What is mean by full wave Rectification?

Rectification is the process of converting an alternating current (AC) into a direct current (DC) by allowing current to flow in only one direction. This is typically done using a device called a rectifier, which can be a diode or a bridge rectifier. The output of a rectifier is a pulsating DC signal that can be further smoothed out using capacitors and other circuit elements. Rectification is an important process in electronics and is commonly used in power supplies, audio amplifiers, and other electronic devices that require a DC voltage or current.

What is full wave rectification process?

Full wave rectification is a process of converting an alternating current (AC) into a pulsating direct current (DC) by allowing current to flow in only one direction using a diode or a bridge rectifier. In a full wave rectifier, both halves of the AC waveform are utilized to produce the output, resulting in a smoother DC output than a half wave rectifier. This process is commonly used in electronic devices such as power supplies, radios, and televisions.

How to Describe the input and output waveforms for full wave rectifier

In the Figure single phase, a sinewave signal is applied to the input of a rectifier. Each cycle of a sinewave is divided into two parts one is positive and another is the negative half cycle. That shows us sinewave alternating current continuedly to switch polarity and magnitude. For a clear and smooth DC voltage, we need to convert this input AC signal into a single polarity. Combining negative and positive half cycles at one side of the zero line is called the rectification process. The rectified output is single polarity and alternating amplitude. This alternating amplitude is called ripples or pulsating DC. A capacitor Filter is used to smoothen rippled output.

Average output voltage of full wave rectifier

The average voltage of a full-wave rectifier is:

V_avg = (2V_max/π) – (2V_f/π)

where Vmax is the maximum voltage of the AC input signal and V_f is the forward voltage drop of the diode. This formula assumes an ideal diode with zero forward voltage drop. In reality, the diode will have some non-zero forward voltage drop, which will cause a slight reduction in the average output voltage.

RMS value of output voltage of full wave rectifier

The RMS value of the output voltage of a full-wave rectifier is:

V_rms = (V_max – V_f/2) / √(2)

where Vmax is the maximum voltage of the AC input signal and V_f is the forward voltage drop of the diode.

Note that this formula assumes an ideal diode with zero forward voltage drop. In reality, the diode will have some non-zero forward voltage drop, which will cause a slight reduction in the RMS output voltage.

Peak inverse voltage of half wave rectifier

The peak inverse voltage (PIV) of a full-wave rectifier is the maximum voltage that appears across the diode when it is reverse biased. For a full-wave rectifier with a center-tapped transformer, the PIV is equal to twice the peak voltage of the input AC signal, and it can be calculated using the following formula:

PIV = 2V_p

where V_p is the peak voltage of the AC input signal.

For a full-wave bridge rectifier, the PIV is equal to the peak voltage of the input AC signal, and it can be calculated using the following formula:

PIV = V_p

where Vp is the peak voltage of the AC input signal. Note that in both cases, the PIV assumes an ideal diode with zero reverse breakdown voltage. In reality, the diode will have some non-zero reverse breakdown voltage, which will affect the PIV.

Crest factor of full wave rectifier

The crest factor of a full-wave rectifier is the ratio of the peak voltage of the output signal to its RMS voltage. For a full-wave rectifier, the output voltage is essentially a series of pulses that are twice the frequency of the input AC signal. The crest factor can be calculated using the following formula:

Crest Factor = V_p / V_rms

where Vp is the peak voltage of the output signal, and Vrms is the RMS voltage of the output signal.

For a full-wave rectifier with no filter capacitor, the output voltage will have a relatively high crest factor, typically around 1.414 (or √2). However, when a filter capacitor is added to smooth the output waveform, the crest factor will be reduced, and it will depend on the capacitance value, load resistance, and frequency of the input signal.

Full wave rectifier Ripple Factor

The ripple factor of a full-wave rectifier is a measure of the amount of AC voltage ripple that remains in the output voltage after the rectification process. The ripple factor can be calculated using the following formula:

Ripple Factor = V_r / V_dc

where Vr is the RMS value of the AC component of the output voltage (i.e., the ripple voltage), and Vdc is the DC component of the output voltage (i.e., the average output voltage).

For a full-wave rectifier with no filter capacitor, the ripple voltage can be quite large, typically around 40% to 50% of the peak-to-peak value of the input AC voltage. However, when a filter capacitor is added to smooth the output waveform, the ripple voltage is greatly reduced, and the ripple factor approaches zero. In practice, the actual value of the ripple factor will depend on the capacitance value, load resistance, and frequency of the input signal.

Full Wave rectifier Efficiency

The efficiency of a full-wave rectifier is the ratio of the DC power output to the AC power input. It represents how effectively the rectifier is able to convert the input AC power into DC power. The efficiency of a full-wave rectifier can be calculated using the following formula:

Efficiency = P_dc / P_ac

where Pdc is the DC power output and Pac is the AC power input. For a full-wave rectifier with no filter capacitor, the average DC output power can be calculated as:

P_dc = (2 * V_m / π)^2 / R_L

where Vm is the peak voltage of the input AC signal and RL is the load resistance. The AC power input can be calculated as:

P_ac = V_m^2 / (2 * R_L)

where Vm is the peak voltage of the input AC signal and RL is the load resistance. When a filter capacitor is added, the efficiency can be increased since the capacitor smooths out the output voltage and reduces the amount of AC ripple. In practice, the actual value of the efficiency will depend on the capacitance value, load resistance, and frequency of the input signal.

Full wave rectification circuits

AC to DC rectification is performed by rectifier circuit. There are Two types of rectifier one is Single Phase full wave rectifier and other is Polyphase Full Wave rectifier.

Single Phase rectifiers

There are two main types of Single Phase full wave rectifier circuits: center-tapped and bridge rectifier.

1. Center-tapped full wave rectifier: This circuit uses a transformer with a center-tapped secondary winding and two diodes. The center-tap is connected to the ground, and the two outer ends of the secondary winding are connected to the diodes. The diodes conduct in alternate half-cycles of the AC waveform, allowing current to flow in one direction through the load.
2. Bridge rectifier: This circuit uses four diodes arranged in a bridge configuration to rectify the AC waveform. The AC input is connected to the two diagonal corners of the bridge, and the DC output is taken from the other two corners. The diodes conduct in alternate half-cycles of the AC waveform, allowing current to flow in only one direction through the load.

Both types of full wave rectifier circuits produce a pulsating DC output that can be further filtered and smoothed to provide a more stable DC voltage or current.

Polyphase rectifiers

Three phase and multi phase AC voltage also converted into DC voltage with different neutral phases combinations. There are two types of Polyphase rectifier one is controlled and other is uncontrolled rectifiers

Uncontrolled Rectifier: Uncontrolled rectifiers uses general purpose PN junction diodes. for each phase one diode is required to rectify concerned phase.

Controlled Rectifier: Controlled rectifiers uses thyristors and IGBTs or other switching devices to have an control on output wave form. Controlled rectifiers can control duty cycles of input AC wave and DC output voltage.