Paper Type : Whole Testpaper
Test Date : 20 May 2007
Test Location : Hyderabad
HAL PAPER ON MAY 20th AT HYDERABAD
1 synchro tc and rx is
a ) two phase ac
b) three phase ac
c) dc only
d) none
2 in 4 bit number one bit indicates sign of the number then the
locations are from
a) 8 to 8
b) 7 to 7
c) 16 to 16
d) None
3 G(s) = 10/S(S+2) then the natural frequency of this transfer function
is
a) 3.146
b) 4
c) 5
d) 2
4 In TV video amplifier is used for =?
5) one block contain one of the R L C element then the frequency of that
one is 1 MHZ when the capacitor C= 0.1 uf is added to that block then
the frequency becomes 2 MHZ then what is the element inside the block at
first time
a) resistor
b) inductor
c) capacitor with 0.5 uf
d) none of these
ans : b
6) For unit step input they gave the input G(S)=     ,h(s)=
then he ask the steady state error for that transfer fn
7)Avalanche photo diode is used when compared to PIN diode bcz
a) larger band width C)
b) high sensitivity d) 
8) some non zero DC voltage is to RC low pass circuit then the DC
voltage in the output contains
a) Same as in input
b) Higher than input
c) Zero
d) Slightly increases
9) ifthe output of the gate is always high then the gates applied to
this logic are
a) NAND and EXOR
b) Nand and NOR
c) AND and XNOR
d) OR and XOR
Ans ) a
10) For the voltage series feedback he gave input resistance and A and
beta value then find the output resistance ?
11)Signal to noise ratio =15 db Bandwidth =4KHZ then the channel
capacity ?
Ans : C= B Log (1+ s/n) =16 log 2
12 ) Four messages are given like this 0.5,0.25,0.125,0.125 ,entrophy
value is =?
Ans: Entrophy= Avg of all informations
13) Thermal Run away is not possible in FET bcz the flow of
a) minority careers c) _____
b) Transconductance d) none
Ans : FET is unipolar so there are no minority careers .Thermal run away
occurs only minority careers
14)Gm= 10 ,Rd =20k,Rl =10 find the amplification factor =?
Ans = U= Gm Rd
15) Two ideal voltage sourd=ces resistors are connected in series ,power
of that one is 4W ,If one of the sorce is active other resistors are
shorted .Calculate the power when both are active +/
a) 0W,8W
b) 8W,6W
c) 4W,0W
d) None
16) A TV braod cast tx uses which type of antenna =?
a) parabolic antenna b)=
c) d) 
ans : a
17) Electric field and equi potential lines are
a) parallel to each other
b) In Quadrature
ans : b
18 ) L1=  , L2 =  k= _ then mutual inductance of the coil
is =?
Ans : M=ksquare root of L!and L2
19 ) one cube some is there to find out the how many number of cubes are
having single side ?
20)Two qs in verbal are  two statements are given for that the
relation btwn those two
Totally there are 160 qs out of that 100 qs from technical and 60 qs
from aptitudeand verbal
By,
GVN Rao 

