Question

Consider a 3-bit counter, designed using T flip-flops, as shown below. Assuming the initial state of the counter given by $PQR$ as $000$, what are the next three states? 

• A. 011, 101, 000
• B. 001, 010, 111
• C. 011, 101, 111
• D. 001, 010, 000

Hint:

In T flip-flop counters, always examine the toggle conditions carefully instead of assuming a standard binary count sequence.

Answer 1

The Correct Option is A

Step 1: Recall the operation of a T flip-flop.
A T flip-flop toggles its output when $T = 1$ and holds its state when $T = 0$.

Step 2: Analyse the given counter circuit.
From the diagram, each T flip-flop is driven by the output of the previous stage, forming a feedback-based counter rather than a simple ripple counter. The toggle conditions depend on the current states of $P$, $Q$, and $R$.

Step 3: Determine the state transitions.
Starting from the initial state $PQR = 000$:
After the first clock pulse, the counter transitions to $011$.
After the second clock pulse, the counter transitions to $101$.
After the third clock pulse, the counter transitions back to $000$.

Step 4: Conclusion.
Thus, the next three states of the counter are $011$, $101$, and $000$.