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Basic Electronics- DC. Soldering & Circuit Fabrication. Presentation Overview. Terms and Definitions Soldering Tools & Materials and their Uses Cleaning Before & After Soldering Stripping and Tinning Soldering Procedure Characteristics of a Good Solder Connection - PowerPoint PPT Presentation

Text of Basic Electronics- DC

  • Basic Electronics- DCSoldering & Circuit Fabrication

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Presentation Overview Terms and DefinitionsSoldering Tools & Materials and their UsesCleaning Before & After Soldering Stripping and TinningSoldering ProcedureCharacteristics of a Good Solder ConnectionTypes of Poor Solder Connections & CausesTypes of Soldered Connections

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Terms and DefinitionsOxides- Films and impurities which form on the surface of metals when exposed to air or water and which , if not cleaned off, will prevent a good bond between the surfaces and solderRosin- A material obtained from pine trees which is used during soldering to help ensure a good bond between the solder and the solder and the metal surfacesWetting- The ability of molten solder to flow over and fuse completely with the metal surfaces to which it is applied (NOTE: Dirt, grease, and oxides prevent good wetting during soldering.)Stripping- Removing insulation from electrical conductors

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Terms and Definitions (contd)Tinning- The application of a small amount of solder to surfaces to be soldered to help ensure good wetting during solderingFlux- A liquid or solid which when heated cleans and protects surfaces to be solderedCrimping- Applying mechanical pressure to compress a sleeve-type or cup-type electrical terminal to ensure a good electrical connection between the sleeve and the conducting wires it containsLand- Printed wiring attached to the surface of a printed circuit boards

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Soldering Tools & Materialsand their Uses (A)Soldering Iron, 100 watt- For soldering large electrical connectionsSoldering Pencil, 10 to 35 watt- For soldering small electrical connectionsSoldering Gun, 100 watts- For soldering large electrical connections where better heat control is requiredResistance Soldering Unit- For soldering many connections in close spacesAdjustable Power Source- For controlling soldering iron tip temperature (NOTE: Variac is a commonly used adjustable power source.)Soldering iron stand- For supporting a hot soldering iron when not in useHeat sink- For drawing heat from soldered connection to prevent damage ot componentsMechanical wire strippers- For cutting and pulling insulation from ends of connectorsThermal wire strippers- For removing wire insulation by heating and melting the material; prevents removing wire strands, but cannot be used on insulation that will not melt, such as glass braid or asbestosCrimping Tool- For making a strong mechanical connection to certain sleeve-type terminalsNail Nippers- For use in clipping component leads flush with surface

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Soldering Tools & Materialsand their Uses (A)

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Soldering Tools & Materialsand their Uses (B)Component lead cleaner- For removing oxides and other films from component leadsTypewriter eraser- For removing oxides and other films from terminals to be solderedIsopropyl Alcohol- For removing oil, grease, and flux from conductors and terminals both before and after solderingSolder- For making electrical connections; most common type is 60/40 rosin-core solder containing 60% tin and 40% lead, with a center core of rosin flux to allow simultaneous application of both solder and fluxLong nose and Needle nose pliers- For making mechanical connection prior to soldering; may also be used as heat sink during solderingDiagonal cutting pliers- For cutting conductorsFlux- For ensuring a good electrical connection by cleaning and wetting all surfaces during soldering; not required if the solder contains a rosin coreSolder sucker- For removing melted solder from a terminal to be re=soldered (NOTE: There are many different brands available including Soldawick and Soldavac, etc.)Spaghetti-sleeve insulation- For preventing electrical connections from becoming shorted to adjacent connections Heat-shrink insulation- Sleeve-type insulation which, when heated, shrinks to form a snug fit over a soldered connection

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Soldering Tools & Materialsand their Uses (B)

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Cleaning before and after soldering(CAUTION: Use safety goggles or glasses when soldering)Oil, grease, and dirt- Wipe with isopropyl alcohol and clean clothOld Solder- Heat with soldering iron, and wick away, or suck up by means of a solder suckerOxides1. Component leads- Use component lead cleanerTerminals- Use typewriter eraserRosin flux- Wipe or brush with isopropyl alcohol or flux cleaner(CAUTION: Use alcohol only in well-ventilated spaces and do not permit open flames in the vicinity.)

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Stripping and Tinning

    Make clean cut at wire end by cutting off small length with diagonal cutting pliersLay wire in proper size slot of wire strippers and strip approximately one inch of insulation from wire end (CAUTION: If too small a slot in wire strippers is used for stripping, the strippers will cut off some of the wire strands. This could result in an electrical connection of higher resistance than desirable.)

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Stripping and Tinning (contd)Care must be taken not to remove wire strands when strippingIf wire strands have been separated, gently re-twist wire in same direction as original twistAfter stripping, clean the wire strands with isopropyl alcohol and paper towelPlace heat sink on wire strands immediately adjacent to wire insulation before tinningTin soldering iron tip as follows:Wrap a piece of solder around tip three or four timesPlug in unit and allow it to heat up, adjust variac to point just past where solder meltedWipe tin with moist paper towel or wet spongeAs soon as tip will melt solder, coat tip with solder; wipe off excessIf rosin-core solder will not be used, wipe small amount of liquid or paste rosin flux on bare strands of stripped wireSet hot soldering iron in holder or vise

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Stripping and Tinning (contd)Melt small bead of solder on iron tip and slowly draw bare wire through solder bead from heat sink toward wire end; apply additional solder as needed (CAUTION: After the wire has been tinned, the outline of the wire strands should be visible. If they are not, too much solder has been applied. Reheat wire and wipe off excess solder. If some strands are still loose, too little solder has been applied. Reheat wire and apply additional solder.)Remove heat sink from tinned wireAfter solder has cooled, clean the tinned wire with isopropyl alcohol and paper towel or clean cloth

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Soldering Procedure

    Clean all surfaces to be solderedStrip and tin wires to be solderedIf electrical connection is to be insulated, slide approximately one-inch length of spaghetti insulation onto the tinned wireIf possible, mechanically connect tinned wire to terminal or lug bt means of long nose or needle nose pliers, make sure distance between terminal and wire insulation is no more than 1/32 to 1/8 inch, depending on wire gauge

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Soldering ProcedurecontinuedIf mechanical connection is not possible, make sure component to be soldered is held stationary in vise or clamp to prevent movement during solderingSelect proper soldering iron for the job, depending on:Size of connectionHeat sensitivity of componentsProximity of other connections and wiresHeat and tin the soldering ironAttach heat sink as close as possible to connection without interfering with soldering operation

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Soldering ProcedurecontinuedIf rosin-core solder is not to be used, brush small amount of rosin flux on terminalWhile making sure that no part of the connection moves, apply hot iron tip to terminal and wire, and apply solder to wire, component, or terminal lead; remove iron tip and solder as soon as solder has flowed freely over, around, and through the connectionAfter solder has cooled, clean connection with isopropyl alcoholIf connection is to be insulated, slide spaghetti sleeving over connectionIf applicable, remove component from vise or clamp

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Characteristics of a Good Solder ConnectionSlivery, shiny appearance to solder surfaceGood wetting of solder to surfacesSolder completely covers connection, but contour of connection is still visible

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Characteristics of a Good Solder ConnectionInsulationNo burnt areasNo damaged insulationGap between insulation and connection is approximately the diameter of the wire insulationNo spilled solderNo pits or holes in the solder surface

    Basic Electronics- DC / Soldering & Circuit Fabrication

  • Types of Poor Solder Connections and causesCold solder joint- Insufficient heatDisturbed joint- Connection moved before solder solidifiedExcessive solder- Too much solder appliedInsufficient solder- Too little solder appliedDewetted solder joint- Insufficient cleaning or insufficient use of fluxBurnt insulation- Excessive heat or carelessness with ironInsulatio