Introduction to Design

Five Stage Electronic Design and Fabrication Process Design Stage Drawing Stage Experimentation Prototyping Stage Testing / Troubleshooting / Final Documentation Electronic Project Design and Fabrication 4 th edition, Ronald Reis ( page 7)

Design Stage  Concept and Requirements are defined.  System diagram, initial schematic and initial packaging drawing are produced. Electronic Project Design and Fabrication 4 th edition, Ronald Reis (page 8 and Chap 3)

Drawing Stage  Working schematic produced.  Computer testing (were appropriate) is completed. Electronic Project Design and Fabrication 4 th edition, Ronald Reis (page 8 and Chap 4)

Experimentation Stage  Circuit is bread boarded and/or wire wrapped and tested.  Results from testing are documented.  Modifications to circuit are corrected on schematics. Electronic Project Design and Fabrication 4 th edition, Ronald Reis (page 8 and Chap 6)

Prototyping Stage  PCB artwork rendered.  First PCB made and components mounted.  Final package drawing. Electronic Project Design and Fabrication 4 th edition, Ronald Reis (page 8 and Chap 7, 8 and 9)

Testing, Troubleshooting and Final Documentation  Test results documented.  Final drawing set produced.  Working prototype completed.  User instruction document produced. Electronic Project Design and Fabrication 4 th edition, Ronald Reis (page 8 and Chap 8 and 10)

Design Considerations

What does the customer want? Source Unknown

Technology  Analog  Digital  CMOS  TTL  Programmable Logic  Micro-controller  Microprocessor  DSP  Mixed solution

Power Source  Battery  Wall Transformer  Dual Supply  Built in Power Supply Hint: To determine whether a battery is practical for a project, calculate the current draw of the project and compare to the battery’s Amp Hour Ratting.

Environment Temperature Humidity Moisture Vibration Dust and Dirt Electromagnetic and Electrostatic Conditions Environmental factors that should be considered while designing a project. These factors include:

Electronic Components  Parts should be readily available  Cost of components  Surface Mount vs Insertion Mount  Package type  Ratings of components  Heat sinks required?  Special mounting requirements?

Other Considerations  Cost  Ease of assembly  Ease of maintenance  Size of completed device  User interface and ergonomics  Special tools or equipment required for assembly

Standards Projects should conform to pre-existing standards. For example:  Audio projects should have jacks compatible with existing headphones.  Computer projects should conform to RS- 232, USB, PCMCIA, Parallel Port ….  Equipment for industrial control should conform to Current Loop, HART…..

Safety of Project  Does the completed project meet all state and federal laws.  Potential shock, burn, fire or other hazards.  Underwriters Laboratories Inc. (UL)  Conformite Europeenne (CE)

Concepts and Requirements Document This document should answer the following questions:  Why should the project be undertaken?  What are the design requirements?  How are those requirements going to be met?  Who will do what when? Electronic Project Design and Fabrication 4 th edition, Ronald Reis (pages 53-54)

Design Drawings  System Diagram – a block diagram illustrating the functional units that make up the system.  Initial Schematic – a rough drawing of all circuits in the system.  Packaging Plan – a sketch showing what the final product might look like. Electronic Project Design and Fabrication 4 th edition, Ronald Reis (page 54)

Electronic Component Function Electronic components can be classified into passive or active components.  Passive components: A component that does not create or amplify energy. The components also help active components carry out their function. Examples: Resistors, Capacitors and inductors.  Active components: A component that is capable of controlling voltages or currents to produce gain or switching action in a circuit. Examples: Vacuum Tubes, Transistors, IC’s, Microprocessors. Electronic Project Design and Fabrication 4 th edition, Ronald Reis (page 45)