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 resistance $$R$$ should be

GATE EE 2007 Power Electronics - Power Semiconductor Devices Question 5 English
A
$$4.7k\Omega $$
B
$$470k\Omega $$
C
$$47\Omega $$
D
$$4.7\Omega $$
2
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
$$2\,\mu \,\,V - s$$
3
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
$$5\,\,\mu \,\,\sec $$
4
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, $${{V{\rm I}} \over {2\left( {{t_1} + {t_2}} \right)}}$$
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