and a lot of more phyletic, the manufacturer shall provide technical indicators show that exception is the relationship between impedance and frequency of the circular curve. Some core winding on the multiple holes, with wire through the impedance can increase the components ( Through the circular and the number of times square) , but increase the ability to restrain noise in high frequency could not as expected, and by many several series magnetic beads will be better, ferrite magnetic materials, can produce because of current through the magnetic saturation, permeability decline sharply. Large current filter structure should be adopted on specially designed magnetic ring, also notice its cooling measures, ferrite beads not only can be used to filter out high frequency power supply circuit noise, Can be used in the dc and ac output) , also can be applied to other circuit, the volume can be very small, exception is in digital circuit, due to the pulse signal with high order harmonic frequency is very high, is also a main circuit of high frequency radiation source, so can play the role of the circular on this occasion.