INDUCTOR FILTERS use an inductor called a choke to filter the pulsating dc input. Because of
the impedance offered to circuit current, the output of the filter is at a lower amplitude than the input.
PI-TYPE FILTERS use both capacitive and inductive filters connected in a pi-type configuration.
By combining filtering devices, the ability of the pi filter to remove ripple voltage is superior to that of
either the capacitance or inductance filter.
VOLTAGE REGULATORS are circuits designed to maintain the output of power supplies at a
constant amplitude despite variations of the ac source voltage or changes of the resistance of the load.