DIY Mobile Phone Battery Charger Circuit

Introduction

All Electronic circuit operates by using DC voltage or DC current. But sometimes electronic circuits require AC Voltage or Current, so to convert that AC to DC we use PN junction Diode.this process of conversion is known as Rectification or Rectifier.

Diode-Diode allows current only one direction i.e., forward bias condition and blocks in reverse bias. 

What is Rectifier?

A Rectifier is an electrical device that converts an Alternating Current(AC) into Direct Current(DC) by using one or more diodes.

                                              

• Always we don't get pure DC current from diode instead we get pulsating DC current i.e., either positive or negative half cycle. 
• To avoid this problem we use capacitors to filter the pulsating DC current to pure DC current.

                          

Types of Rectifier

• Half Wave Rectifier.
• Full Wave Rectifier.

Half Wave Rectifier

Half wave rectifier can be constructed by using a single diode, step down transformer and resistive load.

         

• The transformer is used to step down the high AC voltage applied at the primary winding to a very low AC voltage at the secondary winding which will be applied to the diode.
• The diode will be forward biased during the positive half cycle then current flows through the diode.
• Diode blocks current during the negative half cycle.

                      

                         Input and Output of Half Wave Rectifier

Full Wave Rectifier

The full-wave rectifier can be constructed by two ways

1. Centre tapped full-wave rectifier.

     2. Bridge Rectifier.

Centre tapped full wave rectifier    

               

• Centre tapped transformer is also known as a two-phase transformer. At the centre of the secondary winding, the connection is made which is at zero potential.
• During the positive half cycle, diode D1 conducts so current passes through it and D2 doesn't conduct, it blocks the current. 
• During the Negative half cycle, diode D2 conducts so current passes through it and D1 doesn't conduct, it blocks the current. 
• The combination of the two half-wave rectifier becomes a full-wave rectifier and it converts both half cycles of the AC signal into pulsating DC signal.

Full Wave Bridge Rectifier

• The main advantage of the bridge rectifier is, it doesn't require the center tap transformer thereby reducing its size and cost.
• Bridge Rectifier consists of four diodes, transformer, and resistive load.

                             

• Unlike center tap rectifier it has single winding used for both halves of the cycle.
• During the positive half cycle, diode D1 & D3 conducts so current passes through it and D2 & D4 doesn't conduct, it blocks the current. 
• During the Negative half cycle, diode D2 & D4 conducts so current passes through it and D1 & D3 doesn't conduct, it blocks the current. 

Mobile phone Battery charger Circuit

All electronic products in our home use AC voltage through the rectifier circuit that converts AC into DC  like laptop charger,mobile phone charger, etc.

Components Required

• Transformer
• Diode
• Capacitors
• Voltage regulator

Circuit Diagram

                               

                  

• The transformer steps down the voltage from 230v to 6v which is further given to the bridge diode.
• Diode converts the AC voltage to Pulsating DC voltage this process called rectification.
• To get pure DC voltage from pulsating DC, the capacitor filter is used and this part we call it as smoothing.
• Finally, a voltage regulator is used to maintain a constant voltage here IC 7805 provides constant 5v voltage at the output.