Project: DC Power Supply(PCB) Group Members: Haris Abbas Qureshi 171000 M Zubair Khan 170907 M Ammar Aslam 170928 Department of Electrical and Computer Engineering . Air University,Islamabad

1. Project Report
Submitted to:Sir Engr Waqar Shami
Project: DC Power Supply(PCB)
Group Members:
Haris Abbas Qureshi 171000
M Zubair Khan 170907
M Ammar Aslam 170928
Department of Electrical and Computer Engineering
. Air University,Islamabad

2. DC Power Supply: Electricity comes in two main
forms: alternating current (AC) and direct current (DC). DC current
has the flow of electricity going in only one direction (forwards),
whereas AC current has the electricity going in two directions
(backwards and forwards). DC current is easier for smaller devices to
utilize and is the most common method of power supply for anything
that runs on battery power as well.
Power supplies:
Most electrical power from a wall outlet comes in alternating
current form
AC to DC conversion
Alternating current must be converted to direct current (DC)
by a rectifier.
Rectifier:
The bridge rectifier is one of the most widely used rectifier
circuits. It offers a high level of performance when compared
to other rectifier circuits.
In view of the high level of use of the bridge rectifier circuit,
bridge rectifiers are available as blocks containing all the
diodes contained in a single "component" for use within the
target circuit assembly.

3. The use of these bridge rectifiers simplifies their use and the
assembly of the final equipment as well as reducing the
overall component count.
Bridge rectifier circuits:A diagram of the basic bridge
rectifier circuit is shown below. The circuit has the advantage
over the full wave rectifier using a centre tapped transformer
that there is no centre tapped transformer requirement and that
the both halves of the cycle are used in the winding.
Full wave bridge rectifier
The diagram shows the current flow for the different halves of
the cycle and in the different arms of the bridge rectifier
circuit.
Full wave bridge rectifier with transformer input
DC Power Supply(Description /Working)
The Output obtained from Rectifier is Pulsulating DC

4. Filter/Smoothing: The Pulsulationg effect can be
removed by using capacitor as a Filter.The capacitor charges
when the voltage is high and discharges as the voltage is low.
With the help of the capacitor, the voltage curve looks like
this:

5. Regulation: The Output obtained from the Filter is not
constant it may be greater or lesser than our requirement
therefore we Regulator in series after capacitor which fix the
output at fix value example if we use LM7812 then it fix the
output at 12V.Similarly there are wide verities of Regulator
available in market.
The output obtained after Regulator look like
Power Supply Requirement(Output)
 12V DC
 1Amp
Componenets/Equipments Used:
 12V Transformer
 1N4001 Diodes x4
 1000uF Capacitor x1
 0.1uF Capacitor x1

6.  0.33uF Capacitor x1
 LM7805 Regulator x1
 T block x2
 PCBx1
 Wires
 Heat Sink x1
 Led x1
 1k ohm resistor x1
12V Power Supply Circuit Diagram
Proteus is used to making the Schematics of Power Supply the
screenshots of Proteus is shown below.
PCB layout

7. The PCB is also designed in Proteus using Ares.The
Screenshot of PCB designing is given below.
Calculation for Capacitor:
c=
𝐼
𝑓𝑉
f=100Hz
V=2V(Ripple Voltage)
I=1Amp
C=5000uF
But we use 1000uf instead of 5000uF as this is not
available..and 1000uF works fine.
Final Project:

9. Final Outputs/Results:
Voltage : 11.7V
Short circuited Current :2.xx Amp
Error Percentage(Voltage):{12-11.7/12}*100=2.5V
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