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Digital System Design

The truth table for an S-R flip-flop has how many VALID entries? A. 3 B. 1 C. 2 D. 4 Answer: A What is one disadvantage of an S-R flip-flop? A. It has no clock input B. It has no Enable input C. It has Race Condition D. It has only a single output. Answer: C How is a J-K flip-flop made to toggle? A.J = 0, K = 0 B.J = 1, K = 0 C.J = 0, K = 1 D.J = 1, K = 1 Answer: D Which of the following is correct for a positive level triggered D flip-flop? A. The output toggles if one of the inputs is held HIGH. B. Only one of the inputs can be HIGH at a time. C. The output complement follows the input when enabled. D. Q output follows the input D when the clock is HIGH. Answer: D What does the triangle on the clock input of a J-K flip-flop mean? A. Level enabled B. Edge-triggered C. Both Level & Edge triggered D. None of All. Answer: B A comparison between ring and johnson counters indicates that: A. A ring counter has fewer flip-flops but requires more decod...
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Digital Electronics MCQ

1. In which of the following base systems is 123 not a valid number? (a) Base 10 (b) Base 16 (c)Base8 (d) Base 3 Ans:d 2. Storage of 1 KB means the following number of bytes (a) 1000 (b)964 (c)1024 (d) 1064 Ans:c 3. What is the octal equivalent of the binary number: 10111101 (a)675 (b)275 (c) 572 (d) 573. Ans:b 4. Pick out the CORRECT statement: (a) In a positional number system, each symbol represents the same value irrespective of its position (b) The highest symbol in a position number system as a value equal to the number of symbols in the system (c) It is not always possible to find the exact binary (d) Each hexadecimal digit can be represented as a sequence of three binary symbols. Ans:c 5.The binary code of (21.125)10 is (a) 10101.001 (b) 10100.001 (c) 10101.010 (d) 10100.111. Ans:a 6.A NAND gate is called a universal logic element because (a) it is used by everybody (b) any logic function can be r...
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Power Electronics MCQ

1. What is holding current in SCR? It is the minimum current required to hold the SCR in forward conduction state. When the forward current becomes less than holding current, SCR turns from forward conduction state to forward blocking state. 2. What is latching current in SCR? It is the minimum current required to latch(turn on) the SCR from forward blocking state to forward conduction state. 3. What are the different turn on methods of SCR? Forward voltage triggering Gate Triggering dv/dt triggering Temperature triggering Light triggering 4. What is snubber circuit? The snubber circuit is used for the dv/dt protection of the SCR. It is a series combination of a resistor and a capacitor in parallel with the SCR. 5. What is hard switching of the thyristor? When gate current is several times higher than the required gate current, the SCR is said to be hard fired. It reduces the turn ON time and enhances the di/dt capability. 6. What is firing...
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