Rectifiers: Why the DC power supply is needed?

Rectifiers

Why the DC power supply is needed?

1. Electrical power is generated and transmitted and distributed in the form of AC but for operation of most of the electronic devices DC power is required.

2. Secondly dry cells and batteries have the advantage of being portable and ripple free but the voltages are low and are needed to be replaced frequently. Also its quite expensive in comparison to the conventional DC power supply.

Conventional Power supply;

The equipment that converts AC to DC is called the Dc power supply. It generally consists of 4 blocks. They are 1.the power transformer, 2. Rectifier, 3. A smooth filter, and 4. a voltage regulator.







Let’s discuss each block:

Transformer: It is used to step up or step down the supply voltage as per the need of the solid state electronic devices and circuits. It also provides isolation to the supply line.

Rectifier: It converts sinusoidal AC to positive or negative pulsating DC. A P-N junction diode is used which conducts when forward bias and practically does not conduct when reverse bias. The rectifier typically consists of one, two or four diodes. They may be either half wave or full wave or bridge rectifier.

Filter: The output of the rectifier consist of a pulsating character i.e. the unwanted AC component along with the DC component. The filter is the device that passes the DC component and blocks the AC. Filter is constructed from reactive circuit elements such as capacitors, inductors and resistances.

Voltage Regulator: Its function is to provide or maintain constant DC voltage and rejects the AC ripples if any which are not removed by the filter. It is constructed with the help of Zeners or discrete transistors or ICs.