LG Previous Years Solved Sample Placement Papers
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'In a 4-bit R/2R ladder digital-to-analog converter, because of negative feedback, the operational amplifier keeps the inverting (minus) input near ________.'
a) 5 volts
b) zero volts
c) a voltage determined by the binary weighted input
d) none of the above
Ans: b) zero volts -
'Why is the given circuit called an inverter?'
a) The output is the opposite (inverse) of the input.
b) The output is in phase with the input.
c) The output is the same as the input.
d) There is no output.
Ans: a) The output is the opposite (inverse) of the input. -
'The hexadecimal number 4B16 is transmitted as an 8-bit word in parallel. What is the time required for this transmission if the clock frequency is 2.25 MHz?'
a) 444 ns
b) 444 s
c) 3.55 s
d) 3.55 ms
Ans: a) 444 ns -
'List which pins need to be connected together on a 7493 to make a MOD-12 counter.'
a) 12 to 1, 11 to 3, 9 to 2
b) 12 to 1, 11 to 3, 12 to 2
c) 12 to 1, 11 to 3, 8 to 2
d) 12 to 1, 11 to 3, 1 to 2
Ans: c) 12 to 1, 11 to 3, 8 to 2 -
'In a TTL circuit, if an excessive number of load gate inputs are connected, ________.'
a) VOH(min) drops below VOH
b) VOH drops below VOH(min)
c) VOH exceeds VOH(min)
d) VOH and VOH(min) are unaffected
Ans: b) VOH drops below VOH(min) -
'The internal RAM memory of the 8051 is:'
a) 32 bytes
b) 64 bytes
c) 128 bytes
d) 256 bytes
Ans: c) 128 bytes -
'Which of the following commands will move the number 27H into the accumulator? (8051)'
a) MOV A, P27
b) MOV A, #27H
c) MOV A, 27H
d) MOV A, @27
Ans: b) MOV A, #27H -
'An alternate function of port pin P3.0 (RXD) in the 8051 is:'
a) serial port input
b) serial port output
c) memory write strobe
d) memory read strobe
Ans: a) serial port input -
'In an 8051 program, DA A adjusts the value in the accumulator resulting from an addition into two BCDs.'
a) True
b) False
Ans: a) True