Inductors (chokes and ferrites)
At high frequencies the inductor offers a larger voltage drop across itself (i.e. due to
its capability to offer high impedance it can limit the current to a greater extent). It
should have sufficient insulation to prevent breakdown and should also have
minimum parasitic capacitance across it. It should also be mechanically strong to
prevent stress under surge conditions. Inductors are largely used as series devices
for power line transient protection rather than in low-voltage signal or data lines. To
attenuate transients and associated noise, ceramic materials called ferrites are sometimes
used; these are representative of a series circuit with resistance and inductance.
The resistance will damp any kind of oscillations that could have resulted from interaction
of the inductance and capacitance combination in the system. For this reason,
ferrite beads are used in experiments to clean up electromagnetic interference problems
associated with measurements.