1
GATE EE 2014 Set 2
Numerical
+2
-0
The $$SCR$$ in the circuit shown has a latching current of $$40$$ $$mA.$$ A gate pulse of $$50$$ $$\mu s$$ is applied to the $$SCR$$. The maximum value of $$R$$ in $$\Omega$$ to ensure successful firing of the $$SCR$$ is ____________.
2
GATE EE 2013
+2
-0.6
Thyristor $$T$$ in the figure below is initially off and is triggered with a single pulse of width $$10\mu s.$$ It is given that $$L = \left( {{{100} \over \pi }} \right)\mu H$$ and $$C = \left( {{{100} \over \pi }} \right)\mu F.$$ Assuming latching and holding currents of the thyristor are both zero and the initial charge on $$C$$ is zero, $$T$$ conducts for
A
$$10\mu s$$
B
$$50$$ $$s$$
C
$$100\mu s$$
D
$$200\mu s$$
3
GATE EE 2009
+2
-0.6
Match the switch arrangements on the top row to be steady $$-$$ state $$V$$ - $$I$$ characteristics on the lower row. The steady state operating points are shown by large black dots.
A
$$A - i,\,\,B - ii,\,\,C - iii,\,\,D - iv$$
B
$$A - ii,\,\,B - iv,\,\,C - i,\,\,D - iii$$
C
$$A - iv,\,\,B - iii,\,\,C - i,\,\,D - ii$$
D
$$A - iv,\,\,B - iii,\,\,C - ii,\,\,D - i$$
4
GATE EE 2007
+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

A
$$4.7k\Omega$$
B
$$470k\Omega$$
C
$$47\Omega$$
D
$$4.7\Omega$$
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