31.Write down the formula for a delta connected network is converted into a star network?
       
 

32. Write few advantages of sinusoidal waveform?
1. The response of the sinusoidal input for second order system is sinusoidal.

2. The wave form can be written in terms of sinusoidal function according to fourier theorem.

3. The derivatives and integral also sinusoidal.

4. Easy for analyses.

5. Easy to generate.

6. More useful in power industry.

Sufficient knock or pull these electrons from their position in the crystal and convert them in to
conduction electrons. Thus zener break down voltage decreases with temperature.

33. Distinguish between a cycle, time periods and frequency.
One complete set of positive and negative instantaneous values of the voltage or current is called cycle.
The time taken by an alternating quantity to complete one cycle is called time period (T).
Time period (T) =2 /W
The number of cycle that a alternating quantity completed per second is known as frequency. t is measured in HZ.
Frequency (f) = 1 / T

34. What is instantaneous value?
The value of an alternating current, at any particular moment is called its instantaneous value.

35. What are peak value and peak to peak value?
The peak value of the sine wave during positive or negative half only.
The sum of positive and negative value is called a peak to peak value. The peak to peak value of a sinusoidal alternating voltage is equal to two times the peak value.


36. What is average value?
The average value of the sine wave is the total area under the half-cycle curve divided by the distance of the curve.

37. Define effective value or RMS value of a sinusoidal voltage.
The R.M.S value may be determined by taking the mean of the squares of the Instantaneous value of current over one complete cycle. This is often known as the effective value.

38.Define phasor.
Graphical representation of phasors V = Vm <  and I=I < - known as phasor.

39.Define phase angle.
The angle between voltage and current is called phase angle. It is denoted by  .

40.What is impedance?
The ratio of the phasor voltage to the phasor current is called impedance.
Impedance (Z) = V/I

41.Obtain the equivalent impedance and reactances for series and parallel connections.

Impedance in series Zeq= Z1+Z2

Impedance in parallel Zeq= Z1 Z2/ Z1+Z2

Reactances in series jXeq = j (X1+X2)

Reactances in parallel j Xeq= j ( X1 X2/ X1+X2)

41. Define admittance.
The reciprocal of impedance is called admittance.It is denoted as Y and it is measured in siemens (S).
Admittance (Y) =1/Z =1/V

42. Obtain the equivalent admittance for series and parallel connections.

Admittance in series Yeq = Y1 Y2 /Y1+Y2

Admittance in parallel Yeq = Y1+Y2

43. Obtain the equivalent conductance and susceptance for series and parallel connections.

Conductance in series = G1 G2 /G1+G2

Conductance in parallel = G1+G2

Susceptance in series
jBeq = B1 B2 /G1+G2

Susceptance in parallel
jBeq= j(B1 B2)

44.Define phasor diagram.
The phasor diagram is a name given to a sketch in the complex plane showing the relationships of the phasor voltages and phasor currents throughout a specific circuit.