SRM University 2007 B.Tech Electronics and Communications Engineering BANK : CUIRCUIT THEORY UNIT – IV - Question Paper

UNIT – IV

COUPLED CIRCUITS AND TUNED CIRCUITS

1. Define Self inductance and Mutual Inductance.

2. Two coupled coils with L1 = 0.02H L2=0.01 H and K=0.5 are connected in 4 various ways. Series aiding series opposing and parallel with both arrangements of the winding sense. elaborate the 4 equivalent inductance.

3. What is the maximum possible mutual inductance of 2 inductively coupled coils with self inductance.

4. In series fed doubly tuned transformer circuits both the primary and the secondary are tuned to the identical resonant angular frequency of 105 rad/sec. The maximum output voltage across the capacitor is 24 volts and is found by varying K If the inductance and the resistance of primary circuit are four µH and 0.1 ? resp. and the of the secondary circuit are 50 µH and one ? resp. compute the supply voltage.

5. In the single tuned resonant circuit , the applied voltage in a primary coil Eg = 20 V and R1=R2=5 ?, L1-L2=32MicroH, M=20 µH, C=(secondary side)=0.5 µF. Determine the resonant frequency and the output voltage at this frequency

6. Two coils connected in series have an equivalent inductance of 0.4H when connected in aiding and an equivalent inductance 0.2H when the connection is opposing. compute the mutual inductance of the coils

7. Two inductively coupled coils have self inductance L1= 40mH and L2=150mH. If the coefficient is 0.7 (i) obtain the value of mutual inductance ranging from the coils and (ii)the maximum possible mutual inductance.

8. The 2 coils connected in series have an equivalent inductance of 0.8 H when connected in aiding and an equivalent inductance of 0.5H when the connection is opposing. compute the mutual inductance.

9. Following data refers to 2 coupled coils one and two ?11 = 0.5m Wb , ?12 =0.3mWb, N1=100 turns and N2=500 turns, primary current is one A. obtain K , the inductance L1 and L2 and M.

10. Find the total inductance of the 3 series connected coupled coils where L1=1H , L2=2H, L3=5H, M12=0.5H M23=1H and M13=1H.

11 Find the expression for the mutual inductance in the series connection of 2 coupled coils, when the flux of the 2 coils assist every other, the net equivalent inductance being L1 and when the flux of the 2 coils oppose every other , the equivalent inductance being L2.


12. Two coupled coils have self inductance L1 =10mH and L2=20mH. The co-efficient of coupling (K) being 0.75 in the air. obtain the voltage in the 2nd coil and the flux of 1st coil given the 2nd coil 500 turns and the circuit current his provided by two sin 314 t A.

13. In an ideal transformer K = 0.8, the mutual inductance = 10H number of primary and Secondary turns are 50 and 200. find the value of primary current to produce 0.5wb flux to link secondary coil.

14. Show that in an ideal transformer the input impedance looking throw the primary terminals is the square of turns ratio times the secondary impedance.

Earning:   Approval pending.