POWER ELECTRONICS AND DRIVES PART 11

POWER ELECTRONICS AND DRIVES PART 11

1. For a transistor, the safe operating area (SOA) is a plot of
a) Ib versus Vce
b) Ib versus Ic
c) Ic versus Vce
d) Ic versus time
 

Answer: c

2. The forward safe operating area (FSOA) pertains to the operation when
a) the device is fired at a 50% Duty cycle
b) the device is forward-biased
c) the device is operated on AC
d) the device is operated on DC
 

Answer: b

3. The SOAs are plotted always on a _________ scale
a) time
b) frequency
c) logarithmic
d) polynomial
 

Answer: c
 
4. As the FSOA increases, the pulse width
a) decreases
b) increases
c) remains constant
d) vanishes
 

Answer: b

5. The SOAs provided by the manufacturers are for
a) single pulse operation & a particular temperature
b) multi pulse operation & all the temperature
c) all the conditions
d) a particular duty cycle operation
 

Answer: a

6. A device is operating at Ic = 4A & Vce = 50V. For the device to operate at Ic = 20A (Without damaging),
a) voltage should be increased
b) voltage should be reduced
c) voltage can be kept constant
d) current has to increased further
 

Answer: b

7. For a BJT, find the maximum power dissipation when the device is safely operated at Vce = 90V and Ic = 0.5A
a) 40 Watts
b) 35 Watts
c) 45 Watts
d) 30 Watts
 

Answer: c

8. The SOA for a MOSFET is plotted for
a) Id versus Vds
b) Ig versus Id
c) Ig versus Vds
d) Id versus Vgs
 

Answer: a

9. The SOA for an IGBT is plotted for
a) Ic versus Vge
b) Ig versus Ic
c) Ig versus Vce
d) Ic versus Vce
 

Answer: d

10. For MOSFET’s SOA, as the pulse width goes on increasing, the maximum voltage rating ____ & current rating ____
a) is constant, increases
b) increases, decreases
c) decreases, is constant
d) constant, decreases
 

Answer: c