Compare Lithium Battery and Lead Acid Battery

  

Lead Acid Battery & Lithium Battery

The comparison between lead acid battery and lithium battery is explained here.

Parameters	Lead – Acid Battery	Lithium Battery
Charging efficiency	Low – only 70%	Fast charging, it can be charged 50% in just 30 minutes

Inductor & Inductance

Inductor 

• If several number of turns are wound over the core, it is generally called as Inductor. 

• There are no power loss in the pure inductor. 
• The core of magnetic material has negligible loop area is used in order to make inductor. 

What is Solenoid? How does it work?

Solenoid Coil

• A coil of many circular turns of insulated copper wire wrapped closely in the shape of cylinder is called as solenoid. 
• The solenoid is a piece of equipment which generate magnetic fields.
• Figure show a long solenoid which is wound by number of turns. 
• The turns are closely wound and insulated with each other. The turns are wound in the form of helix.

Verification of Ohm's Law

 Apparatus

• DC Voltage Source : 1.0 V to 10.0 V
• Resistance 
• DC voltmeter : Suitable range
• DC ammeter : Suitable range
• Multimeter

In this theory, comparison between permanent magnet and electromagnet is given.

Compare: Permanent Magnet & Electromagnet

• Permanent Magnet is a magnet in which magnetism generated by the internal structure of material itself.
• Electromagnet is a magnet in which magnetic field is produced by an electrical current.

Ohm's Law

Statement of Ohm’s Law

• The current flowing through metallic conductor is directly proportional to potential difference across it, provided that the temperature and other physical conditions remains same. 
• If I is current passes through a conductor and V is potential difference across its terminal, according to ohm’s law

       I α V (constant temperature)

Resistors in Series and Parallel

In this theory, the difference between series connection and parallel connection of resistor is given.

Comparison Between Series & Parallel Connection of Resistors

Series connection of Resistors

Parallel connection of resistors

Power & Energy

In this theory, the concept of power, energy and kilo watt hour is given.

Power, Electrical Energy and Kilo Watt Hour

Power 

• It is defined as the rate of doing work.

                                  OR

• It is rate at which electrical energy is consumed or dissipated.

Joule Law

Joule Law Statement 

The heat generated in the conductor for a given time is directly proportional to

• Square of current passes through conductor for a given time
• Directly proportional to resistance for a given current and time
• Directly proportional to time for current flows through resistance  

Electrical Potential & Potential Difference

Electrical potential

• It is defined as the work done in bringing a unit positive charge from infinity to a particular point in the electric field.

      Electric field = work done / Electric charge

• The unit of work done is joule and charge is coulomb. 

Resistance & Resistivity

• The resistance of a particular metal / conductor depends upon its length, area and nature of material and temperature. 
• The resistance is directly proportional to length and inversely proportional to area.

       R α L

       R α 1 / a

Electric Current, Unit of Current

 

• The electrical current is defined as the rate of flow of charge in particular direction.

                                                   OR

• It is defined as the net flow of charge that passes through any cross-sectional area in a unit time.

What is Electrical Charge?

 

There are two types of electrical charge

• Positive charge
• Negative charge
• The charge carried by proton is positive charge whereas the charge carried by the electron is negative charge. 

Maintenance of Power Capacitor

 

The following points to be noted for maintenance of capacitor.

• Check tightness of connection periodically
• Use harmonics analyzer for analysis of harmonics due to non – linear load
• If non – linear load increase significantly, harmonic study is done
• If harmonics are present, de-tuned capacitor banks ( reactor ) must be considered

Protect capacitor against over load and short circuit

Use of HRC fuse or MCCBs for short circuit protection of capacitor

• The cable for short circuit protection should be selected such that it protects capacitor for 1.5 times the rated current. 
• The HRC fuse does not protect capacitor against over load, it is used only for short circuit protection. 
• The rating of HRC fuse should be 1.6 to 1.8 times that of rated capacitor current. HRC fuse does not use for switching of capacitor.

Bio Savart Law

The magnetic field strength at any point P due to incremental length dl carrying current is directly proportional to

• Length of incremental element
• Current carried by the element
• Sine of angle between line joining point P with length dl
• Inversely proportional to the square of distance of this point from the element
• Magnetic field strength

           dH α I dl Sin θ / r²

          dH = kI dl Sin θ / r²

         Where k is constant = ( 1 / 4π )

• This law is helpful to calculate field strength H due to current carrying conductor

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What is harmonics? Effect of harmonics

What is meant by voltage harmonics and current harmonics?

Types of smoothing reactor

Compare capacitor bank and Individual capacitor

Hot Armature Resistance

  

• Let us consider that the initial temperature or room temperature says 20 degree centigrade and final temperature of armature be 60 degree centigrade.

As

    R2 = R1 ( 1 + αt₀ )

Relation between Magnetic Flux density ( B ) and Magnetic Field Strength ( H )

 

Magnetic flux density ( B )

• It is defined as the magnetic flux per unit area of surface at right angle to the magnetic field. Its unit is weber per meter square

       B = Φ / A

Illumination System : Diffraction, Excitation, Emission, Glare and Incandescence

Electromagnetic Radiation

• It is defined as the emission / transfer of energy in the form of electromagnetic waves associated with photons

Diffraction

• It is defined as the deviation of the direction of propagation of radiation which is determined by radiation passes through obstacle.

Law of Magnetizing Force Between Two Magnetic Poles

Laws of Magnetizing Force

• Let us consider that the two magnet poles are placed in a medium. 
• The m₁ and m₂ is magnetic strength of the two poles, r is distance between them and µ is absolute permeability of the surrounding medium. The force ( F ) between them is