this video is about trick to remember the formula to find ripple factor and also to remember the value of half wave rectifier and full wave rectifier ripple factor values.
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The output of a rectifier is consists of a dc component and an ac component. This ac component is undesirable and cause for the pulsations in the rectifier output.
So the ac component present in the pulsating output i.e. in the rectifier output is known as Ripple.
The ratio of r.m.s. value of a.c. component to the d.c. component in the rectifier output is known as ripple factor i.e.
Ripple factor = r.m.s. value of a.c component / value of d.c. component=Iac/Idc
The ripple factor is a measure of the quality of the rectification of an AC current.
The DC output of an ideal full wave rectifier should be a "straight line" (i.e. the output should have a constant value), but due to imperfections in the rectifier design or implementation the result has "ripples" caused by an undesired AC component.
The ripple factor compares the rms value of the AC component with the value of the DC output as an indication of how "deep" those "ripples" are.
Ripple factor (γ) may be defined as the ratio of the root mean square (rms) value of the ripple voltage to the absolute value of the DC component of the output voltage, usually expressed as a percentage. However, ripple voltage is also commonly expressed as the peak-to-peak value.
Ripple voltage is an alternating (AC) voltage which is a constituent part of a composite voltage waveform with a constant DC component (offset) which may be positive or negative, but for analysis is usually considered to be an absolute value. The ripple component is often small relative to the DC component, but in absolute terms, ripple (as in the case of HVDC transmission systems) may be thousands of volts. Ripple itself is a composite (non-sinusoidal) waveform consisting of harmonics of some fundamental frequency which is usually the AC line frequency of 50/60Hz, but in the case of switched-mode power supplies, the fundamental frequency can be tens of kilohertz to megahertz. The characteristics and components of ripple depend on its source: there is single-phase half- and full-wave rectification, and three-phase half- and full-wave rectification. Rectification can be controlled (uses Silicon Controlled Rectifiers (SCRs) or uncontrolled (uses diodes). There is in addition, active rectification which uses transistors.
Various properties of ripple voltage may be important depending on application: the equation of the ripple for Fourier analysis to determine the constituent harmonics; the peak (usually peak-to-peak) value of the voltage; the root mean square (RMS) value of the voltage which is a component of power transmitted; the ripple factor γ, the ratio of RMS value to DC voltage output; the conversion ratio (also called the rectification ratio or "efficiency") η, the ratio of DC output power to AC input power; and form-factor, the ratio of the RMS value of the output voltage to the average value of the output voltage. Analogous ratios for output ripple current may also be computed.
An electronic filter with high impedance at the ripple frequency may be used to reduce ripple voltage and increase or decrease DC output; such a filter is often called a smoothing filter.
The initial step in AC to DC conversion is to send the AC current through a rectifier. The ripple voltage output is very large in this situation; the peak-to-peak ripple voltage is equal to the peak AC voltage minus the forward voltage of the rectifier diodes. In the case of a SS silicon diode, the forward voltage is 0.7V; for vacuum tube rectifiers, forward voltage usually ranges between 25 and 67V (5R4). The output voltage is a sine wave with the negative half-cycles inverted.