The article will introduce real noise the way to deal with a situation, pass with ferrite magnetism bead (inductance is big familial member, often be used at falling likewise countermeasure of a confusion of voices) will spread out a topic quite.

 

 

Of use inductance fall countermeasure of a confusion of voices

When using capacitance to cannot eliminate noise adequately only, can consider to use inductance. Fall the inductance that uses in countermeasure of a confusion of voices has two kinds roughly:

① winding inductance: Make filter

② ferrite magnetism bead: noise changeover is heat

 

Inductance and ferrite the impedance of magnetism bead is characteristic

In enter use inductance and ferrite magnetism bead falls before the countermeasure introduction of a confusion of voices, will know their main character first. Although ferrite magnetism bead the inductance that be by classify, dan Jipin is led – impedance character and common inductance are different.

 

 

Ferrite magnetism bead compare with common inductance photograph, have resistor R heft to be worth bigger, Q to be worth inferior character. Use this character to be able to eliminate noise. Additional, character of dc electric current is different also.

 

 

The dc overlay electric current with common inductance bigger admissibility, want to be inside its limits only, impedance not very suffers the effect of dc electric current, syntonic point is almost constant also. Under photograph comparing, ferrite magnetism bead easy to dc electric current saturation, saturated meeting brings about inductance value to drop, syntonic dot to high frequency paragraph of move. This meeting brings about filter character to change, because this needs special attention.

 

Begin to introduce use inductance and ferrite below the countermeasure that magnetism bead reduces noise.

 

① winding inductance: Make filter

It is below about using the introduction of the π of inductance filter. In low frequency paragraph, because inductance with capacitance play is low,know the effect of filter. Arrived high frequency paragraph, because inductance can be behaved,for capacitance, capacitance meeting expression is inductance, the effect that knows filter high arrives since π filter thereby, because this is unavailable,noise removes the effect.

 

 

② ferrite magnetism bead: noise changeover is heat

Ferrite magnetism bead in low frequency paragraph also basically rise low the effect that knows filter. But, the place before be like is narrated, in this frequency paragraph easy to dc electric current saturation, magnetism bead eliminates the ferrite that uses value of this kind of inductance to drop very hard target frequency paragraph noise.

 

Watch the graph on the right side of please next. Reactance is reduced and the dot of existence and resistor heft across. The frequency that should exceed ” of crossing of this “ that be called paragraph hind, ferrite magnetism bead the effect that will have resistance, have the function that is noise changeover heat. This is with inside the vast difference between the filter of buy winding inductance. And be in more high frequency paragraph, as identical as winding inductance, play knows the effect of filter high.

 

 

Used ferrite the filter of magnetism bead, can eliminate noise bypass not only, still can be noise changeover heat, because this hopeful realizes exceedingly good noise,remove property. But, need notices its dc slants buy electric current is characteristic.

 

The key wants a place

● is used at falling the inductance of countermeasure of a confusion of voices, can divide roughly the filter that makes for winding inductance and use ferrite magnetism bead undertakes two kinds heating up changeover.

Magnetism bead and common inductance compare ● ferrite, have resistor heft R the character with inferior value of bigger, Q.

The dc overlay electric current with the inductance bigger admissibility with common ● , want to be inside its limits only, impedance not very suffers the effect of dc electric current.

● ferrite magnetism bead sheds easy saturation to dc, saturated meeting brings about inductance value to drop, syntonic dot to high frequency paragraph of move.

The filter that ● common inductance makes, the range that optional inductance is worth is wider.

The Q of magnetism bead is worth ● ferrite inferior, because this is inside wider frequency limits,have fall outstandingly effect of a confusion of voices.