**1.E**_{avg} = (2/π) * E_{max }= 0.636 * E_{max}

_{avg}= (2/π) * E

_{max }= 0.636 * E

_{max}

**2.E**_{rms} = {1/sq.root(2)} * E_{max }= 0.707 * E_{max}

_{rms}= {1/sq.root(2)} * E

_{max }= 0.707 * E

_{max}

**3.Form Factor = Rms Value / Avg. Value**

**4.Peak Factor = Maximum Value / Rms Value**

**5.I**_{rms} = {1/sq.root(2)} * I_{max} = 0.707 * I_{max}

_{rms}= {1/sq.root(2)} * I

_{max}= 0.707 * I

_{max}

**6.I**_{avg/mean} = (2/π) * I_{max} = 0.636 * I_{max}

_{avg/mean}= (2/π) * I

_{max}= 0.636 * I

_{max}

**7.Form Factor = 1.11 (for Sinusoidal Wave)**

**8.Peak Factor = 1.41 (for Sinusoidal Wave)**

**9.For Rectified Sine Wave(Half wave):**

**I**_{rms} = 0.5 * I_{max}

_{rms}= 0.5 * I

_{max}

**I**_{avg/mean} = (1/π) * I_{max} = 0.318 * I_{max}

_{avg/mean}= (1/π) * I

_{max}= 0.318 * I

_{max}

**Form Factor = 1.57**

**Peak Factor = 2**

**10.For Rectangular Wave**

**I**_{rms} = I_{max}

_{rms}= I

_{max}

**I**_{avg/mean} = I_{max}

_{avg/mean}= I

_{max}

**Form Factor = 1**

**Peak Factor = 1**

**11.For Triangular Wave:**

**I**_{rms} = I_{max} / sqr.root(3) = 0.578 * I_{max}

_{rms}= I

_{max}/ sqr.root(3) = 0.578 * I

_{max}

**I**_{avg/mean} = I_{max} / 2 = 0.5 * I_{max}

_{avg/mean}= I

_{max}/ 2 = 0.5 * I

_{max}

**Form Factor = 1.16**

**Peak Factor = 1.73**

**12.Power Factor = Resistance / Impedance = R/Z**

**13.Power Factor = Real Power / Apparent Power**

**14.DC supply will have Form Factor Infinity (∞)**

**15.Energy in Capacitor = 0.5 * C * V**^{2}

^{2}

**16.We need Amplifier and Feedback to get Oscillation. So these are the essential condition**

**17.X**_{L} = 2 * π * f * L (its unit is Ohm)

_{L}= 2 * π * f * L (its unit is Ohm)

**18.X**_{C} = 1 / (2 * π * f * C) (its unit is Ohm)

_{C}= 1 / (2 * π * f * C) (its unit is Ohm)

**19.The curve between current and frequency is resonance curve**

**20.At resonance (Series RLC), Power factor is Unity**

**21.Quality (Q factor) Factor is the Voltage magnification at resonance**

**22.For Parallel RLC resonance**

**23.Bandwidth = Resonance Frequency / Q-Factor**

__24.For a D.C Motor__ : :

__24.For a D.C Motor__: :

**V = E + I**_{a} . R_{a . . . . (i)}

_{a}. R

_{a . . . . (i)}

**T = k**_{a} . Φ . I_{a . . . . . (ii)}

_{a}. Φ . I

_{a . . . . . (ii)}

**E = k**_{n} . Φ . N . . . .(iii)

_{n}. Φ . N . . . .(iii)

**where V is the supply voltage to the motor.**

**E is the Back e.m.f of the motor.**

**I**_{a} is the Armature current.

_{a}is the Armature current.

**R**_{a} is the Armature resistance.

_{a}is the Armature resistance.

**T is the torque produced in the motor.**

**k**_{a} and k_{n }are the proportionality constant for Torque and Back e.m.f. respectively.

_{a}and k

_{n }are the proportionality constant for Torque and Back e.m.f. respectively.

**Φ is the flux.**

**N is the rotation speed (in rpm i.e. revolutions per minute).**

**Based on these formulae , a lot of numerical can be framed where the values of few parameters will be given and the other(s) needs to be found out.**

__using (ii) and (iii)__ we can have an *auxiliary formula* as:

*we can have an*

__using (ii) and (iii)__*auxiliary formula*as:

**T**_{1} . N_{1} = T_{2} . N_{2}

_{1}. N

_{1}= T

_{2}. N

_{2}

**where T**_{1 }is the torque at N_{1 }rpm and T_{2} is the torque at N_{2} rpm.

_{1 }is the torque at N

_{1 }rpm and T

_{2}is the torque at N

_{2}rpm.

**25. Series D.C. Generator ***cannot build up* on Open-circuit .

*cannot build up*on Open-circuit .

**26.Series Generator has the ***poorest* Voltage Regulation.

*poorest*Voltage Regulation.

**27.D.C. Generator **__Ideal__ has *ZERO(0)* Voltage Regulation.

__Ideal__has

*ZERO(0)*Voltage Regulation.

**28.D.C. Generator having ***negative Voltage Regulation* is for over compound type.

*negative Voltage Regulation*is for over compound type.

**29.Transformer Core ***decreases the reluctance* of the common magnetic circuits.

*decreases the reluctance*of the common magnetic circuits.

**30.DC Series motor : Φ ∝ I**_{a} , which means that as the armature current increases so does the flux.

_{a}, which means that as the armature current increases so does the flux.

**Hence, T = k**_{a} . I_{a}^{2} which is derived from point 1 equation (ii) [*look above*]

_{a}. I

_{a}

^{2}which is derived from point 1 equation (ii) [

*look above*]

**31.Transformer ***No Load test* helps us to find out the No load losses and magnetizing current in the transformer

*No Load test*helps us to find out the No load losses and magnetizing current in the transformer

**32.Transformer has*** lagging power factor* because of drawing magnetizing current for its working.

*lagging power factor*because of drawing magnetizing current for its working.

**33.Transformer cores are laminated in order to reduce eddy current losses.**

**Eddy current loss ∝ f**^{2} . k_{f}^{2} . B_{m}^{2} . t^{2} . V

^{2}. k

_{f}

^{2}. B

_{m}

^{2}. t

^{2}. V

**where, ***f is the* frequency of reversal of magnetic field ( Hz )

*f is the*frequency of reversal of magnetic field ( Hz )

*k*_{f }is the form constant.

*k*form constant.

_{f }is the*B*_{m }is the maximum value of flux density ( wb/m^{2 })

*B*maximum value of flux density ( wb/m

_{m }is the^{2 })

*t is the* thickness of lamination ( meter )

*t is the*thickness of lamination ( meter )

*V is the* volume of magnetic material ( m^{3 })

*V is the*volume of magnetic material ( m

^{3 })

# Note: The Informations are true to the best of my knowledge. Still if i have made any mistake while typing please let me know in the comment section so that i can correct it.