Question

Which of the following is a universal flip-flop ?

• A. S-R flip-flop
• B. J-K flip-flop
• C. D flip-flop
• D. T flip-flop

Hint:

JK flip-flop is called universal because it can be configured to work as SR, D, and T flip-flops.

Answer 1

The Correct Option is B

Concept: A universal flip-flop is one that can perform the operations of other flip-flops by suitable input connections. Among all flip-flops: \[ \text{J-K flip-flop} \] is considered universal.

Step 1: Understand JK flip-flop operation. The JK flip-flop has two inputs: \[ J,\ K \] It eliminates the invalid state present in SR flip-flop. Its truth table allows:
• Set
• Reset
• Toggle
• No change

Step 2: Why it is universal. By suitable input combinations, JK flip-flop can behave like:
• SR flip-flop
• D flip-flop
• T flip-flop Hence it is called: \[ \text{Universal flip-flop} \]

Step 3: Analyze other options. SR flip-flop Has invalid condition: \[ S=R=1 \] Thus not universal. D flip-flop Used mainly for data storage. T flip-flop Mainly used for toggling and counters.

Step 4: Write final answer. Therefore the correct answer is: \[ \boxed{\text{J-K flip-flop}} \]