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Ripple Voltage is voltage variation across the load and it is the AC component. To answer this question, consider a Half Wave rectifier with a smoothing capacitor: This rectifier will consist of a sinusoidal voltage source, an ideal diode, a capacitor in parallel with the load. At t=0, the voltage across capacitor = load voltage When the circuit is switched on, the capacitor is fully charged as the sinusoidal source reaches its peak. However, the sinusoidal nature causes the source voltage to decline after reaching the peak. This means that no current will flow through the diode. But the capacitor is still charged. So this will supply current to the load while it discharges. But during the discharging period (till the sinusoidal picks up again), the load voltage is an exponential function = peak voltage *exp-[(t - t')*resistance of load*capacitance] Now a key point is that the pulsating current is flowing through the diode to recharge the capacitor. Because of this constant charge and discharge of the capacitor in the cycle, the load voltage has AC ripples. At the same time load current is never zero and is directly prop to load voltage. The dc component >> ac component and the ripple voltage is greatly reduced by the capacitance esp a large one. You can minimize these by choosing a large capacitance. This is how a capacitor accounts for AC ripples. You can never actually rid these ripples even if you use a full-wave rectifier! Google search half - wave rectifier graphs on the ripples to understand this!! --- Sona

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Related Questions

How the capacitor removes the ripples from the rectified voltage?

During the AC cycle, the capacitor charges when the rectifier conducts, and maintains the voltage when the rectifier is not conducting.


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For part of the AC voltage wave, the capacitor will be above the source voltage, and will discharge until the AC voltage wave increases above the capacitor's stored voltage.


How a can capacitor smoothen or reduce the ripple of the voltage produce by the rectifier?

Rectifiers will not give a smooth DC voltage. There are ripples in the voltage given the rectifier. So in order to smoothen the voltage we use capacitor in parallel to the rectifier output. Now lets see how the capacitor smoothen the voltage that is coming from a rectifier...... Capacitor blocks DC and allows AC...... If we take the voltage that is coming from the rectifier it has some ripples in addition to DC, these ripples can be divided in to sinusoidal wave forms ( fictitious )according to the Fourier series. So the rippled DC now divided ( fictitious ) in to a pure DC and sinusoidal AC wave forms having the frequency that is multiples of ripple frequency. Now the DC current will not pass through the capacitor as the capacitor blocks DC. But the AC will pass through it i.e the ripple wave forms that are divided ( fictitious ) in to sinusoidal AC wave forms will pass through the capacitor. So only DC current enters in to the load, which will produce a pure DC voltage drop across the load. In this manner the capacitor smoothens the voltage.


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If a circuit is grounded through a capacitor it is referred to as AC ground because ac signal can pass through the capacitor DC level is blocked


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ac passes by repeatedly charging and discharging the capacitor. when you study ac circuit analysis, you will find out about impedance and reactance, which will allow you to compute how ac behaves in capacitors and inductors.


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How can I test a capacitor on an AC unit?

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