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. This is largely because peak-to-peak is both easier to measure on an oscilloscope and is simpler to calculate theoretically. Filter circuits intended for the reduction of ripple are usually called smoothing circuits.
The simplest scenario in ac to dc conversion is a rectifier without any smoothing circuitry at all. The ripple voltage is very large in this situation; the peak-to-peak ripple voltage is equal to the peak ac voltage. A more common arrangement is to allow the rectifier to work into a large smoothing capacitor which acts as a reservoir. After a peak in output voltage the capacitor (C) supplies the current to the load (R) and continues to do so until the capacitor voltage has fallen to the value of the now rising next half-cycle of rectified voltage. At that point the rectifiers turn on again and deliver current to the reservoir until peak voltage is again reached. If the time constant, CR, is large in comparison to the period of the ac waveform, then a reasonably accurate approximation can be made by assuming that the capacitor voltage falls linearly. A further useful assumption can be made if the ripple is small compared to the dc voltage. In this case the phase angle through which the rectifiers conduct will be small and it can be assumed that the capacitor is discharging all the way from one peak to the next with little loss of accuracy.[1]
because in the halfwave the pulses of current to recharge the filter capacitor only happen on every other AC peak instead of on every AC peak, as in the fullwave. you can get the same ripple in a halfwave, but only by doubling the filter capacitor value from that needed by the fullwave. this may be too expensive or bulky.
in full wave bridge rectifier, the input and out put voltages are same but in case of two diode rectifier the input and output voltages can be different as per requirement a there is a transformer in the circuit. The former is lighter and the later is heavier.
Half wave rectifier makes the the sinusoidal wave uni-direction only in one half cycle and leave the other but in full wave rectifier both the cycles are made uni-directional.
The output degrades to a half-wave rectifier.
Since the output of the rectifier is a close approximation of a sawtooth waveform, then all harmonics starting at the second harmonic are present in the full wave bridge rectifier output.
You use a half-wave rectifier where the system design does not require a full-wave approach. Half wave rectifier output is used for running ac motors.
in full wave bridge rectifier, the input and out put voltages are same but in case of two diode rectifier the input and output voltages can be different as per requirement a there is a transformer in the circuit. The former is lighter and the later is heavier.
Efficiency is double in case of full wave rectifier.
"What is the functioning procedure of full wave rectifier by using SCRs?" "What is the functioning procedure of full wave rectifier by using SCRs?"
It depends on whether or not it is a half wave or full wave rectifier. For a single phase 60 Hz rectifier, a half wave rectifier will be 60 Hz while a full wave rectifier will be 120 Hz. A three phase full wave rectifier will be 360 Hz.
An open diode will result in no output from a half wave rectifier, and an open diode will cut the output of a full wave rectifier in half.
The Ripple factor for full-wave rectifier is given by: r= Iac/Idc = 0.482
Bridge Rectifier DiodesIn a "bridge" rectifier there is 4 diodes In a "full wave" there are 2 diodes.In a "half wave" rectifier there is 1 diode.
full wave rectifier, because in half wave rectifier only one p-n junction diode Ans 2. In full wave rectifier both negative & positive cycles are rectified , but , in half wave rectifier only the positive or the negative cycle is rectified . That's why full wave rectifier provides more power .
A center-tapped transformer and two diodes can form a full-wave rectifier that allows both half-cycles of the AC waveform to contribute to the direct current, making it smoother than a half-wave rectifier. This form of circuit saves on rectifier diodes compared to a diode bridge, but has poorer utilization of the transformer windings. Hence we do not use centre tapping for full wave rectification.Ashish sharmaAstt. ProfessorHIET, Shahpur, kangra(H.P.)
Half wave rectifier makes the the sinusoidal wave uni-direction only in one half cycle and leave the other but in full wave rectifier both the cycles are made uni-directional.
For a center tapped full wave rectifier transformer secondary gives a voltage that is 2Vm. For a bridge rectifier it is Vm.
A bridge recifier is a full wave rectifier. It takes each part of the AC waveform, rectifies it and adds them together, giving a smoother output compared to a half wave recifier. They are used in simple power supplies, using a mains transformer, a bridge rectifier and a smoothing capacitor. Further regulation can then be added for stable power supplies.