Electrical Workshop PREPARED BY Academic Services Unit August 2012 Applied Technology High Schools, 2012
Module Objectives Upon successful completion of this module, students should be able to: 1. Identify soldering functions. 2. Remove and replace components on Printed Circuit Boards. 3. Identify the different accessories needed for soldering and desoldering. 4. Assemble, solder and test the electronic circuit using the PCB developed during the course of the previous module. Module Contents: Topic Page No. 6.1 Introduction to Soldering/De-soldering 3 6.2 Soldering/De-soldering Equipment and Accessories 4 6.3 How to solder and de-solder 5 6.4 Class and Lab Activities 8 6.5 Review Exercise 10 2
ATE210 Electrical Workshop 6.1 Introduction to soldering/de-soldering What is soldering/de-soldering? Soldering is a quick and efficient method of joining metals permanently. Figure 6.1a illustrates the soldering process. However, de-soldering is a method of removing the solder and components from circuit boards. Figure 6.1 b shows the de-soldering process. (a) (b) Figure 6.1: (a) Soldering process, (b) De-soldering process Soldering Functions Soldering is used for: 1. Providing mechanical support by attaching various electrical components to PCBs 2. Providing electrical contact between the component leads and conducting paths on the PCBs. De-soldering Functions De-soldering is used for: 1. Troubleshooting PCBs 2. Repair purposes 3. Components replacement 3
6.2 Soldering/De-soldering Equipment and accessories The following table shows basic solderong/desoldering tools and accessories, their usage and pictures. Tool Name Usage Picture Soldering iron Soldering iron provides heat to melt solder. Solder wire Solder wire is an alloy made up of tin and lead. It is used to join components lead to the board De-soldering pump Sucks the melted solder out of the joint Soldering iron stand Soldering iron stand is a heat resistant stand for the soldering iron. 4
ATE210 Electrical Workshop Tool Name Usage Picture Clamps are used to hold the Clamps PCB for support while soldering. Magnifying Glass helps to see Magnifying Glass tiny components leads and investigate soldering joints. Wet Wet sponge sponge cleans the soldering tip from the solder 6.3 How to solder/de-solder? Soldering steps: No. 1 Description Illustration Clean your PCB using PCB eraser Clean the soldering tip with a wet sponge 2 to remove dirt and oxide Place the component to be soldered in position on the board. Verify that the 3 component is positioned correctly before soldering. 5
Soldering Steps (cont.) No. Description Illustration 4 Move soldering iron until tip is touching wire 5 Move solder wire to touch edge of the solder 6 Hold the soldering iron until solder melts on tip 7 Move solder in to form a small pocket 6
Soldering Steps cont. No. Description Illustration 8 Move soldering iron tip up. This will drag solder up with it. 9 Look for shiny fillets De-soldering steps: No. Description Illustration 1 Melt the solder with your iron. 2 Quickly position the solder sucker over the melted solder 7
De-soldering Steps cont. No. Description Illustration 3 Release the spring to suck up the solder 6.4 Class and Lab Activities Activity 1: Compare between soldering and de-soldering by completing the following table: Soldering De-soldering Definition Functions Required Tools 8
Activity 2: PCB drilling, mounting components and soldering. In your previous module, you have developed your PCB board. However, you didn't drill, mount, solder and test your PCB. In this activity, you will complete your PCB. 1. Using appropriate drill bits, drill the holes on your PCB for mounting the components 2. Mount the components in their corresponding direction 3. Solder each component on your PCB 4. Test the functionality of your circuit by switching on the switch and observe the LED behavior. 5. If your PCB doesn't function, investigate your soldering and PCB tracks. 9
6.5 Review Exercise Exercise 1: Define the following: Soldering: De-soldering: Exercise 2: What are the soldering functions? What are the de-soldering functions? Exercise 3: Match the tool with its usage Soldering iron Solder wire De-soldering pump Soldering iron stand Clamps Magnifying Glass Wet sponge A. Cleans the soldering tip from the solder B. Sucks the melted solder out of the joint C. provides heat to melt solder. D. helps to see tiny components leads E. an alloy made up of tin and lead. F. hold the PCB for support while soldering. G. is a heat resistant stand for the soldering iron. 10
Exercise 4: Write the name of each Tool: Tool Name 11