EPAS 2

• This module was designed and written with you in mind. It is here to help you develop knowledge, skills, and attitudes in the performance of the Electronics Product Assembly and Servicing tasks.
• The scope of this module permits it to be used in many different learning situations. The language used recognizes the diverse vocabulary level of students. The lessons are arranged to follow the standard sequence of the course.
• The module is composed of one lesson which is all about Prepare/Make PCB Modules.
• After going through this module, you are expected to:

  • Determine common steps in designing/ making PCB modules
  • Describe some parameters that are needed in designing/ making PCB modules
  • Appreciate the importance of designing/ making PCB modules in electronics
• The PCB design-making is one of the processes in assembling an electronics product. It is a vital part of electronics assembling in which it supports the actual circuitry of a given electronic device. Proper handling of tools and equipment is required.
• All electronic circuits from the simplest to the most complex design need diagrams to be used as a reference in designing, modifying, and troubleshooting the circuit. The most commonly used electronic diagrams are schematic, pictorial, wiring, and block diagrams.
• Pictorial diagram


  Shows the pictures of the actual components and wiring connections although it does not provide the exact size of components. It shows the exact shape in proportion to the actual component or device.
• Block Diagram


  Uses a block of squares, rectangles, or triangles to represent components, groups of components, or units of equivalent. Particularly used to represent internal components of an integrated circuit.
• Schematic diagram


  Shows the components used in their interconnection. Each graphic symbol is also accompanied by a reference designation to distinguish it from other similar symbols. It does not illustrate the physical size, shape, or chassis location of the parts and devices.
• Wiring diagram


  Shows wiring connection in a simplified, easy to follow manner. It may show either internal or external connections or both and is usually drawn as simple as possible to trace out the connection of a circuit. The components of the circuit are identified by name or are represented using pictorial illustrations that do not follow any well-defined standard form.
• PCB

  Printed circuit board. A board that has lines and pads that connect various points. It also allows signals and power to be routed between physical devices. Solder is the metal that creates the electrical connections between the surface of the PCB and the electronic components.
• PCBs are often single-sided (one copper layer), double-sided (two copper layers) or multi-layer (outer and inner layers)
• Compositions of PCB

  • The base material, or substrate (FR4), is sometimes fiberglass
  • The next layer is a thin copper foil, which is laminated to the board with heat and adhesive
  • The layer on top of the copper foil is called the solder mask layer. This layer gives the PCB its green. It helps the user to solder to the proper places and stops solder jumpers
  • The white silkscreen layer is applied on top of the solder mask layer. The silkscreen adds letters, numbers, and symbols to the PCB that allow easier assembly and indicators
• PCB Making

  Understand the diagram very well in able for you to come up with an efficient and creative PCB design
• PCB Etching

  The process that uses chemicals to create copper traces to attach different components on a circuit board. Copper is removed from the board except at the places where wired connections are present. The advantages include the de-cluttering of the system and easy seeing the connections and an increase in usability and portability.
• What is Etching Process?

  1. The etching is the process of material being removed from the material's surface. The etching process sometimes involves using liquid chemicals to require off the substrate material before they're employed in fabrication.

  2. The etching process is one of the foremost steps within the final processing of printed circuit boards (PCBs). This process removes excess copper and so on, revealing the required circuit patterns. Within the PCB etching process, all copper is removed except the circuitry that's protected by the tin plating that was applied during the previous treatment in PCB manufacturing.
• Steps in PCB Etching

  1. Identify the materials

  2. PCB design - You can design your PCB based on the circuit's schematic diagram like the full-wave rectifier power supply circuit. The design can be transferred using a piece of paper, and glue it on the copper-clad board's surface. It is also made possible by using a marker pen to directly draw the PCB design. Note: The design must be placed in a mirror
• PCB Etching

  1. Identify materials

  2. Design PCB

  3. Etching

  4. Cleaning board

  5. Drilling
• PCB Etching


  • Removes excess copper to reveal required circuit patterns
  • Copper is removed except circuitry protected by tin plating
• Etching


  Chemical process that removes copper from PCB to create circuit patterns
• Etching steps

  1. Prepare ferric chloride solution

  2. Dissolve ferric chloride in warm water

  3. Put board in solution

  4. Copper removed from edges then center

  5. Etching takes 10-15 minutes

  6. Remove board, rinse, and dry
• Ferric chloride is a toxic solution, proper disposal is required
• Cleaning board


  Remove paper design, use acetone to clean surface
• Drilling

  1. Use PCB drilling machine and drill bits sized for component pins

  2. Make small impact with nail and hammer if drill slips

  3. Place board on wooden block during drilling
• PCB Checking

  1. Visual inspection for expected design

  2. Continuity testing with multimeter
• If continuity test fails, reconnect designs by soldering
• Etching is an important process in electronic products assembly to create circuit patterns on PCB
• Schematic diagram provided to create PCB design
• Online activity: Search other PCB etching methods, download pictures, and compare to methods in module
• Offline activity: Find actual PCB design of home appliances, draw and compare design and manufacturing