Table of Content
Electrical safety
- Safety practice – first aid
- Electric shock
- Effects of electric shock
- Treatment of electric shock
- Electric burns
- Burns and scalds
- Severe bleeding
- Immediate action
- To control severe bleeding
- Large wound
Basic hand tools – screwdrivers, pliers and tweezers
- Basic hand tools
- Screwdrivers
- Length of blade L and width of tip W
- Straight wings and tapered wings
- Instrument screwdrivers
- Impact screwdrivers
- Special types of screwdrivers
- Using a screwdrivers
- Pliers
- Diagonal cutter plier
- End cutting plier
- Flat nose pliers
- Round nose pliers
- Long nose pliers
- Combination pliers
- Circlip pliers for external circlip
- Circlip pliers for internal circlips
- Pliers used by electrician
- Tweezers
Joints in electrical conductors
- Definition of joints
- Types of joints
- Pig-tail/rat p tail/twisted joint
- tee joint
- Britannia joint
- Britannia tee joint
- Western union joint
- scarfed joint
- Plain tap joint
- Aerial tap joint
- Knotted tap joint
- Duplex cross-tap joint
- Double-cross tap joint
Electrical soldering practice
- what is soldering?
- Necessity of soldering
- Solder used for copper
- Factors influencing the choice of a solder
- Flux
- General Properties of flux
- Soldering methods
- Soldering with a soldering iron
- Soldering with a soldering gun
- Soldering with a flame
- Dip soldering
- Techniques of soldering
- Soldering with electric soldering iron
- The electric soldering iron
- The bit
- Selecting the bit
- Care of the bit
- Dressing the bit
- Cleaning the bit
- Wetting (soldering)
- Techniques of soldering
- Tinning the soldering iron
- Cleaning the surface to be soldered
- Applying the flux
- Applying the solder
- Safety
- Soldering with pot and ladle
- Reconditioning of solder which is subjected to repeated melting
- Soldering Aluminium cables
- Soldiering od Aluminium cables
- Solder
- Flux
- Procedure Of soldering Aluminium
- Precaution to be followed while soldering Aluminium
- Safety
Types of current
- Types of electric supply
- DC supply
- Types of current
- AC supply
- Alternating voltage
- Identification of instrument from the data given on the dial
- Data contained on the measuring instrument dial
- Measuring range and measuring units
- Types of current
- Testing potential
- Using position
- Accuracy class
- Measuring instrument types
- Indication error
- Terminal markings
- Reading instrument scales
- Classification of instrument as per accuracy
- Readingaccuracy
- Indicators
- Mirror scales
- Zero adjustment
- Types of scales
- Coarse and coarse-fine scale
- Fine scale
- Extended scale
- Linear scale
- Non-linear scale
- Sources of errors when measuring
- Device errors
- Influence errors
- Switching errors
- Human errors
- Reading the scales
- Precaution to be observed while using an instrument
- Introduction of electricity – Ohm’s Law
- Introduction
- Simple electric circuit
- Open circuit
- Short circuit
- Electric current
- Si unit of electric charge
- Electromotive force
- Potential difference
- Resistance
- Ohm’s law
- Application of ohm’s law
- Ohm’s law verification
- Power and energy in simple electrical circuit
Multimeter
- Types of multimeters
- Multimeter as a DC voltmeter
- Multimeter as a DC ammeter
- Multimeter as an ohmmeter
- Multimeter as a AC voltmeter
- Methods of measuring DC voltages
- Method of measuring AC voltages
- Method of measuring direct current
- Method of measuring resistance
- Method of use
- Application of a multimeter
- Types of a multimeter
- Analogue types
- Digital types
- Comparison of analogue and digital multimeter
- DMM functions
- DMM displays
- Multimeter- safety precautions
Measuring voltage and current using multimeter
- Multi-range meters
- Meter scales of multi-range meter
- Identifying the scale tro take readings
- Multimeter as DC VOLTMETER
- Multimeter as DC AMMETER
- Multimeter as AC VOLTMETER
- Multimeter as AC AMMETER
- Multi-meter as OHMMETER
- Resistance zero setting
Dynamically induced EMF
- Generator
- Principle of the generator
- Faraday’s laws of electromagnetic induction
- Types of emf
- Dynamically induced emf
- Statically induced emf
- Production of dynamically induced emf
- Systems of connection in 3-phase AC
- Methods of 3-phase connection
- Star connection
- Delta connection
Parts of a DC generator and their functions
- DC motor – principle and types
- Introduction
- Principles of a DC motor
Applications of a DC series motor, shunt motor, compound motor
- Uses of a DC series motor
- Application of DC shunt motor
- DC compound motor
- Application of DC differential compound motor
Single phase motors – types – resistance/induction-start, induction-run motor
- Working of split-phase motor
- Application of resistance-start, induction-run motor
- Induction-start, induction-run motor
- Capacitor-start, induction-run motor
- Application
- Capacitors used in single phase capacitor motors
- Capacitor-start, capacitor-run motor
- Permanent capacitor motor
- Capacitor-start, capacitor-run motors
- Application
Transformers
- Two- winding transformers
- Auto transformers
- Principle
- Application
Secondary cell (lead acid)
- Secondary cell
- Terms and definitions
- Electrolyte
- Electrodes
- Anode
- Electrolysis
- Electrochemical equivalent
- Coulomb
- Faraday’s laws of electrolysis
- First law
- Second law
- Types of secondary cells
- Lead acid cell
- Charging secondary battery
- Necessity of charging
- Batterycharger
- Charging current
- Secondary cell/battery – care & maintenance
- Care and maintenance of batteries
- Precautions
Identifying, checking, finding value of fixed resistor
- Resistors
- Units of resistance
- Classification of resistors
- Fixed value resistors
- Construction
- Power rating
- Resistors values- coding schemes
- Colour band coding of resistors
- Tolerance
- Typo graphical coding of resistors
- Application
- Measuring ohmic value of resistors
- Wire-wound resistors
- Construction
- Resistor values
- Applications
- Other types of resistors
- Special types of fixed value wound resistors
- Resistors lead bending
- Types of resistor leads
- Identifying, checking and finding value capacitors
- Capacitor action of storing charge
- Unit of Capacitance
- SOLUTION
- Factors that determine the value of capacitance
- Working voltage or voltage rating of capacitor
- Function of a dielectric in a capacitor
- Types of capacitors
- 1 Fixed value capacitors
- 2 Variable capacitors
- Specifications of capacitors
- Types of capacitor
- Capacitance Value
- DC working voltage rating (DCWV)
- Tolerance
- Temperature coefficient
Testing of Capacitors
- CONSTRUTIN OF CAPACITORS
- COMMON DEFECTS IN ACITORS
- Short circuited capacitors
- Open capacitors
- Leaky capacitors/ leakage resistance
- Checking capacitors
- Capacitor action – normal resistance test
- Charging – holding test on capacitors
Identification of Rectifier Diodes
- SEMICONDUCTORS
- Semiconductor theory
- Intrinisc semiconductors
- Extrinisc semiconductor
- N- type semiconductor
- P- type semiconductor
- P- type material
- P- N junction
- Type of diodes
- Classification of Diodes
- Point contact diodes
- Junction diodes
- Type of Diodes packaging
- Testing rectifier diodes using ohmmeter
- Polarity marking on the diodes
- Type number or diode code number
Construct and test a bridge Rectifier
- Important specification of a diodes
- The JEDEC type code
- The PRO- ELECTRON type code
- The JIS type code
- Diode equivalents
- AC- to – DC conversion using diode – Half wave rectifier
- RECTIFICATION
- Calculation output DC level in half – wave rectifiers
- Ripple frequency
- Peak inverse voltage voltage
- Full wave rectifiers
- OutputDClevel in a two – diode full wave rectifier
- Ripple frequency in a full wave rectifier
- Peak inverse voltage
- Current rating of diode in a full wave rectifier
- Disadvantages of TWO DIODE full wave rectifier
- The Bridge Rectifier
- Output Dc level in a bridge rectifier
- Ripple frequency – Bridge rectifier
- Peak inverse voltage – Bridge rectifier
- Current rating of diodes in bridge rectifier
- Encapsulated bridge rectifier module
Identification and checking Transistors
- INTRODCTION TO TRANSISTORS
- CLASSIFICATION OF TRANSISTORS
- 1 Based on the semiconductor used
- 2 Based on the P and N junctions are organized as shown in Fig 5
- 3 Based on the power handling capacity of transis - tors as shown in Table below (Fig 6 )
- 4 Based on the frequency of application
- 5 Based on the manufacturing method
- 6 Based on the type of final packaging
- 1 Junction test
- 2 Quick turn-ON test
Temperature and pressure controls
- Types of pressure controls
- Purpose of the bellow type low pressure switch
- Liquid line solenoid valve
- The use, installation and set point of electronic thermostat ( Controller)
- Indicators leads
- Programming
- Parameter Programming
- Resistance temperature detector (RTD)
- Description of the parameters
Electrical components
- Deforst Timer
- Clocks or timer
- Defrost Heater
- PTC relay
- Staring Relay
- Current ( magnetic ) relay
- Solid state relay
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