The difference between the inductor and the beads
The habits of more than one turn of coil called inductance coil, less than one turn (the wire through the ring) the habits of the coil called the bead;
Inductance energy storage component, and the beads are energy conversion devices (consumption);
The inductors are used for power filtering circuit, the beads used for the signal circuit for EMC countermeasures;
Bead is mainly used to suppress electromagnetic radiation interference, and the inductor used in this area is focused on the inhibition of conductive interference. Both can be used to deal with EMC, EMI;
Inductance is generally used to match the circuit and signal quality control in the combination of analog and digital ground magnetic beads.
Beads have a high resistivity and magnetic permeability, he equivalent series resistance and inductance, resistance value and the inductance value versus frequency. Better high frequency filtering characteristics than ordinary inductance, showing resistance at high frequencies, they are able to maintain a high impedance in a wide frequency range, thereby enhancing the FM filter effect.
, You can use as a power supply filter inductor. The circuit symbol of the bead is inductance model can be seen on the use of circuit functions on the beads, beads and inductors is the same principle, but the frequency characteristics.
Beads by oxygen magnets, the inductor core and coil beads conversion of the AC signal to heat, the inductor exchange stored, slow release out.
Beads for high-frequency signals have a greater impediment, General Specifications 100 ohm / 100mMHZ resistance at low frequencies is much smaller than the inductance.
Ferrite beads (Ferrite Bead) is an anti-interference component application development quickly, cheap, easy to use, to filter out high frequency noise effects significantly.
Circuit wires through it can (I use are like ordinary resistors look like wire through and glue, but also in the form of surface mount, but rarely seen selling). When the current through the wire, ferrite on the low-frequency current is almost what impedance will have a greater attenuation of high frequency current. The high-frequency current in which the form of heat distribution, the equivalent circuit of an inductor and a resistor in series, the value of the two components are proportional to the length of the bead. Bead types, the manufacturer should provide technical indicators instructions, especially bead impedance vs. frequency curve.
Some beads have multiple holes with a wire through the increase component impedance (through the square of the number of beads), but increased at high frequencies the noise suppression capability can not be as expected, but with more than series a few beads of the way would have been better.
Ferrite magnetic materials, magnetic saturation, permeability will be generated by current sharp decline. The high current filter specially designed bead structure, but also pay attention to its cooling measures.
Ferrite beads can be used not only to the power supply circuit to filter out high frequency noise (can be used for DC and AC output), can be widely used in other circuits, its volume can be made very small. Is the main source of digital circuits, due to the high harmonic pulse signal contains high frequency, is also a circuit of high frequency radiation, so on this occasion to play the role of the beads.
Ferrite beads are widely used in noise filtering of the signal cable.
Commonly used in power supply filtering HH-1H3216-500, for example, the meaning of each field in the model followed:
HH is one of its series, mainly used for power supply filtering for the signal line is the HB series;
1 indicates a component that encapsulates a bead, if for 4 is a side-by-side package to four;
H denotes the composition of the material, H, C, M-IF applications (50-200MHz),
T lower frequencies (50MHz), S high-frequency applications (200 MHz);
3216 package size, length 3.2mm, width 1.6mm, or 1206 package;
500 impedance (typically at 100MHz), 50 ohm.
Product parameters, there are three:
Impedance [Z] _AT_ 100MHz (ohm): Typical 50, the Minimum 37;
DC resistance DC the Resistance (m ohm): the Maximum 20;
Rated current Rated Current (mA): 2500.