Electrical Engineering Aspect

 Series and Parallel Circuit:
1. Series Circuit:
A simple circuit or path of any complex circuit in which same current passes through all the elements in that path is called series circuit. The general circuit diagram of series circuit using resistors is as shown as follows. Series circuit have following features.
- Same current passes through all the element.
i.e. I₁ = I₂= …………………… = I_N = I
- Voltage divides in all the components. So, It is known as voltage divider circuit.
i.e. V = V₁+ V₂+ …………… + V_N

i.e. Voltage across ith component is,V_i = (R_i/n)× V = {R_i/R_eq}× V
- Equivalent resistance of series circuit is given by sum of all the components.R_eq = R₁+ R₂+ …………….. + R_N

Note : For multiple number of inductors in series:
L_eq = L₁+ L₂+ ……………………….. + L_N 

For multiple number of capacitors in series
- If one components failsin performing it’s operation in series circuit, it cause failure of overall circuit due to opening of single path.
2. Parallel circuit :
When potential different across any two paths or components is same, those two paths or components are said to be parallely connected. The general circuit diagram of parallel circuit is as shown as follows.
Parallel circuit have following features :
- Current divides through different element so it is known as current divider circuit. Current in ith component is given by,
- Applied voltage across each elements remains same.
i.e. V₁= V₂ = V₃ = ………………. = V_N
- Equivalent resistance of parallel circuit is given by the formula.
Note : For multiple number of inductors in parallel
For multiple number of capacitors in parallel
Ceq = C₁+ C₂+……………… + C_N
- If one component fails in performing its operation in parallel circuit, it does not cause failure of any other circuit operation.
 

2. Energy Resources
Energy Resources are classified as follows.
- Renewable & Non-Renewable Resources
Renewal Resources :
They are not depleted and available in long term in periodic basis.
a) Biomass : Different types of plant materials which contains stored energy that comes from sun are called biomass. e.g. Gobar gas, wood, coal etc.
b) Solar energy : It is the form of energy which applies energy from the sun in form of solar radiation. e.g. Solar power, photovoltaic output energy.
c) Wind Energy : It is conversion of wind energy into a useful form of energy. e.g. Wind turbine and generator Output in electrical power, wind mills output in mechanical power.
d) Hydropower : power generated from energy in water is hydropower. e.g. Hydroelectricity.
e) Geothermal Energy : Energy from thermal energy generated and stored in the core of earth.
f) Ocean & Tidal Energy : They are generally those forms which generate electricity from the tides in the ocean.
g) Biofuel : Energy derived from biological carbon fixation. e.g. Biomethanol, Biodiesel etc.
Non Renewal Resources :     
They are depleted with continuous use.
a) Fossil Fuel : Fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. E.g. Coal, Petrolium and natural gas.
b) Radioactive fuel/ Nuclear commercial Resources : Energy generated from nuclear reaction of radioactive material.
 

ii. Commercial and Non commercial Resources
Commercial Resources : They are useful for commercial processing purposes. e.g. Coal, Petrolium, Natural gas, Nuclear Energy, energy derived through thermo chemical and biochemical process etc.
Non commercial Resources : They are abundant in nature and are mostly used in rural area e.g. cowdung, charcoal, firewood, agricultural waste.

iii. Conventional and Non conventional Resources
Conventional Resources :
The sources of energy which have been in use for a long time. e.g. coal, petroleum, natural gas and water power.
Non conventional Resources :
The resources which are yet in the process of development over the past few years : e.g. solar, wind, tidal, biomass, biogas, geothermal.

3. Transformers :
- It is static electric machine which transfers electrical power from one circiut to another without changing frequency.
- It works on the principle of mutual induction.
- Parts of transformers.
a) Primary winding : Where input is given
b) Secondary winding : Where output is taken
c) Core : On which primary and secondary windings are wounded.
d) Yoke : Horizontal part of transformer core
e) Limb : Vertical part of transformer core
- It doesn’t work with DC source.
- Soft iron is used for making transformer core because of its high permeability.
- Transformation ratio (K) = N₂/N₁ = V₂/V₁ = I₁/I₂ 
a) If K = 1, N₁= N₂ (isolation transformer)
b) If K > 1, N₁< N₂ (step-up transformer)
c) If K < 1, N₁> N₂ (step-down transformer)
- Rms value of emf, induced in secondary winding is, E₂= 4.44fϕm
N₂
- Ideal transformer is that which has
a) No winding resistance
b) Core with infinite permeability
c) No coreloss and 100% efficiency.
- Eddy current is current circulating within core.
- Eddy loss α (I_eddy)².
- Copper loss in transformer is loss in winding resistance.
- During transformer operation, frequency remains constant.
- Core of transformer is laminated by varnish to reduce eddy current current loss.
- Capacity of transformer is measured KVA.
- Transformers are classified into three types according to utilities.

a) Power transformer :
• May be step-up or step-down (i.e. K >1 or K< 1).
• Rating is above 200 KVA.
• They are used at stations and substations.
b) Distribution transformer :
• They are step down (K<1).
• Used for consumer purposes.
• Rating upto 200 KVA.
c) Instrumental transformer :
• They are used for measurement purpose.
• CT (current transformer) is used to measure very high current.
• PT (potential transformer) is used to measure very high voltage.
 

4.Electrical Energy Generation
- It is based on the fundamental principles of electricity generation discovered by Michael Faraday.
- If Bm is maximum flux density, v is velocity of rotating coil, L is length of coil and ϕ is angle between axis of uniform magnetic field and axis of uniform magnetic field and axis of coil, magnetitude of induced emf is
E = BmLV sinϕ

Electricity Generation:
i. Convential methods of power Generation:
(They make use of prime mover for dividing electrical machines) e.g. Thermal, Hydro, Nuclear, Solar power generation etc.
ii. Non convential Methods of power Generation:
(They donot involve prime mover for power generation) e.g. solar cells, fuel cells, thermo electric generation etc.
 

Instrument In Electrical Measurement:
- Ammeter is used to measure current current through any element.
- Ideal ammeter has zero internal resistance.

- Ammeter is always connected in series with the element through which current is to be measured.
- Voltmeter is used to measure potential difference between two points of circuits.
- Voltameter is always connected in parallel with the element across which p.d. is to be measured.
- Ideal voltmeter has infinite resistance.
- Instrument voltmeter has infinite resistance.
- Instrument used to measure active electrical power is wattmeter i.e. It measures active power only i.e. VIcosφ.
 It has current coil which measures current (I) and voltage coil which measures p.d.(v) across  any element.