A rectifier is an electronic circuit that converts alternating current (AC) into direct current (DC) by allowing the flow of current in one direction only. Both the full wave rectifier and half wave rectifier are types of rectifier circuits, but they differ in terms of efficiency and the amount of AC waveform that gets converted into DC.
- Half Wave Rectifier: A half wave rectifier allows the passage of only one half (either positive or negative) of the input AC waveform while blocking the other half. It consists of a single diode connected in series with a load resistor. When the input AC voltage is positive, the diode conducts and allows the current to flow through the load resistor, resulting in a positive half-cycle output. When the input AC voltage is negative, the diode blocks the current, resulting in zero output. As a result, the output waveform is a pulsating DC waveform with a frequency that is twice that of the input AC waveform.
The main advantage of a half wave rectifier is its simplicity, as it requires only one diode. However, it has a lower efficiency compared to a full wave rectifier since it utilizes only half of the input AC waveform.
- Full Wave Rectifier: A full wave rectifier allows the passage of both positive and negative half-cycles of the input AC waveform. It can be implemented using two diodes and a center-tapped transformer or using a bridge rectifier circuit. The center-tapped transformer configuration uses a transformer with a center-tapped secondary winding, while the bridge rectifier circuit uses four diodes arranged in a bridge configuration.
In the full wave rectifier, during the positive half-cycle of the input AC voltage, one diode conducts and allows the current to flow through the load resistor, producing a positive output. During the negative half-cycle, the other diode conducts and the current flows in the opposite direction through the load resistor, resulting in a positive output again. This configuration ensures that both halves of the input AC waveform contribute to the DC output, resulting in a smoother DC waveform with less ripple compared to a half wave rectifier.
The full wave rectifier has higher efficiency compared to the half wave rectifier since it utilizes the entire input AC waveform. It is the more commonly used configuration for rectification purposes.
In summary, the key difference between a full wave rectifier and a half wave rectifier lies in the amount of AC waveform they convert into DC. The full wave rectifier uses both positive and negative half-cycles, resulting in a smoother output, while the half wave rectifier uses only one half-cycle, resulting in a pulsating output waveform.