Linear Power Supply Advantages And Disadvantages

Abstract

This report explains the basic concepts of linear power supplies and switching mode power supplies (SMPS). The main difference between the two supplies is the way they operate. A switched mode power supply provides a changeable voltage. It works by constantly switching the source on and off; the rate of which is dictated by the required voltage at the output while the power provided by linear power supplies provide a constant voltage at all times.

The complexity of a switched mode power supply make it so hard to use as it requires an inductors whereas a linear power supply is often used because of it is simplicity. It is only need a rectified voltage source to operate.

In terms of advantage and disadvantage of both supplies, the

Introduction

A linear power supply is a type of voltage convertor that uses a transformer and a rectifier to convert AC voltage into DC voltage. It contains four basic components: a transformer, rectifier, filter capacitor, and voltage regulator. In this chapter, we will investigate each part of a linear power supply and illustrate the main advantages and disadvantages of using such a supply power. Figure 1.1: linear power supply circuit (williamson-labs,2016)

1.2. Transformer

A transformer, as the name implies itself, it transforms high voltage electricity from power station to lower voltage electricity. This technique used to save energy when electricity travel from the power plants to our home. The transformer builds to reduce an AC voltage in linear power supply. So the concept of how it work is based on very simple fact when current flows through a wire, it creates a magnetic field and by passing other wire and wrapping them around core it will reduce the

Rectifier

In linear power supply the full wave rectifier is used to produce full positive sine wave. The process used four diodes that arrange in series pairs with only two diodes attaching current during each half cycle. The first diode and the second diode are connected in series while the other two diodes are reverse biased in positive half cycle of the supply. This process repeats itself in negative half cycle. By adding a capacitor beside a rectifier circuit, it reduces AC component which raise the average output voltage and supply current when the output voltage decreases as figure 1.2 Shown below.

Figure 1.2: diode bridge rectifier (electronicstutorials,2016)

1.4. Voltage regulator

Voltage regulator is a system used to insure a steady voltage after rectifier it in linear power supply circuit. The resistance of the regulator changes in accordance with the load due to a constant output voltage. The voltage regulator chip is made to function like a variable resistor, constantly modifying a voltage divider to preserve a constant output voltage, and continually receding the difference between the input and the output voltages as waste heat.

1.5. Advantage and