What is the advantage of connecting an RC filter to the output of a diode rectifier circuit?
The RC filter attenuates the ripple voltage. With no filter and a resistive load, the output voltage varies between 0V and the peak voltage. For a first order filter (series R, then shunt C) the ripple is attenuated by 6dB per octave (for a sine wave). The filter resists change, and the faster the change the more it resists. That means sine wave frequencies higher than the cutoff frequency (Fc) are halved for each doubling of the frequency from cutoff. The capacitor acts as a reservoir. This is useful in a diode detector of an AM radio for example, where the amplitude modulated signal is rectified. This is an envelope of the modulating audio signal. The filter converts this to the audio signal, removing artifacts of the carrier signal. If the filter cutoff is 14Khz and the carrier is 455KHz, then the actual attenuation of the carrier is something like 5 x 6dB = 30dB or 32 times as a voltage ratio. With a power supply the series R is often not provided as a physical resistor, but is due
