What are the three common forms of rectifier circuits (principles of rectifier circuits)
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What are the three common forms of rectifier circuits (principles of rectifier circuits)

Posted Date: 2024-01-13

What are the three common forms of rectifier circuits?

Common rectifier circuits have the following three forms:

1. Single-phase half-wave rectifier circuit: The single-phase half-wave rectifier circuit is the simplest form of rectifier circuit. It uses a diode to remove the negative half cycle of the input AC signal and outputs a unidirectional pulsating DC signal. Half-wave rectifier circuits are low cost, but relatively inefficient.

2. Single-phase full-wave rectifier circuit: The single-phase full-wave rectifier circuit uses two diodes to form a bridge rectifier, which rectifies the negative half-cycle and positive half-cycle of the input AC signal respectively to obtain a pulsating DC signal, and obtains a relatively stable DC voltage at the output end. . Full-wave rectifier circuit has high efficiency and output stability, and the common form is bridge rectifier circuit.

3. Three-phase rectifier circuit: The three-phase rectifier circuit is used for rectification of three-phase AC power supply. It usually uses six diodes or three thyristors for rectification, and can obtain the output DC voltage directly from the three-phase AC power supply. The output voltage of the three-phase rectifier circuit is relatively stable and can provide higher power.

These rectifier circuits have applications in different types of power supplies and power requirements.

What is the difference between rectified output voltage and direct current?

The rectified output voltage is different from DC in the following points:

1. Direction: The rectified output voltage is obtained after rectification on the basis of the AC signal. The current direction has only one direction during the positive half cycle or the negative half cycle. Direct current, on the other hand, is a current whose direction is always fixed and flows in one direction (usually forward).

2. Ripple: The rectified output voltage will have ripples. Since the rectification process can only filter out the negative or positive half-cycle of the AC signal, the output voltage will pulsate or ripple. The voltage of DC is constant and has no ripple.

3. Average value and peak value: The average value of the rectified output voltage will be smaller than its peak value. During the rectification process, since only part of the cycle of the signal is used, the average value of the output voltage will decrease. The average value of DC is equal to its peak value because its voltage is constant.

4. Transition characteristics: There is a certain delay and fluctuation in the rectified output voltage during the transition process. Due to the processing time of the rectifier circuit on the input signal and the lag of the output voltage, the rectified output voltage may fluctuate greatly at the switching moment. The transition characteristics of direct current are smoother.

The voltage of the rectified output is volatile and directional, and its average value is smaller than the peak value. Direct current, on the other hand, has constant voltage, direction and transition characteristics that are smoother.

Rectifier circuit principle

A rectifier circuit is a circuit that converts AC signals into unidirectional DC signals. The principle of the rectifier circuit is as follows:

1. Single-phase half-wave rectifier circuit:

A single-phase half-wave rectifier circuit usually consists of a diode, load resistor and filter capacitor. From the input AC power supply to the circuit, the anode of the diode is connected to the AC input terminal, and the cathode is connected to one end of the load resistor. When the negative half cycle of the input signal begins to flow through the load resistor, the diode is in the conducting state, and the circuit load will obtain electrical energy; while in the positive half cycle, the diode is in the off state, and there is no voltage output at the output terminal. At this time, the remaining ripple current is removed through the filter capacitor to ensure output stability.

2. Single-phase full-wave rectifier circuit:

A single-phase full-wave rectifier circuit usually consists of a bridge rectifier, load resistor, and filter capacitor. The bridge rectifier consists of four diodes, which convert both the negative half cycle and the positive half cycle of the input AC signal into a unidirectional current. The negative half cycle of the AC signal flows through diodes D2 and D4, and the positive half cycle is handled by D1 and D3. The output current becomes a stable DC voltage after passing through the filter capacitor. This rectifier circuit converts all input signals into unidirectional current, and the output is a more stable DC voltage.

3. Three-phase rectifier circuit:

Three-phase rectifier circuit is a rectifier circuit used for three-phase alternating current. It usually uses six diodes or three thyristors for rectification, and can obtain the output DC voltage directly from the three-phase AC power supply. In a three-phase rectifier circuit, six diodes (or three thyristors) rectify the positive and negative half-cycles of each phase to produce a DC signal. The DC signal is then filtered through the filter capacitor to produce a more stable DC voltage output.

Through the combination of components such as diodes, bridge rectifiers, and even thyristors, the DC signal can be extracted from the AC signal and a stable DC voltage can be obtained at the output end.

Review Editor: Huang Fei


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