Introduction

     I , Jessica Balidoy and my partner Jorrel Olivar, both enrolled in Tech 101, are required to make a  POWER SUPPLY, for us to pass in this subject. 

    A power supply is a hardware component that supplies power to an electronic device. It receives power from an electrical outlet and converts the current from AC to DC, which is what the computer requires. It also regulates the voltage to an adequate amount, which allows the computer to run smoothly without overheating. The power supply is an integral part of any computer and must function correctly for the rest of the components to work. (http://www.techterms.com/definition/powersupply)

     In making this device, first we have to have a complete set of materials needed in making it.  Our instructor, Miss Arrianne Michelle Florendo, made us an offer, if we ordered from her it will cost us Php 680. We tried to canvassed outside the campus  but it will cost us too much. So we grab our instructor's offer, I and my partner shared for the payment. As the materials arrived we started making it. 

Here are the step-by-step process :

Power Supply (The Making Part I)

Power Supply (The Making Part II)

Power Supply (The Making Part III)

Power Supply (The Making Part IV)

 

Definition of Terms

Capacitors - consists of metal foils separated by a layer of insulating film.


Diodes - a device that is a two-terminal electronic component that conducts electric current in only one direction

Drilling - is a cutting process that uses drill bit to cut or enlarge a hole in solid materials. It cuts by applying pressure and rotation to the workpiece, which forms chips on the cutting edge.

Etching -   is the process of using strong acid or mordant to cut into the unprotected parts of the  metal surface to create a design.

Ferric Chloride - a chemical used to dissolve the metal (copper) in the printed circuit board.

Printed Circuit Board - used to mechanically support and electronically connect electronic components using conductive pathways.

Resistor -is a linear, passive two-terminal electrical component that implements electrical resistance as a circuit element.

Soldering - is a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the workpiece.

Transformer - is a device that transfers electrical energy from one circuit to another through inductively coupled conductors.

Power Supply (The Making Part I)

         For us to pass this subject ,Tech 101, our instructor required us to submit an electronic device in which we should make by ourselves, I and my partner.

      A power supply is used to supply energy to one or more electronic loads. Every power supply must obtain the needed energy it supplies to its loads. The type of this power supply we made is an Electronic Energy Transmission System, which converts AC line voltage to DC line voltage.

First Day {Sept. 13,2011}

     On this day, our instructor gave us the needed set of materials, which we ordered from Manila, in making our power supply. This set of material consists of  2  pieces printed circuit board, 4 pieces of diodes, 1 piece of resistor, 2 pieces of capacitors, lead, ferric chloride, fuse, switch and the case.

First Step: Cleaning the PCB 

     On this day, we started to make our own printed circuit board. First, using the sand paper, Jessica smoothed the edges of the board, for us to avoid cuts on our hands. Then Jorrel, cleaned the solder part until no unwanted spots and fingerprints can be seen on the board.

Cleaning the PCB using an eraser.

Second Step: Designing the PCB

     Next thing we did, Jessica covered the solder side with masking tape and made sure there was no air between the tape and the board to prevent the ferric chloride in dissolving the essential part of the PCB.
      

     A copy of the design was given, for us to use as a pattern for the PCB. Beneath it, was a carbon paper that helped in tracing the design. Jorrel covered it on top of the masking tape and Jessica traced the design and shaded it after.

Copying the design of the given pattern for the PCB.

The result outcome of the pattern.

Cutting the untraced part using a cutter.

     The purpose of cutting part is to allow the ferric chloride in dissolving the untraced part of the board, so that traced part will remain.

Third Step:  Etching the PCB

     

     Before etching we made sure that the weather is very hot to have a successful outcome. Using gloves, we prepared a small container and put enough amount of ferric chloride on it to cover the whole PCB. In less than 10 minutes of waiting, the copper of the uncovered part has been dissolved by the ferric chloride.

Soaking the PCB with Ferric Chloride.

 Note : In etching , better doing it outside, but made sure its not direct to sunlight.

     After soaking, Jessica pulled the PCB out of the container and placed it under running water. Jorrel gently wiped the wet board by a soft cloth, and here is the outcome after etching;

This is how it looks after etching.

Power Supply (The Making Part II)

Second Day {Sept. 16,2011}

Forth Step: Drilling the PCB

        

       At the Electronics Room, only one hand drill was available to use. So we let other groups to finish first and we just waited for our turn. Finally,its our turn, I let Jorrel do the drilling. We patterned the holes from the given design and size of the PCB. The purpose of this holes is where to attach or fix the components (soldering) and where to insert the wires for connecting to other components.

     Drilling with 0.8mm drill bits can be a bit tricky as it's easy to break the drill bits. Always hold the drill straight and do not bend it when the hole has started. Putting a soft block of wood under the PCB provides a good base to drill into.

Proper way in drilling a PCB

Fifth Step:  Placing the Components on the PCB

    Jessica placed the components [consist of four diodes, two capacitors and a resistor ]according to the given pattern or design forthe printed circuit board.

Arrangement of the components on the PCB.

   

Power Supply (The Making Part III)

Sixth Step:  Parts of the Power Supply

On this part, we placed the other parts on the case.  

    

On this Figure  = = = = = = >

   There is the switch, fuse and the connecting wire (which will be the plug of the power supply).

< = = = = = =  On This Figure

    We can see the inside of the case, DC selector and the two outputs.

On this Figure  = = = = = = >

      Top view inside the case of Power supply.

< = = = = = =  On This Figure

  Fixing the Transformer inside the case with screw.

Power Supply (The Making Part IV)

Seventh Step : Soldering the Components and Connecting Wires

     On this part, we are soldering the wires to be connected using the lead and soldering rod.

 Wires had been connected to the DC Selector.

Soldering the Components in the PCB.

 Placing the Printed Circuit Board inside .

After all the processes, finally it was finished.

Checking the Power Supply

    

      It was September 29, 2011 , Thursday, when I and my partner decided to be check our power supply. Our instructor Maam Florendo, put our power supply in a box together with Mike and Jinalyn's power supply. Then she test if our power supply passed the quality control. How?  About  one and a half meter above the floor, she dropped the box. Ouch! Then, when our power supply was already on my hands, she grab it quickly and dropped it again. Ouch! for the second time. 

     After, we opened our PS to check if the parts had destroyed. Unfortunately, our PCB broke, but maam said, it will still works. So we felt relieved! Then she, cut the wire (4.5v) connected in the rotary switch to test if the wiring is correct. We plugged our PS to the outlet, placed the dynamo on the OUTPUTS (+,-),  when I switched it on,it didn't work at all. We felt very disappointed! We found out that our rotary switch was also destroyed, therefore we didn't pass the test. :(

    Luckily, our instructor have such a good heart, so, she gave us second chance to repair our power supply. So we immediately replaced the rotary switch of the PS. Then on the next day, September 30,2011, Friday, we test again our PS if it is working properly after the repair. Then ma'am Florendo said the magic word  "PASS". We are very very happy after we heard that four-letter word. We even have a picture with our very kind and beautiful instructor, Miss Arrianne Michelle Florendo. Here it is,

Left to Right: Jorrel Olivar, Miss Arrianne Florendo, Jessica Balidoy

GOODBYE TECH 101!  :))