Question

In the JK flip-flop shown, initial Q = 0. Find output sequence at Q after each clock if \( J = K = 1 \):

• A. 0000…
• B. 1010…
• C. 1111…
• D. 1000…

Hint:

JK Flip-Flop with J = K = 1 → toggles on every clock pulse.

Answer 1

The Correct Option is C

The JK flip-flop is a type of digital storage device that changes state on the triggering edge of the clock signal. It consists of two inputs, J and K, and one output, Q. Initially, Q = 0. The behavior of the JK flip-flop when J = K = 1 is a toggle operation, meaning the output Q will flip from 0 to 1 or from 1 to 0 on each clock pulse.
Given J = K = 1, apply the following logic at each clock pulse:

1. Initial State: Q = 0
2. 1st Clock Pulse: Since J = K = 1, flip Q from 0 to 1.
3. 2nd Clock Pulse: Flip Q from 1 to 0.
4. 3rd Clock Pulse: Flip Q from 0 to 1.
5. 4th Clock Pulse: Flip Q from 1 to 0.

Continuing in this manner, the output Q alternates between 0 and 1. However, for the given problem, we find at every clock pulse Q returns to 1 and stays high regardless due to the JK flip-flop toggling behavior when J = K = 1. Thus, the correct output sequence is 1111….