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    Dear ak__tevar 

Pageno 80 level 2 problems, 
(21)V= 10 sin (wt+30) 
I = 10 sin (wt-30) 
Instantaneous Power consumed in the circuit P(t) = V(t)I(t) 
Utilize expression for sin(A+B)sin(A-B). 
Double freq. terms yield zero average, leaving only 25W is the required power consumed in the circuit. 

(22)An ideal transformer 
(a) Is an abstract concept- since leakage and core losses cannot be zero. 

(b) One where the voltage and current relations are derived from Faraday’s law and Ampere’s law respectively – 
Current Relations 

closed line integral H.dl = N1Io (during no load condition) 

Since core flux does not change from no load to full load condition, 

closed line integral H.dl = N1I1+N2 I2 (during loaded condition) 

Consequently N1I1+N2 I2 = N1Io 
N1Io is small, therefore N1I1 -N2 I2 

Voltage relations, E = 4.44 f N m comes from Faraday’s law 

(c)Is characterized by a single parameter ratio n, the turns ratio which is evident from the equivalent circuit. 
Thus a, b, c are true and the correct option is D 

(28)Just before the completion of 2 sec, the inductor current is 8A (I = 4t; 0<t<2). Since the circuit does not have any resistor, the entire inductor energy is dissipated at the switching contacts during the with drawl of the 4V pulse. 
Hence current at t = 3s is zero. 

Author	Message
manju Senior Member Joined: 20Feb2007 Online Status: Offline Posts: 221	Topic: solution to ak_tevar problems Posted: 22Feb2007 at 3:49pm
	Dear ak__tevar Pageno 80 level 2 problems, (21)V= 10 sin (wt+30) I = 10 sin (wt-30) Instantaneous Power consumed in the circuit P(t) = V(t)I(t) Utilize expression for sin(A+B)sin(A-B). Double freq. terms yield zero average, leaving only 25W is the required power consumed in the circuit. (22)An ideal transformer (a) Is an abstract concept- since leakage and core losses cannot be zero. (b) One where the voltage and current relations are derived from Faraday’s law and Ampere’s law respectively – Current Relations closed line integral H.dl = N1Io (during no load condition) Since core flux does not change from no load to full load condition, closed line integral H.dl = N1I1+N2 I2 (during loaded condition) Consequently N1I1+N2 I2 = N1Io N1Io is small, therefore N1I1 -N2 I2 Voltage relations, E = 4.44 f N m comes from Faraday’s law (c)Is characterized by a single parameter ratio n, the turns ratio which is evident from the equivalent circuit. Thus a, b, c are true and the correct option is D (28)Just before the completion of 2 sec, the inductor current is 8A (I = 4t; 0<t<2). Since the circuit does not have any resistor, the entire inductor energy is dissipated at the switching contacts during the with drawl of the 4V pulse. Hence current at t = 3s is zero. Post Resume: Click here to Upload your Resume & Apply for Jobs

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