Magnetic beads are used to absorb UHF signals, such as some RF circuits, phase-locked loops, oscillation circuits and circuits containing UHF memories, so it is necessary to add magnetic beads to the power input part.
Magnetic beads have high resistivity and permeability, which is equivalent to the series connection of resistance and inductance, but the values of resistance and inductance change with frequency.
Extended data
Magnetic beads can be used as power filters, and so can inductors. The circuit symbol of magnetic beads is inductance, but it can be seen from the model that magnetic beads are used. In terms of circuit function, the principle of magnetic beads and inductors is the same, but the frequency characteristics are different.
Some magnetic beads have multiple holes, and the impedance of the assembly (the square of the number of times the magnetic beads pass) can be increased by wires. Ferrite beads can not only be used to filter high-frequency noise in power supply circuits (for DC and AC outputs), but also be widely used in other circuits.
Ferrite bead is a kind of anti-interference component with rapid application, which is cheap and easy to use, and has obvious effect of filtering high-frequency noise. Ferrite beads are also widely used for noise filtering of signal cables.
Baidu Encyclopedia Magnetic Beads (Electronic Components)