<P> Voltage regulation is based on a different principle than filtering: it relies on the peak inverse voltage of a diode or series of diodes to set a maximum output voltage; it may also use one or more voltage amplification devices like transistors to boost voltage during sags . Because of the non-linear characteristics of these devices, the output of a regulator is free of ripple . A simple voltage regulator may be made with a series resistor to drop voltage followed by a shunt zener diode whose Peak Inverse Voltage (PIV) sets the maximum output voltage; if voltage rises, the diode shunts away current to maintain regulation . </P> <P> Ripple is undesirable in many electronic applications for a variety of reasons: </P> <Ul> <Li> ripple represents wasted power that cannot be utilized by a circuit that requires direct current </Li> <Li> ripple will cause heating in DC circuit components due to current passing through parasitic elements like ESR of capacitors </Li> <Li> in power supplies, ripple voltage requires peak voltage of components to be higher; ripple current requires parasitic elements of components to be lower and dissipation capacity to be higher (components will be bigger, and quality will have to be higher) </Li> <Li> transformers that supply ripple current to capacitive input circuits will need to have VA ratings that exceed their load (watt) ratings </Li> <Li> The ripple frequency and its harmonics are within the audio band and will therefore be audible on equipment such as radio receivers, equipment for playing recordings and professional studio equipment . </Li> <Li> The ripple frequency is within television video bandwidth . Analogue TV receivers will exhibit a pattern of moving wavy lines if too much ripple is present . </Li> <Li> The presence of ripple can reduce the resolution of electronic test and measurement instruments . On an oscilloscope it will manifest itself as a visible pattern on screen . </Li> <Li> Within digital circuits, it reduces the threshold, as does any form of supply rail noise, at which logic circuits give incorrect outputs and data is corrupted . </Li> </Ul> <Li> ripple represents wasted power that cannot be utilized by a circuit that requires direct current </Li>

Significance of ripple factor in full wave rectifier