Power Supply Document (1)

8/10/2019 Power Supply Document (1)

1/15

COLLEGE OF ENGINEERING COLLEGE OF COMPUTER STUDIES

Department of Electrical and Electronics Engineering

DC POWER SUPPLY

PROJECT

Submitted by:

COMO, Nigel Brett D.

SAJISE, Sharmaine M.

Submitted to:

Engr. Sarcos

Submitted on:

October 8, 2014


2/15

I. INTRODUCTION

In order to make a DC Power Supply, the first thing we have done to come up

with some ideas on how we want our power supply to work based on the requirementsgiven to us which is to produce a Voutwhich ranges from 0 Volts -12 Volts. After coming

up with the desired concepts we drew a schematic circuit diagram with the help of

National Instruments Multisim and Ultiboard. The DC Power Supply should produce a

Vout which ranges from 0v to 12v so we ran simulations with the Multisim app and found

out that it exceeds our minimum requirement of 12 Volts. After finishing the desired

layout shown on Figure 1 below, we transferred it to the Ultiboard app, arranged and

traced the necessary connections as shown on Figure 2 at which we viewed its

supposed actual output using 3d view. After the Ultiboard, we constructed it on the

breadboard to test if the design is working in actual scenarios shown n Figure 3. Once it

is tested, the layout was printed using an inkjet printer and a transparency film shown inFigure 4. Then we prepared the materials to be used for the construction of the power

supply.

Figure 1: Multisim Schematic Diagram

Figure 2: Ultiboard 3d View


3/15

We prepared the materials to be used for the pre-sensitized circuit board. The

materials used are pre-sensitized circuit board, photoresist developer, ferric chloride,

and acetone.

The pre-sensitized circuit board is cut with the desired size and then we peeledoff the white film. After that we attached the transparency film to the pre-sensitized

circuit board using a small picture frame and scotch tape to hold it. Before exposing it to

the UV light (in our case we used a regular 14W lamp shade), the surrounding should

be be dimmed of light. The exposure should be around 30minutes or more to ensure

that the design will be intact with the circuit board.

Figure 3: Bread boarding of the Schematic

Diagram

Figure 4: Printed Layout


4/15

Prepare the photoresist developer solution, the measurement should be 1 liter of

water per pack of the chemical. Before performing it, we have to wear gloves because

the solution is dangerous. Mix the solution with the water thoroughly before placing the

circuit board. Shake the PCB with the mixed solution to wash away the undesired part

and leaving the photoresist that was exposed to the light. Once the design showed up

remove the PCB on the solution and wash it through running water to stop the reaction.

Etch the copper using the ferric chloride. Place the PCB in the basin with the

ferric chloride and shake it. As soon as all the copper is etched away, remove the PCB

and wash it again thoroughly with running water. Dry the PCB using a clean cloth and

then using the acetone remove the photoresist. After that the PCB is now ready to be

drilled and to be attach with the components. The whole process is shown in the

Figures below.

Figure 5: Etching Process


5/15

After placing all of the components, solder the parts to hold it tightly. Check if

there are connections. If theres error re-do the soldering. Once it is finished, place the

constructed circuit board in its casing.

II. PRINTED CIRCUIT BOARD DESIGN

Figure 6: Soldering and Packaging

Figure 7: PCB Copper Tracings

(a)(b)


6/15

Explanation:

The flow of the circuit is from right to left in the Figure 7 (a) shown above. The

first box labeled in Figure 7 (b) represents the input of the circuit which contains thebridge circuit that consists of 4 1N4007 diodes. The second box represents the filter

component of the power supply that contains a 2200uF 35V capacitor. Following the

flow of the circuit, the third box contains the indicator whether the circuit is already

turned on or not. The indicator component that we placed is a 5mm LED. The fourth box

is the resistor for overcurrent protection of the LED. The fifth box is resistor for the zener

diode. The sixth box represents the regulator component which is the 1N4753A zener

diode. Placed after the regulator is the variable component which changes the voltage

output. This component is the 5kpotentiometer contained in the seventh box. Lastly

the eighth box which contains the smoothing capacitor of 1uF.

Materials Used:

1Pre-sensitized (+) acting PCB w/ developer

1Ferric Chloride

1220V to 12-0-12V transformer

1Fuse

Figure 8: Materials


7/15

1SPST

12200uF Capacitor

11uF Capacitor

41N4007 Diode

1 - 1N4753A Diode

21.2kresistor

15mm LED

15KPotentiometer

Errors:

There were few errors which we have performed during the etching and

assembly. During the Photoresist process, we forgot to measure the volume of water to

be mixed with the developer solution and mixed water with the ferric chloride solution

resulting into improper etching of some copper parts. We repeated the whole process

and completed it as we want it to be. During the assembly in the soldering part of theprocess, we overexposed the components to the heat of the soldering tip thereby

damaging it and is unusable. This resulted into the shiny parts that could be seen in the

PCB as we de-solder the components. We have also used improper wattage of the

resistors resulting into the burning out of the resistors. We have also used excessive

soldering lead which resulted into its overflowing and followed the copper tracings.

III. COMPONENTS LAYOUT

To solder the part and the wirings, the soldering iron should be heated first.

Using the lead and the soldering iron put it on the part where you would want to connect

the wires or to hold the parts. Do not use too much soldering lead because it can

overflow and would not stick to the right part.


8/15

The Figure above shows the Components layout and the Wiring layout of the

PCB. This was done using the ultiboard.

Figure 9: Finished output of the

Soldering process

Figure 10: Components and Wiring Layout


9/15

IV. PACKAGE OF THE POWER SUPPLY


10/15

V. TESTING


11/15

Explanation:

We tested the Circuit if it could produce our desired output after soldering. The

output shows 0.1 V26V. After the testing of the PCB alone, we placed it inside the

packaging and tested it again if it still produces the same output. After finding out that

everything is fine. We finally placed labels on the packaging.

VI. LEARNING OUTCOMES

Nigel Brett D. Como

During the construction of this project, we have learned and explored thingswhich are new to us and refined our mastery of some things which we already know of.

We consulted different sources of information in the internet, books, upperclassmen and

professors.

To start with our project, we came up with some raw concepts on how we want

our power supply to work and what items we would use. During our planning process,

my partner and I have decided to go with a Zener diode regulated power supply to

lessen the complexity of our project since its still new to us. For us to have an idea onhow our power supply would work, we used a computer application from National

Instruments named Multisim. We learned how to use Multisim and simulated different

situations for our power supply circuit. After our circuit worked fine with the Multisim

app, we went through our design and listed the needed components. We learned how to

determine which components fits best with our power supply and learned how to look

into their limitation and capabilities with the help of their respective data sheets. The

Data sheets helped us make adjustments with our power supply.

After finalizing our circuit design, my partner and I used another application from

National Instruments named Ultiboard and converted our circuit design into a PCB

design. We learned how to use the ultiboard app and trace the components connection

for the actual PCB output. We learned that the schematic diagram we came up with

needed footprints which represent its actual appearance on the board. After tracing the

copper connections on the board, it is ready to be printed. We then went to RAON and

looked for the necessary parts. We learned that each component that we know virtually


12/15

have some additional specs that we didnt expect it to have. So we bought some

components of same values but with different specs. After buying the components we

are now ready to move with the PCB making.

To convert our PCB design into an actual PCB we used a pre-sensitized (+)

acting PCB. We learned how to transfer our design as we follow the instructions of the

label. After 30 minutes of exposure to light, we removed the PCB and soaked it into the

developer solution while agitating it regularly. Once the figure showed, we rinsed the

board with running water. We learned that the longer we let the board exposed to the

light, the better the results are and if the board is soaked too long, some part of the

design would be dissolved. Once developed, we soaked it to the etching solution. We

learned how to etch the PCB with the use of Ferric Chloride solution which dissolves the

unwanted copper parts.

Our PCB design is now ready for drilling. We learned how to drill holes into the

PCB and learned how delicate the drill bits for PCB are. Before finally plugging in the

components in the holes, we used the breadboard to test the circuit in actual scenarios.

We learned that the ideal situations that we had in Multisim were a little different from

the actual. We learned that resistors could burn out if its wattage isnt observed

carefully. We learned how to de-rate components to avoid malfunctions and added a

safety device which is the fuse. When our design worked fine we now moved to the

PCB soldering.

During the soldering process, we learned how to solder components to the board

but we made few errors resulting into the shiny marking in the PCB itself. We learned

that exposing components to the heat of the soldering tip for too long could damage

components which in our case happened and prompted us to change the components.

After soldering, we learned how to choose the right size for our packaging for us to have

enough space to place all components. Finally, we tested our power supply for any

malfunctions which could have risen. Now our Zener Regulated Power Supply is done.


13/15

Sharmaine M. Sajise

We have learned a lot of things during the construction of the DC Power Supply

project. There are many new things that we have encountered. There are also mistakes

that helped us to investigate, study and analyze whats wrong and that increased our

knowledge about that topic.

By our own efforts we learned how to design a schematic circuit that have certain

requirements. We have learned how to use the Multisim and the Ultiboard which helped

us in simulation. After accomplishing the design and having it tested via Multisim we

came up with materials to be used. Since the concept is new to us, we decided to use a

Zener diode to regulate the power supply. We have printed the schematic diagram with

a transparency film and then we attach it to the pre-sensitized circuit board to mix with

the solutions. We have learned what are the dos and donts. We have experiencedseveral errors too. We have learned what is the proper way to expose the PCB on the

UV lighting and also the proper measurement and time to place the PCB with the

photoresist developer and ferric chloride.

Once the PCB is ready we head to drilling it and putting up the parts. This is our

first time to drill and it is somewhat difficult because the drill bits are too small and frail.

Despite the fact that the design worked perfectly fine with the Multisim still we have

constructed the parts in the breadboard. After a successful testing we have soldered the

parts. Soldering the parts will hold the components in place. This is also a new thing

that we have learned. It is quite hard to solder the parts. There are also a lot of

scratches or markings found in our PCB, indicating that we were amateurs. After the

completion of soldering the parts we put the PCB in its casing. Lastly, we have to check

and test wheter our power supply is working. And at last, there are no further errors and

we came up with a Zener diode regulated power supply which produces a Voutof 0.1V

to 26.1V.


14/15

VII. PICTURES OF THE FINAL DC POWER SUPPLY

DC POWER SUPPLY


15/15

Explanation:

After some few tweaks and adjustments our DC Power Supply is ready and is

producing an output of 0.1 Volts to 26 Volts. We used a prefabricated casing and made

few adjustments like placing more holes and erasing the labels. We placed proper

labels on the packaging for easy identification and now its done.

Power Supply Document (1)

Documents

Transcript of Power Supply Document (1)