110MT160KB

Diodes - Bridge Rectifiers

A bridge rectifier is a configuration of four or more diodes assembled together in a bridge circuit to achieve full-wave rectification. This type of rectifiers is most commonly used to convert an AC voltage into a DC voltage. A bridge rectifier is the most commonly used way of achieving full-wave rectification in circuits for use in 110MT160KB applications.

The 110MT160KB application field consists of the control and power electronics systems for industrial machinery, motor drives, variable frequency drives, insulated gate bipolar transistor (IGBT) inverters, and other power electronics applications. In these applications, the full-wave rectified voltage from the bridge rectifier is to be used as the supply power to the electronic circuits. Bridge rectifiers deliver an output with a consistent polarity and so are favored over other rectifiers in applications that require only DC power. The use of full-wave rectification also reduces the ripple current in the circuit, providing a smoother output.

Working Principle

The basic operation of a bridge rectifier is relatively simple. The four diodes are arranged in the same configuration as a bridge with the AC input source connected between the two outermost terminals and the DC output taken from the two innermost terminals. Depending on the polarity of the input, current can only flow through the diodes one way, meaning that each alternation of the input voltage will produce a pulse of current flowing in the same direction. This is known as full-wave rectification.

In a bridge rectifier, the diodes are arranged so that when the incoming AC signal is positive on one side of the bridge, the current will flow from the positive input, through two of the diodes, and out of the negative output. When the incoming AC signal is negative on one side of the bridge, the current will flow the other way, from the negative input, through the other two diodes, and out of the positive output.

The output of a bridge rectifier is not a pure DC signal; it is a pulsed direct current. The pulsed signal is usually smoothed with filters (in most cases electrolytic capacitors), which change the output from a pulsed signal to a steady DC value. Therefore, the bridge rectifier is only the first step in the power supply design.