basic workshop practice (electronics group) 17005
TRANSCRIPT
Basic Workshop Practice (Electronics Group) 17005
DEPARTMENT OF ELECTRONICS ENGINEERING.
Objective
The student will be able to:
• Read and interpret the drawing.
• Draw sketch for given job.
• Use specification tables.
• Decide Sequence of procedure.
• Recognize, identify and use of various tools used in soldering.
• Use of soldering technique for efficient repair work.
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Teaching & Examination Scheme:
Teaching Scheme Examination Scheme
TH TU PRPAPER
HRSTH PR OR TW TOTAL
-- -- 4 -- -- -- -- 50@ 50
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IDENTIFICATION OF ELECTRONIC COMPONENTS
ASSIGNMENT NO.01• Drawing of symbols / conventions of
components, devices, electromechanicalswitches, relays, Displays, connectors and cablesused in Electronics and Electrical engineering.
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Symbols / conventions of Wire
Sr.No. Symbol Component name Meaning
01Electrical Wire Conductor of
electrical current
02Connected Wires Connected
crossing
03Not Connected Wires
Wires are not connected
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
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Switches
Power Supply
Bulb
Symbols / conventions of Switches
Sr.No. Symbol Component name Meaning
01SPST Toggle Switch..\Switches\SPST.jpg
Disconnectscurrent whenopen
02SPDT Toggle Switch..\Switches\SPDT.jpg
Selects between two connections
03Pushbutton Switch(N.O)
Momentary switch - normally open
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Symbols / conventions of Switches
Sr.No. Symbol Component name Meaning
04Pushbutton Switch(N.C)..\Switches\Pushbutton Switch (N.O).jpg
Momentary switch - normally Closed
05DIP Switch..\Switches\DIP.jpg
DIP switch is used for onboard configuration
06SPST Relay Relay open / close
connection by an electromagnet
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ON
OFF
Symbols / conventions of Switches
Sr.No. Symbol Component name Meaning
07
SPDT Relay..\Switches\Relay.jpg
Relay open / close connection by an electromagnet
08Jumper Close connection
by jumper insertion on pins.
09Solder Bridge Solder to close
connection
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Symbols / conventions of Ground
Sr.No. Symbol Component name Meaning
01
Earth Ground Used for zero potential reference and electrical shock protection.
02Chassis Ground Connected to the
chassis of the circuit
03Digital / CommonGround
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Symbols / conventions of Resistor
Sr.No. Symbol Component name Meaning
01Resistor (IEEE) Resistor reduces
the current flow.
02Resistor (IEC)..\Switches\resistor-color-code-all.gif
03Potentiometer(IEEE)
Adjustable resistor - has 3 terminals.
04Potentiometer (IEC)..\Switches\Potentiometer.jpg
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Symbols / conventions of Resistor
Sr.No. Symbol Component name Meaning
05Rheostat (IEEE) Adjustable resistor
- has 2 terminals.
06Rheostat (IEC)..\Switches\Rheostat .jpg
07 Trimmer Resistor..\Switches\Trimmer Resistor.jpg
Preset resistor
08
Thermistor..\Switches\Thermistor.jpg
Thermal resistor -change resistance when temperature changes
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Symbols / conventions of Resistor
Sr.No. Symbol Component name Meaning
09
Photo resistor /Light dependentresistor (LDR)..\Switches\LDR 1.jpg
Photo-resistor -change resistance with light intensity change
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Symbols / conventions of Capacitor
Sr.No. Symbol Component name Meaning
01Capacitor Capacitor is used to
store electric charge. It acts as short circuit with AC and open circuit with DC.02
Capacitor
03Polarized Capacitor Electrolytic capacitor
04Polarized Capacitor
05Variable Capacitor..\Switches\Capacitor.JPG
Adjustable capacitance
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Symbols / conventions of Inductor
Sr.No. Symbol Component name Meaning
01Inductor Coil / solenoid that
generates magnetic field
02Iron Core Inductor Includes iron
03Variable Inductor..\Switches\Inductors.gif
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Symbols / conventions of Power Supply
Sr.No. Symbol Component name Meaning
01Voltage Source Generates
constant voltage
02AC Voltage Source AC voltage source
03Current Source Generates
constant current
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Symbols / conventions of Power SupplySr.No. Symbol Component name Meaning
04
Generator Electrical voltage is generated by mechanical rotation of the generator
05Battery Cell Generates constant
voltage
06
Controlled VoltageSource
Generates voltage as a function of voltage or current of other circuit element.
07
Controlled Current Source
Generates current as a function of voltage or current of other circuit element.2/6/2015 WPX ( 17005) 25
Symbols / conventions of Meter
Sr.No. Symbol Component name Meaning
01Voltmeter..\Switches\Voltmeter.jpg
Measures voltage. Has very high resistance. Connected in parallel
02
Ammeter..\Switches\Ammeter.jpg
Measures electric current. Has near zero resistance. Connected serially.
03Ohmmeter..\Switches\Ohmmeter.jpg
Measures resistance
04Wattmeter..\Switches\Wattmeter.jpg
Measures electric power
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Symbols / conventions of Lamp / Light Bulb
Sr.No. Symbol Component name Meaning
01
Lamp / light bulbGenerates light when current flows through
02
03
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Symbols / conventions of Diode
Sr.No. Symbol Component name Meaning
01
Diode Diode allows current flow in one direction only (left to right).
02
Zener Diode Allows current flow in one direction, but also can flow in the reverse direction when above breakdown voltage
03
Schottky Diode Schottky diode is a diode with low voltage drop
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Symbols / conventions of Diode
Sr.No. Symbol Component name Meaning
04Varactor / Varicap Diode
Variable capacitance diode
05Tunnel Diode
06Light Emitting Diode (LED)
LED emits light when current flows through
07Photodiode
..\Switches\Diode.gif
Photodiode allows current flow when exposed to light
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Symbols / conventions of Transistor
Sr.No. Symbol Component name Meaning
01NPN Bipolar Transistor Allows current flow
when high potential at base (middle)
02 PNP Bipolar Transistor
Allows current flow when low potential at base (middle)
03
Darlington Transistor Made from 2 bipolar transistors. Has total gain of the product of each gain.
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Symbols / conventions of Transistor
Sr.No. Symbol Component name Meaning
04JFET-N Transistor N-channel field
effect transistor
05 JFET-P TransistorP-channel field effect transistor
06
NMOS Transistor N-channel MOSFET transistor
07PMOS Transistor
..\Switches\transistorpinouts.gif
P-channel MOSFET transistor
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Symbols / conventions of Antenna
Sr.No. Symbol Component name Meaning
01Antenna / aerial
..\Switches\Antenna.jpg
Transmits & receives radio waves
02
03Dipole Antenna
..\Switches\Dipole Antenna.jpg
Two wires simple antenna
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Symbols / conventions of Misc.
Sr.No. Symbol Component name Meaning
01Motor..\Switches\Motor.jpg
Electric motor
02Transformer
..\Switches\Transformer.jpg
Change AC voltage from high to low or low to high.
03Electric bell..\Switches\Electric bell.jpg
Rings when activated
04Buzzer..\Switches\Buzzer.jpg
Produce buzzing sound
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Symbols / conventions of Misc.
Sr.No. Symbol Component name Meaning
05Fuse
..\Switches\Fuse.jpg
The fuse disconnects when current above threshold. Used to protect circuit from high currents.06
07Bus
..\Switches\Bus.jpg
Contains several wires. Usually for data / address.
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Symbols / conventions of Misc.
Sr.No. Symbol Component name Meaning
09Optocoupler / Opto-isolator
Optocoupler isolates connection to other board
10Loudspeaker
..\Switches\Loudspeaker.jpg
Converts electrical signal to sound waves
11Microphone Converts sound waves
to electrical signal
12Operational Amplifier..\Switches\OperationalAmplifier.jpg
Amplify input signal
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Symbols / conventions of Misc.
Sr.No. Symbol Component name Meaning
13Analog-to-digital converter (ADC)
Converts analog signal to digital numbers
14Digital-to-Analog converter (DAC)
Converts digital numbers to analog signal
15Crystal Oscillator
..\Switches\Crystal Oscillator.jpg
Used to generate precise frequency clock signal
16Schmitt Trigger Operates with
hysteresis to reduce noise.
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Symbols / conventions of Logic Gates
Sr.No. Symbol Component name Meaning
01OR Gate Outputs 1 when
any input is 1.
02AND Gate Outputs 1 when
both inputs are 1.
03NOT Gate (Inverter) Outputs 1 when
input is 0
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Symbols / conventions of Logic Gates
Sr.No. Symbol Component name Meaning
04NOR Gate Outputs 0 when
any input is 1.
05NAND Gate Outputs 0 when
both inputs are 1.
06XOR Gate Outputs 1 when
input is 0
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Symbols / conventions of Logic Gates
Sr.No. Symbol Component name Meaning
07D Flip-Flop Stores one bit of
data
08Multiplexer / Mux4 to 1
Connects the output to selected input line.
09Demultiplexer / Demux1 to 4
Connects selected output to the input line.
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IDENTIFICATION OF ELECTRONIC COMPONENTS
ASSIGNMENT NO.03• Collect the catalog from internet for instruments
required for Electronic Workshop.
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Instruments used in Electronic Workshop
• Function Generator.
• Multimeter.
– Analog Multimeter.
– Digital Multimeter.
• Power Supply.
– AC Power Supply
– DC Power Supply.
– SMPS.
– Programmable Power Supply.
• Oscilloscope.2/6/2015 WPX ( 17005) 41
Function Generator
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Analog Multimeter
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Digital Multimeter
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DC Power Supply
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Power Supply SMPS
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Oscilloscope
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Introduction and demonstration of soldering
WHAT IS SOLDERING
• Soldering is the process of joining metal leads, creating a mechanical and electrical bond. As shown in the figure, the lead of the resistor and the pad of the circuit board are mechanically attached and electrically connected.
WHAT IS REQUIRED
• The tools needed for the soldering process:
– Safety glasses
– Soldering iron
– Solder
– Wire cutter
– Damp sponge
TOOLS
Assemble the proper tools together.
WHY SAFETY GLASSES
• It is important always to wear thesafety glasses during the wholesoldering process to protect youreyes against boiling solder particlesthat fly up while the solder is meltingand pieces of leads that might fly inany direction when they are cut.
WHAT IS A SOLDERING IRON
• The soldering iron is the tool that is used to heat the joint. It has a tip that is heated by an internal heating element.
SOLDERING IRONS
Pencil tip Temperature Controlled
WHAT IS SOLDER
• Solder is the material that melts on the joint attaching to both the component
lead and the pad on the circuit board.
WHAT OCCURS WHEN SOLDER MELTS
• As the solder melts during the soldering process, it attaches to the component lead
and the pad.
• The flux flows into the joint dissolving existing oxides on the leads and preventing the formation of new ones. This facilitates the formation of a good soldering joint.
Step 1:
WHAT ARE THE STEPS IN SOLDERING?
Prepare component for mounting.
• In this step you bend the leads of thecomponent at 90 degree angle to fit into theholes of the circuit board. You can do thiswith your hand or with the help of pliers. Besure that the leads are bent at the rightdistance from the body of the component sothey fit comfortably in the holes on the board.
Step 2:
Mount component onto board
Mount component on board.
• In this step you insert the leads of the component into the holes on the board, from the component side. The body of the component should rest on the component side of the board.
• It is a common incorrect practice among new students toinstall the component on the soldering side (foil side) ofthe board instead of the component side, or to install thecomponent away from the surface of the board, insteadof resting on the surface of the board, as shown in thefigure.
Step 3:
Bend component leads slightly.
• After you have inserted the leads of thecomponent into the holes on the board, youshould bend the component leads slightly tohold the component in place while the boardis turned over to be soldered.
Step 4.
Heat iron. Clean tip with damp
sponge
Clean iron's tip.
• Before you start soldering and after the tip of the iron has heated up, the tip of the iron should be cleaned on a damp sponge and tinned, by melting apiece of solder on the iron's tip and then wiping the tip on the damp sponge again.
• The tip of the iron should always have an even shiny metal surface from the solder. Each time oxide forms on the tip, clean the tip on the damp sponge to make it shiny again.
Step 5.
Apply heat. • In this step you apply heat to the joint to be
soldered by touching the tip of the iron firmly against both the component lead, and the pad on the board, simultaneously. Allow about three seconds or more for the joint to heat up before applying the solder.
• This is one of the most important steps in thesoldering process. If you do not heat up the joint(lead and pad on the board) sufficiently you willget a cold soldering joint which will have to be re-soldered.
Step 6.
Apply Solder
Apply solder.
• After the joint has heated up, apply solder tothe point where the lead and the pad join.Apply enough solder to create a "mountain "of solder that attaches to both, the lead andthe pad, as shown in the drawing of step 8. Acommon problem among new students is toapply too little or too much solder, neither isgood.
Step 7.
Remove solder.
• After the solder has melted on the joint forming a nice connection as the one shown in steps 8 and 9, remove the solder wire from the joint then remove the iron.
Step 9:
Inspect the soldering joint. • After the joint has cooled off, visually inspect the
joint that you have created. It should have a shinyand smooth surface and it should attach to boththe component lead, and the pad on the board. Inthe next transparency we will see what good andbad soldering joints look like.
• If, during the inspection, you recognize that yoursoldering is not good, you will have to re-solderthe connection by reheating the joint with theiron, until the solder melts and then applying alittle more solder.
Step I0:
Cut excess lead
Cut off component leads.
• After you have soldered a joint the next step is to cut off the excess component lead using a wire cutter. Trim the lead off the component as close to the solder joint as possible. This is another important step in the assembly process that can not be avoided because untrimmed component
• leads might cause short circuits between metallic traces on the board.
Good solder joint.
As we have said before, a good soldering joint has a shiny and smooth surface and attaches to both the component lead, and the pad on the board.
Cold solder join: You can recognize a cold solderjoint because it is dull (not shiny) and irregular (notsmooth). Cold solder joints do not make good
electrical connections and should be re-solder.
Solder not attached to lead: In this type of defective soldering joint the solder is attached to the pad of the board but not to the lead of
the component.
In this type of defective soldering jointthe solder is attached to the lead ofthe component but not to the pad onthe board.
Solder not attached to pad
This problem is caused by nottrimming the component leads aftersoldering the joint.
Leads not trimmed
Leads not trimmed.
• Leads that are not trimmed pose a potential problem because they can be touching each other or touching other parts of the pad, producing short circuits and damaging the components. Never leave untrimmed leads after the soldering is completed.
Solder bridge:
• Solder bridge: A solder bridge is a bridge made with solder that is connecting two pads (or foil traces) that should not be connected. Sometimes solder bridges are easy to detect and other times they are so tiny that they can only be detected with the use of a magnifying glass.
Solder bridge:Solder bridges can be eliminated
by melting them with the soldering iron.