1
GATE EE 2007
MCQ (Single Correct Answer)
+2
-0.6
A $$1:1$$ pulse transformer $$(PT)$$ is used to trigger the $$SCR$$ in the adjacent figure. The $$SCR$$ is rated at $$1.5$$ $$kV$$, $$250$$ $$A$$ with $${{\rm I}_L} = 250\,mA,\,\,{{\rm I}_H} = 150\,mA,$$ and $${{\rm I}_{G\max }} = 150mA$$ with $${{\rm I}_L} = 250\,mA,$$ $${{\rm I}_{G\min }} = 100mA.$$ The $$SCR$$ is connected to an inductive load, where $$L$$ $$=150$$ $$mH$$ in series with a small resistance and the supply voltage is $$200$$ $$V$$ $$dc.$$ The forward drops of all transistors/diodes and gate $$-$$ cathode junction during $$ON$$ state are $$1.0V$$

The minimum approximate volt $$-$$second rating of the pulse transformer suitable for triggering the $$SCR$$ should be: (Volt - second rating is the maximum of product of the voltage and the width of the pulse that may be applied)

A
$$2000\,\mu \,\,V - s$$
B
$$200\,\mu \,\,V - s$$
C
$$20\,\mu \,\,V - s$$
D
$$2\,\mu \,\,V - s$$
2
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
An $$SCR$$ having a turn ON time of $$5\,\,\mu \,\,\sec $$, latching current of $$50$$ $$mA$$ and holding current of $$40$$ $$mA$$ is triggered by a short duration pulse and is used in the circuit shown in figure The minimum pulse width required To turn the $$SCR$$ ON will be GATE EE 2006 Power Electronics - Power Semiconductor Devices Question 3 English
A
$$251\,\,\mu \,\,\sec $$
B
$$150\,\,\mu \,\,\sec $$
C
$$100\,\,\mu \,\,\sec $$
D
$$5\,\,\mu \,\,\sec $$
3
GATE EE 2005
MCQ (Single Correct Answer)
+2
-0.6
The figure shows the voltage across a power semiconductor device and the current through the device during a switching transition. Is the transition a turn ON transition or a turn OFF transition? What is the energy lost during the transition? GATE EE 2005 Power Electronics - Power Semiconductor Devices Question 10 English
A
Turn ON, $${{V{\rm I}} \over {2\left( {{t_1} + {t_2}} \right)}}$$
B
Turn OFF, $$V{\rm I}\left( {{t_1} + {t_2}} \right)$$
C
Turn ON, $$V{\rm I}\left( {{t_1} + {t_2}} \right)$$
D
Turn OFF, $${{V{\rm I}} \over {2\left( {{t_1} + {t_2}} \right)}}$$
4
GATE EE 2005
MCQ (Single Correct Answer)
+2
-0.6
An electronic switch $$S$$ is required to block voltages of either polarity during its OFF state as shown in figure (a). This switch is required to conduct in only one direction during its ON state as shown in the figure (b). GATE EE 2005 Power Electronics - Power Semiconductor Devices Question 9 English 1

Which of the following are valid realizations of the switch $$s$$?

GATE EE 2005 Power Electronics - Power Semiconductor Devices Question 9 English 2
A
Only $$1$$
B
$$1$$ and $$2$$
C
$$1$$ and $$3$$
D
$$3$$ and $$4$$
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