What is the Difference between half wave and full wave rectification?

Answer 1

Rectification is the process of converting AC (Alternating current) power into DC (direct current) power.

AC has current going in both directions which varies over time. Most common AC power has sinosoidal waveform, with a frequency of 60Hz in the US and Europe.

When converting AC to DC, there are two methods for rectification:

1. Half wave and 2. Full wave.

In Half wave rectification, only one half of the waveform energy is converted into DC power. The other half is ignored. The design of a half-wave rectifier is simple and more cost-effective; however, it is not very efficient; the theoretical maximum efficiency is 50%

In full wave rectification, both positive and negative waveform is rectified; this is acheived by reversing the polarity of the input connection using a diode bridge circuit; this allows to get the maximum power out of the input AC line. Disadvantages include higher cost and higher parasitic voltage drop but one can get upto 90% efficiency very easily with full-wave rectificaiton.

Answer 2

1. Half-wave rectification

A half wave rectifier is a special case of a clipper. In half wave rectification, either the positive or negative half of the AC wave is passed easily, while the other half is blocked, depending on the polarity of the rectifier. Because only one half of the input waveform reaches the output, it is very inefficient if used for power transfer. Half-wave rectification can be achieved with a single diode in a one phase supply.

In half wave rectification, either the positive or negative half of the AC wave is passed, while the other half is blocked. Because only one half of the input waveform reaches the output, it is very inefficient if used for power transfer. Half-wave rectification can be achieved with a single diode in a one phase supply, or with three diodes in a three-phase supply.

in half wave rectifier only one diode is there. The diode will be forward biased in the positive half cycle and reverse biased in the negative half cycle. So the out put will be available only during the positive half cycle and the out put will be unidirectional.

Full-wave rectificationA full-wave rectifier converts the whole of the input waveform to one of constant polarity (positive or negative) at its output. Full-wave rectification converts both polarities of the input waveform to DC (direct current), and is more efficient. However, in a circuit with a non-center tapped transformer, four diodes are required instead of the one needed for half-wave rectification. (See semiconductors, diode). Four rectifiers arranged this way are called a diode bridge or bridge rectifier:

For single-phase AC, if the transformer is center-tapped, then two diodes back-to-back (i.e. anodes-to-anode or cathode-to-cathode) form a full-wave rectifier (in this case, the voltage is half of that for the non-tapped bridge circuit above, and the diagram voltages are not to scale).

In a full wave rectifier during each half cycle one of the diode will be forward biased and output will be available across the load resistor. So we get continuous dc output throughout the cycle.

1. no.. of diods 1 in half wave rect....

Answer 3

The AC waveform is a sine wave which is above zero for 1/2 a cycle and below zero for the other half cycle. In a half-wave rectifier you essentially clip the negative so you have 1/2 a positive sine wave and then a 1/2 cycle of zero. In full-wave you effectively fold the 1/2 wave below zero to above zero so it looks like a series of "hills" one after the other and all positive. It is easier to filter a full-wave rectifier to smooth it out into a DC signal with less ripple.