Electrical and Electronics: Module 21

Module 21A: Introductory Printed Circuit Board Fabrication (Optional)

Suggested time: 5 - 10 hours

Level: Introductory

Prerequisites: Modules 2, 17A

Foundational Objectives

To use appropriate terminology for electricity or electronics in context.
To design and/or build circuits to an acceptable standard capable of producing a desired output.
To demonstrate the safe use and knowledge of meters and hand and power tools used in the electrical industry.

Common Essential Learnings Foundational Objectives

To strengthen knowledge and understanding of how to compute, measure, estimate and interpret numerical data and when to apply these skills and techniques. (COM)
To explore the technical, implications of present technology and of impending technological developments within the field of electronics. (TL)

Learning Objectives	Notes
PERMANENT INK METHOD
21.1 To select an appropriate size of copper clad and prepare the surface for the circuit pattern. (TL)	Obtain a piece of copper clad material and cut it to a size appropriate for the circuit being constructed.
21.2 To draw the pattern using waterproof material. (COM)	Use permanent ink, fingernail polish, lacquer or waterproof liquid paper correction fluid to draw the circuit pattern.
21.3 To etch the board in an etchant used for removing the copper.	Etchants used could be either ferric chloride or ammonium persulphate.
21.4 To drill holes to receive component leads.	Drill the holes using dental bits in a drill press or other hand-held motorized tool.

PASTE AND CUT METHODS

21.5 To select an appropriate size of copper clad material and prepare the surface for the circuit pattern. (CCT)	Obtain a piece of copper clad material.
21.6 To cover the surface of material with a film such as masking tape or commercial plastic adhesive.	Show the advantages of using different film covers. A good choice would be a clear material with an adhesive backing that can be applied directly to the copper clad material.
21.7 To draw a pattern on the film or obtain a photocopy of a pattern.	Have students draw their own pattern or photocopy a pattern and glue it to the film.
21.8 To cut out and remove the sections of the pattern that are to be etched.	Use an Exacto knife or other sharp knife to cut and remove the unwanted sections of the film from the copper clad material.
21.9 To etch the board in an etchant used for removing copper.	Etchants used could be either ferric chloride or ammonium persulphate.
21.10 To drill holes to receive component leads.	Drill the holes using dental or other small bits in a drill press or other hand-held motorized tool.

Module 21B: Advanced Printed Circuit Board Fabrication (Optional)

Suggested time: 8 - 10 hours

Level: Intermediate

Prerequisites: Modules 1, 2, 17A, 21A

Learning Objectives	Notes
PHOTOGRAPHIC METHOD
21.11 To select an appropriate size of copper clad material and prepare the surface for the pattern for the circuits. (TL)	Obtain a piece of copper clad material.
21.12 To cover correctly an unsensitized board with photosensitive material with appropriate chemistry. (CCT)	The application of either positive or negative chemistry, depending on whether a positive or negative tracing image is desired, may be sprayed or painted on in subdued light. Avoid exposure to ultra-violet light. Note: If sensitized board is used, follow appropriate instructions.
21.13 To demonstrate the correct method of exposure and development of a properly prepared board.	Contact print the image on the sensitized surface and develop in appropriate chemistry. The development step must be accomplished without additional exposure to ultra-violet light.
21.14 To etch the board in an etchant used for removing copper.	Etchants used could be either ferric chloride or ammonium persulphate.
21.15 To drill holes to receive component leads.	Drill the holes using dental or other small bits in a drill press or other hand-held motorized tool.

SILK SCREEN METHOD

21.16 To select an appropriate size of copper clad material and prepare the surface for the pattern. (CCT)	Have students choose from a selection of precut pieces or have them cut their own piece to size.
21.17 To use a prepared silk screen to print the desired pattern on the copper clad surface. (TL)	If facilities exist, the students could produce their own silkscreen pattern to the copper clad material.
21.18 To demonstrate how to etch the board in an etchant used for removing the copper from the exposed area. (IL)	Etchants used could be either ferric chloride or ammonium persulphate.
21.19 To drill holes to receive component leads.	Drill the holes using dental or other small bits in a drill press or other hand-held motorized tool.