Govt. Exams
Entrance Exams
NAND gate is the complement of AND, so Y = (A.B)' where . represents AND operation.
XOR (Exclusive OR) produces 1 when inputs are different and 0 when they are same.
Binary 101 = 5 in decimal, so output line 5 is activated in a decoder.
To represent 15 states, we need n flip-flops such that 2^n ≥ 15. Since 2^4 = 16 ≥ 15, minimum 4 flip-flops are required.
Sequential circuits have memory elements (flip-flops) and their output depends on past inputs. Flip-flops are the basic sequential elements; multiplexers, encoders, and decoders are combinational circuits.
RAM (Random Access Memory) is volatile and loses all data when power is removed. ROM, EPROM, and Flash memory are non-volatile.
A T flip-flop toggles its output when T=1 and holds when T=0, making it ideal for frequency division and counter design.
A demultiplexer with n select lines has 2^n output lines. For 4 select lines: 2^4 = 16 output lines.
A multiplexer with n select lines can handle 2^n input lines. For 3 select lines: 2^3 = 8 input lines.
BCD (Binary Coded Decimal) requires 4 bits to represent decimal digits 0-9 (2^4 = 16 combinations, but only 10 are used).
