The filter capacitor converts the full
-
wave rippled output of the rectifier into a
smoother DC output voltage. Generally for DC power supply circuits the filter
capacitor is an
aluminium electrolytic type that has a capacitance value of 100
μ
F or more with repeated DC
voltage pulses from the rectifier charging up the capacitor to peak voltage. However, there
are two important parameters to consider when choosing a
suitable filter capacitor and these
are its
Working Voltage
, which must be higher than the no
load output value of the rectifier
and its
Capacitance Value
, which determines the amount of ripple that will appear
superimposed on top of the DC voltage