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 4th edition, Ronald Reis ( page 7)

Design StageConcept and Requirements are defined.

System diagram, initial schematic and initial packaging drawing are produced.

Electronic Project Design and Fabrication 4th edition, Ronald Reis (page 8 and Chap 3)

Drawing StageWorking schematic produced.

Computer testing (were appropriate) is completed.

Electronic Project Design and Fabrication 4th edition, Ronald Reis (page 8 and Chap 4)

Experimentation StageCircuit 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 4th edition, Ronald Reis (page 8 and Chap 6)

Prototyping StagePCB artwork rendered.

First PCB made and components mounted.

Final package drawing.

Electronic Project Design and Fabrication 4th 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 4th 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 SourceBatteryWall TransformerDual SupplyBuilt 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 ComponentsParts should be readily availableCost of componentsSurface Mount vs Insertion MountPackage typeRatings of components

Heat sinks required? Special mounting requirements?

Other ConsiderationsCostEase of assemblyEase of maintenanceSize of completed deviceUser interface and ergonomicsSpecial tools or equipment required for

assembly

StandardsProjects 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 ProjectDoes 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 4th edition, Ronald Reis (pages 53-54)

Design DrawingsSystem 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 4th 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 4th edition, Ronald Reis (page 45)