Ripple

What is Ripple?

The public power network usually delivers a alternating current. In Germany the frequency is 50 Hz. For many applications in electric technology a direct voltage is required. Direct voltage can be generated by rectification. The occuring voltage does not have a constant but a ripple. The direct voltage is after the process of rectification an overloaded alternating voltage. By smoothing using a smoothing capacitator the AC component can be reduced. The ripple remaining after the smoothing is called ripple.

The smoothing capacitator is arranged after the rectifier. With an increasing course of voltage coming out of the rectifier it gets charged. In the down phase of the rectifier voltage the charge is transmitted to the user. The AC voltage share is reduced while the DC voltage share increases. The voltage at the user is smoothed.

Ripple in Practice

For power supply units the amount of ripple is usually mentioned in the data sheet. It appears for regulated power supply as well. For the selection of a power supply unit in a specific application the ripple in addition to the supply voltage, the operating frequency and other parameters have to be taken into account. The ripple is a value without dimension. If the AC voltage value is split by the DC voltage the result is the ripple.