Even if it is connected with a voltage well below its dielectric strength, the effect occurs with a time delay. If it is connected upside down, this layer dissolves and the capacitor becomes low impedance. It has an oxide layer between the plates, which is designed only for the flow of current in one direction. “Normal” capacitors are among the less sensitive components and can usually be connected in both directions.īut beware: The frequently used electrolytic capacitor, short Elco, is sensitive to a wrong connection. Some devices simply will not work if they are connected with the wrong polarity, while others will be damaged. Polarity is important for many components of DC technology to ensure smooth functioning. On the other hand, if the capacitor is too large, its large charging current can destroy the diodes for rectification or overload the cables.
This can affect the functions of consumers or even cause damage. If the capacitor chosen is too small, it does not smooth the voltage fully, and a high residual ripple remains.
This is why the ripple of the input voltage is slight when it reaches the consumer – the capacitor maintains the voltage.Ī properly-sized capacitor can smooth not only a sinusoidal voltage but also pulse width modulation (PWM). However, due to the rectifier circuit, it cannot send the charge back to the voltage source, but discharges it via the consumer.
When it drops below a certain level, it discharges. While the voltage reaches its highest values, the capacitor is charged. The capacitors help to fill in the gaps in the rectified voltage. Here, a capacitor is as close as possible to the rectifier circuit and the second as close as possible to the consumer. Often, two smaller smoothing capacitors are used instead of one large one. The capacitor for voltage smoothing is placed parallel to the load behind the rectifier circuit. Our online filter capacitor calculator helps with dimensioning the capacity. We want to explain how a smoothing capacitor can be dimensioned and how exactly it works. However, it may not be infinitely large, as the diodes could be damaged. The remaining ripple is called the ripple voltage.įor a voltage with as little residual ripple as possible, the capacitor must be the right size. Although the capacitor does not produce perfect DC voltage, it reduces the fluctuations to a level that most devices can easily handle. Experts speak of a high ripple.Ī smoothing capacitor, also called a filter capacitor or charging capacitor, is used to “smooth” these voltages. However, this circuit has a big disadvantage: It works only from the lower half-wave upwards and leaves a pulsating DC voltage. Most commonly, the rectifier circuit is constructed with a bridge rectifier consisting of four diodes. When connecting these devices, the voltage must be rectified in advance. However, many devices are operated with a DC voltage. The German power grid supplies a sinusoidal AC voltage with a frequency of 50 Hz. General information about the smoothing capacitor Areas of application – Smooth voltage with capacitor.Explanation – Calculate smoothing capacitor.Calculate smoothing capacitor – formula.General information about the smoothing capacitor.