1001ENG Engineering Practice and Sustainability Introduction to Electronics

ECE Structure Lectures: Lectures: Introduction to Electronics Introduction to Electronics Component Identification Component Identification Mechanical Workshop Mechanical Workshop Electrical Safety Electrical Safety Electrical Specification and Datasheets Electrical Specification and Datasheets Labs: Labs: GRUB (weeks 1-3) GRUB (weeks 1-3) Soldering and fault-finding (weeks 4-5) Soldering and fault-finding (weeks 4-5) Power Supply (weeks 7-12) Power Supply (weeks 7-12)

Resources Maxwell website: Maxwell website: maxwell.me.gu.edu.au maxwell.me.gu.edu.au go to course information – 1001ENG go to course information – 1001ENG Required equipment: Required equipment: Power supply – mechanical:$37.65 Power supply – mechanical:$37.65 Power supply – electrical:$13.70 Power supply – electrical:$13.70 Bikelight kit:$4.30 Bikelight kit:$4.30 Toolkit:$40.75 Toolkit:$40.75 All items are kept by you at end of labs All items are kept by you at end of labs If you have all toolkit items already, you need not purchase it If you have all toolkit items already, you need not purchase it All items can be purchased from the Science Store in N34 All items can be purchased from the Science Store in N34

Laboratory Information Bikelight: Bikelight: simple soldering exercise to build a set of flashing lights simple soldering exercise to build a set of flashing lights undertaken in the week 4 lab session, takes approximately 2 hours to complete undertaken in the week 4 lab session, takes approximately 2 hours to complete all instructions are on the maxwell website all instructions are on the maxwell website graded by attendance and final result (5%) graded by attendance and final result (5%) Fault-finding: Fault-finding: groups are supplied with non-working bikelights, and must find the faults groups are supplied with non-working bikelights, and must find the faults an assessed exercise contributing to 5% of the course grade an assessed exercise contributing to 5% of the course grade

Power Supply Project The major project undertaken during this course The major project undertaken during this course A group project, however each student builds their own PSU A group project, however each student builds their own PSU 5 person groups 5 person groups each member has a specific role each member has a specific role Assessment: Assessment: worth 25% of the total marks for the course worth 25% of the total marks for the course mark is based on attendance, quality of work and final report mark is based on attendance, quality of work and final report All PSUs are thoroughly tested for electrical safety All PSUs are thoroughly tested for electrical safety The final working (??) power supply is yours to keep and use The final working (??) power supply is yours to keep and use

Roles within Groups General Manager: General Manager: oversees all aspects of development oversees all aspects of development responsible for all bookings and communication responsible for all bookings and communication must be able to step in to any other role if required must be able to step in to any other role if required Assembly Manager: Assembly Manager: responsible for guiding group through the PCB population stage of the project responsible for guiding group through the PCB population stage of the project must attend the assembly managers’ workshop in week 5 (PM) must attend the assembly managers’ workshop in week 5 (PM)

Roles within Groups Workshop Manager: Workshop Manager: must attend layout and metalwork course in week 7 (PM), and instruct remainder of group must attend layout and metalwork course in week 7 (PM), and instruct remainder of group responsible for booking metalwork workshop for group and ensuring all members complete on time responsible for booking metalwork workshop for group and ensuring all members complete on time Construction Manager: Construction Manager: responsible for the construction phase of the project – assembling the case, transformer and PCB responsible for the construction phase of the project – assembling the case, transformer and PCB ensures all safety precautions are taken during construction, and checks all PSUs in the group ensures all safety precautions are taken during construction, and checks all PSUs in the group must attend the construction workshop in week 8 (PM) and instruct remainder of group during next lab must attend the construction workshop in week 8 (PM) and instruct remainder of group during next lab

Roles within Groups Quality Assurance Manager: Quality Assurance Manager: responsible for the testing and specification phase of the project responsible for the testing and specification phase of the project must organise group during fault correction and specification labs must organise group during fault correction and specification labs must attend the QA managers workshop in week 8 (PM) must attend the QA managers workshop in week 8 (PM) All group members: All group members: must participate during each normal lab session must participate during each normal lab session are responsible for the safety and cleanliness of the laboratory are responsible for the safety and cleanliness of the laboratory should act in a responsible manner at all times should act in a responsible manner at all times must inform the demonstrator of any inappropriate and/or dangerous activities in the lab must inform the demonstrator of any inappropriate and/or dangerous activities in the lab

Basics of Electronics There are two types of skills an electronics engineer requires: There are two types of skills an electronics engineer requires: Theoretical: Theoretical: maths and electronics theory necessary to design circuits and systems maths and electronics theory necessary to design circuits and systems can be taught by lectures, textbooks, etc.. can be taught by lectures, textbooks, etc.. Practical: Practical: physical skills required to implement designs physical skills required to implement designs includes such things as soldering, mechanical skills, assembly, fault-finding, etc.. includes such things as soldering, mechanical skills, assembly, fault-finding, etc.. must be practiced regularly to maintain proficiency must be practiced regularly to maintain proficiency

Soldering Soldering is the process of joining two electronic components by applying a molten conducting metal alloy Soldering is the process of joining two electronic components by applying a molten conducting metal alloy typically soldering is used to attach components to a printed circuit board (PCB) or similar typically soldering is used to attach components to a printed circuit board (PCB) or similar Soldering serves two purposes: Soldering serves two purposes: establishes a mechanical connection between the PCB and the component so it doesn’t fall off establishes a mechanical connection between the PCB and the component so it doesn’t fall off establishes an electrical connection between the PCB and the component to transmit and electrical signal establishes an electrical connection between the PCB and the component to transmit and electrical signal Being able to solder correctly and efficiently will save you a lot of time and headaches in future years Being able to solder correctly and efficiently will save you a lot of time and headaches in future years

What is Solder? Solder is a metal alloy with a low melting point used to metallurgically join electronic components together Solder is a metal alloy with a low melting point used to metallurgically join electronic components together typical solder is a tin/lead alloy typical solder is a tin/lead alloy certain percentage alloys actually have a lower melting point than either tin or lead! certain percentage alloys actually have a lower melting point than either tin or lead! 63/37 tin:lead is the ‘best’ ratio (Eutectic point), however 60/40 is also very common 63/37 tin:lead is the ‘best’ ratio (Eutectic point), however 60/40 is also very common Solder also typically contains ‘flux’, which is used to clean oxidisaion from the surfaces to be joined Solder also typically contains ‘flux’, which is used to clean oxidisaion from the surfaces to be joined also keeps air from the joint while soldering and assists in wetting also keeps air from the joint while soldering and assists in wetting note that this does not clean dirt, oil, rust, etc from the surface note that this does not clean dirt, oil, rust, etc from the surface most commonly used solders have a flux core most commonly used solders have a flux core Solder for traditional PCB use comes in wire form, of various diameters Solder for traditional PCB use comes in wire form, of various diameters

Solder Melting Points Tin/Lead Ratio Melting Point (C) 0/ / / / / / /0232

The Soldering Iron A soldering iron is a device used to apply heat to solder, allowing it to melt in the desired location A soldering iron is a device used to apply heat to solder, allowing it to melt in the desired location The temperature of the iron can be controlled using the “Curie effect” The temperature of the iron can be controlled using the “Curie effect” The tip of a soldering iron is specially designed and must be treated with care The tip of a soldering iron is specially designed and must be treated with care this is the ‘wettable’ part of the iron, the part to which solder will ‘stick’ this is the ‘wettable’ part of the iron, the part to which solder will ‘stick’

The Soldering Iron You should always ensure that: You should always ensure that: you are soldering on a heat-resistant surface you are soldering on a heat-resistant surface the tip is kept ‘wet’ when in use, that is it has a thin coating of solder on it at all times the tip is kept ‘wet’ when in use, that is it has a thin coating of solder on it at all times you do not abrade the tip of the iron you do not abrade the tip of the iron the iron is not left turned on when not in use the iron is not left turned on when not in use the temperature is not set too high the temperature is not set too high After use, you should: After use, you should: clean the tip with a damp sponge clean the tip with a damp sponge apply a coating of solder to the tip apply a coating of solder to the tip allow to cool before storing allow to cool before storing

Correct Soldering Technique Place the components to be soldered into the correct holes in the PCB Place the components to be soldered into the correct holes in the PCB the legs should protrude onto the side with the copper tracks the legs should protrude onto the side with the copper tracks the component should be pushed fully onto the surface of the PCB where possible the component should be pushed fully onto the surface of the PCB where possible wires should be ‘tinned’ or coated with solder before being placed onto the board wires should be ‘tinned’ or coated with solder before being placed onto the board Turn the PCB over and secure firmly Turn the PCB over and secure firmly Heat the joint with the soldering iron Heat the joint with the soldering iron touch both the component leg and the copper track simultaneously touch both the component leg and the copper track simultaneously allow to heat for 2-3 seconds allow to heat for 2-3 seconds Apply the solder to the joint Apply the solder to the joint hold against the iron, component leg and PCB hold against the iron, component leg and PCB you should see smoke as the flux in the solder burns off you should see smoke as the flux in the solder burns off remove solder after the smoke disappears (about 2 seconds later) remove solder after the smoke disappears (about 2 seconds later) finally, remove the soldering iron from the joint finally, remove the soldering iron from the joint

Correct Soldering Technique

Good and Bad Joints

Things to Consider The copper on PCBs is held onto the fiberglass with glue The copper on PCBs is held onto the fiberglass with glue this glue melts at 150C while solder melts at 180C! this glue melts at 150C while solder melts at 180C! this is a design feature which allows the copper to move slightly as it expands with heat this is a design feature which allows the copper to move slightly as it expands with heat To prevent damage to the PCB, don’t: To prevent damage to the PCB, don’t: apply too much pressure with the iron apply too much pressure with the iron move the PCB or iron excessively while heating move the PCB or iron excessively while heating design PCBs with very small unconnected copper regions design PCBs with very small unconnected copper regions

Surface Mount Soldering A newer soldering technique where components are soldered onto the top of the PCB A newer soldering technique where components are soldered onto the top of the PCB much smaller PCB area required much smaller PCB area required considerably more precise considerably more precise more efficient use of PCB space more efficient use of PCB space Requires a more complicated approach Requires a more complicated approach good eyesight and/or a magnifier and a steady hand are required good eyesight and/or a magnifier and a steady hand are required apply a bead of solder to one pad, then apply flux to all pads apply a bead of solder to one pad, then apply flux to all pads move the component into position and apply heat to the bead of solder, ensuring a correct position move the component into position and apply heat to the bead of solder, ensuring a correct position apply solder to each other connection ensuring good wetting apply solder to each other connection ensuring good wetting reheat first connection again to ensure good connection reheat first connection again to ensure good connection

Surface Mount Soldering