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MECHATRONICS TECHNICIAN
Tailored By
Obaid ur Rehman ™

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Module A: Maintain Electrical System
Task A1 : Maintain electrical system installation
of mechatronics system

4. Interpret electrical drawing / manual
• Symbols
• Legends
• Technique to Interpret (Right or Left / Up or Down/ Source or
Output) Where to Start ?.
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19. Electrical Quantities
100.2 -The Three main Electrical Quantities are
– Voltage
– Current
– Resistance
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20. Voltage
The force which tends the electron to flow is termed as voltage. The unit
voltage is volts. Voltage must always be measured in parallel, across the
electrical load with instrument Voltmeter.
Current
The flow of electrons in called current. The flow of electrons is due to the
certain potential difference between two conductors. The unit of current is
Ampere. It must be measured in Series with the electrical circuit or load
with the instrument Ammeter.
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21. Resistance
The opposition to the flow of current is termed as resistance. The resistance must
be measured when the circuit is isolated from the major source. The unit of
resistance is ohms Ω.The instrument need to measure resistance is
ohmmeter.
All these electrical values can be measure through an instrument
“Multimeter”
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22. 100.3 Differentiate Alternating and Direct current
Types and Sources of Supply
There are only two types of electricity supply, direct current (D.C) and alternating
current (A.C), D.C is obtained from cells and batteries, D.C generators or
electronically derived from A.C (rectification), A.C is obtained from A.C
generators.
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23. C Comparison Chart3/15/2016 23

24. 100.4 Identification of Electrical tools
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25. 100.5 Use test and measuring Instrument
• Tests and measurements are important in designing, evaluating, maintaining
and servicing electrical circuits and equipment.
• In order to detect electrical quantities such as current, voltage, resistance or
power, it is necessary to transform an electrical quantity or condition into a
visible indication.
• This is done with the aid of instruments (or meters) that indicate the
magnitude of quantities either by the position of a pointer moving over a
graduated scale (called an analogue instrument) or in the form of a decimal
number (called a digital instrument).
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26. Multimeter
• A multimeter is a devise used to measure voltage, resistance and current
in electronics & electrical equipment
• It is also used to test continuity between to 2 points to verify if there is
any breaks in circuit or line
• There are two types of multimeter Analog & Digital
– Analog has a needle style gauge
– Digital has a LCD display
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27. There are 2 styles of multimeters.
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28. Meter leads
 Red meter lead Is connected to Voltage/Resistance or amperage port Is
considered the positive connection.
 Probes Are the handles used to hold tip on the tested connection.
 Tips Are at the end of the probe and provides a connection point.
 Black meter lead Is always connected to the common port Is considered the
negative connection.
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29. Display & Dial Settings
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Common DMM Symbols
These symbols are often found on multimeter and schematics. They are
designed to symbolize components and reference values.

31. Measuring Voltage
• Voltage (V) is the unit of electrical pressure; one volt is the potential difference needed
to cause one amp of current to pass through one ohm of resistance
• Voltage is broke up into 2 sections AC & DC Alternating Current (AC) is house voltage
(220vac) Direct Current (DC) is battery voltage (12vdc)
• On switched meters use one value higher than your expected value
• Be very careful to not touch any other electronic components within the equipment and
do not touch the tips to each other while connected to anything else
• To measure voltage connect the leads in parallel between the two points where the
measurement is to be made. The multimeter provides a parallel pathway so it needs to
be of a high resistance to allow as little current flow through it as possible.
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33. Measuring Resistance and Continuity
• Resistance (Ω) is the opposition to current
• Resistance is measured in Ohm's
• Disconnect power source before testing
• Remove component or part from system before testing
• Measure using lowest value, if OL move to next level
• Testing for continuity is used to test to verify if a circuit, wire or
fuse is complete with no open Audible continuity allows an alarm
if circuit is complete
• If there is no audible alarm resistance of 1 ohm to 0 .1ohm should
be present
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35. Measuring Current
• Current (amps) is the flow of electrical charge though a
component or conductor
• Current is measured in amps or amperes
• Disconnect power source before testing
• Disconnect completed circuit at end of circuit
• Place multimeter in series with circuit
• Reconnect power source and turn ON
• Select highest current setting and work your way down.
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37. Review
• A meter capable of checking for voltage, current, and resistance is called a multimeter,
• When measuring Voltage the multimeter must be connected to two points in a circuit in
order to obtain a good reading. Be careful not to touch the bare probe tips together
while measuring voltage, as this will create a short-circuit!
• Never read Resistance or test for Continuity with a multimeter on a circuit that is
energized.
• When measuring Current the multimeter must be connected in a circuit so the electrons
have to flow through the meter
• Multimeters have practically no resistance between their leads. This is intended to allow
electrons to flow through the meter with the least possible difficulty. If this were not the
case, the meter would add extra resistance in the circuit, thereby affecting the current.
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38. 100.6 Calculate electrical quantities in circuits
• Voltage
• Current
• Resistance
• Power
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Formulas
Voltage V = IR
Resistance R = V/I
Current = V/R Power – P = VI
P = I2R
P = V2R

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42. 100.7 Interpret Electrical Component Specifications
The general electrical component specifications are based on voltage and current
rating emphasize by the manufacturer for the optimum utilization , safety of
device and devices associated with the component.
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45. Activity
• Find an Electrical/Electronic Component in the Mechatronics System.
• Translate there specifications in terms of
• Rating Voltage
• Rating Current
• Etc.
• Mention the role and characteristics of a Component for the Mechatronics
System
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46. Characteristics and Terminology
• Breakdown Voltage
The maximum tolerated voltage by the relay for a specified time period without damaging the relay.
• Coil Current
The nominal current that flows when nominal voltage is applied to coil.
• Coil Resistance
The electrical resistance across the coil wire.
• Coil Voltage
The nominal voltage necessary for the coil current to flow.
Contact Bounce Time
• The elapsed time between from the initial to the final closing or opening of a contact. It is
typically shorter than 5 ms.
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47. Characteristics and Terminology
• Contact Rating
The amount of voltage/current that can be handled by the contacts for nominal operation.
• Contact Resistance
The electrical resistance across the closed contacts.
• Drop Out Current/Voltage
The amount of current/voltage at or above which the relay must deenergize and move the armature
back to its initial position.
• Electrical Life
The minimum number of times the relay can be operated under nominal conditions (temperature,
humidity, etc.) with a specific load being switched by the contacts.
• Mechanical Life
The minimum number of times the relay can be operated under nominal conditions (temperature,
humidity, etc.) with no load on the contacts.
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48. Characteristics and Terminology
• Pick Up Current/Voltage
The amount of current/voltage at or below which the coil must energize and move the armature. It is
typically around 75% to 85% of the nominal current/voltage.
• Release Time
The time from the initial removal of coil power to the moment the armature returns to its
deenergized position, either making or breaking contacts (depending on switch type). This does not
include bounce time.
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49. 100.8 Describe necessity of earthing system.
• Earthing
Earthing is the connection of the exposed conductive parts of an electrical
installation to the main protective earthing terminal of the installation.
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50. • Exposed conductive parts
Are the metalwork of the electrical installation. The conduit, trunking, metal boxes
and equipment that make up the electrical installation.
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51. • Extraneous conductive parts
A conductive part liable to introduce a potential, generally earth potential, and not
forming part of the electrical installation. The structural steelwork of the building,
gas, water and central heating pipes and radiators.
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52. 100.9 State characteristics of semi-conductor components and
circuits
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53. Semi-Conductor
• Semi-conductor is composed of two words-Semi and Conductor. Semi
means not completely while conductor mean something, which can
conduct electricity.
• Semiconductors are group 4 elements, which means they have four
valence electrons For this reason they are also known as tetravalent
elements.
• These group elements are Carbon (C) , Silicon (Si) , Germanium (Ge)
and tin (Sn) of these only Silicon and Germanium are used as Intrinsic
Semiconductors.
• Silicon and Germanium possess the resistivity 2.3 x 103 Ω m and
0.45 Ω m
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54. Doping
• Adding extremely small amounts of impurities to pure semiconductors
in a controlled manner is called doping.
• In order to improve their conduction very small quantities (in the order
of 1 part in 105 to 1 part in 108 ) of certain other elements are added.
• The impurity elements that are added are either pentavalent (have five
valence electrons) or are trivalent (have three valence electrons) atoms.
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55. Types of Semi Conductor
N-Type
• Antimony, arsenic and phosphorus are called n-type impurities and
form an n-type material when any of these impurities are added to
silicon or germanium.
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56. Conduction in N-Type Material
• Arsenic, antimony and phosphorus have five valency electrons.
• The ‘fifth’ valency electron is not rigidly bonded and is free to conduct, the
impurity atom donating a charge carrier.
• A two-dimensional diagram depicting this in which a phosphorus atom has
replaced one of the germanium atoms. The resulting material is called n-type
material, and contains free electrons.
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57. Types of Semi Conductor
P –Type
• Indium, aluminium and boron are called p-type impurities and form
a p-type material when any of these impurities are added to a
semiconductor.
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58. Conduction in P-Type Material
• Indium, Aluminium and boron have three valency electrons.
• One of the four bonds associated with the semiconductor material is deficient
by one electron and this deficiency is called a hole. Holes give rise to
conduction when a potential difference exists across the semiconductor
material.
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DIODE
• A diode is so called because it has two terminals: the anode, which is
the positive terminal, and the cathode, which is the negative terminal.
• In the case of a p-n junction diode the anode is the p-type and the
cathode is the n-type.
• A diode will conduct in one direction but not in the other.

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Transistor
• The bipolar junction transistor consists of three regions of semiconductor
material. One type is called a p-n-p transistor, in which two regions material
sandwich a very thin layer of n-type material. Of p-type
• A second type is called an n-p-n transistor, in which two regions of n-type
material sandwich a very thin layer of p-type material.

61. 100.10 Identify current path in D.C power supplies
Current Path in D.C Power Supplies
• A direct current (DC) circuit is a circuit is which the current through each
branch in the circuit is always in the same direction.
• When the power supply is steady in time, and then the circuit is a purely
resistive network then the current in each branch will be steady, that is the
currents will not vary in time.
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62. 100.11 State characteristics of analogue and digital electronic
circuits
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63. Signal
A signal is any kind of physical quantity that conveys information.
• Audible speech is certainly a kind of signal, as it conveys the thoughts
(information) of one person to another through the physical medium of
sound.
• Hand gestures are signals, too, conveying information.
• This text is another kind of signal, interpreted by your English-trained
mind as information about electric circuits.
The word signal will be used primarily in reference to an electrical quantity of
voltage or current that is used to represent or signify some other physical
quantity .
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64. Analog Signal
• An Analog Signal is a kind of signal that is continuously variable, as opposed to having a
limited number of steps along its range (called digital).
• A well-known example of analog vs. digital is that of clocks.
• In the early days of industrial instrumentation, compressed air was used as a signaling
medium to convey information from measuring instruments to indicating and controlling
devices located remotely.
• A pneumatic (air signal) level "transmitter" device set up to measure height of water (the
"process variable") in a storage tank would output a low air pressure when the tank was
empty, a medium pressure when the tank was partially full, and a high pressure when the
tank was completely full.
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65. Digital Signal
• Digital Signals are based 0 and 1 level.
• Digital Clock is an example of it.
• The signal you send to your TV to change channels
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