UGC NET CSE | December 2004 | Part 2 | Question: 10

Question

The characteristic equation of a $\text{T}$ flip-flop is :

• A. $Q_{n+1}=T\overline Q_n+\overline T Q_n$
• B. $Q_{n+1}=T+Q_n$
• C. $Q_{n+1}=TQ_n$
• D. $Q_{n+1}=\overline T$$\overline Q_n$

The symbols used have the usual meaning.

Answer 1

Option A

Present state EX-OR with T gives next state

Answer 2

in T flip flop if the input value is low (0) it remains in the previous state but if the input value is high(1) it basically changes the state (Toggle/complement) 

characteristic table of T flip flop:

$T$	$Q_n$	$Q_{n+1}$
$0$	$0$	$0$
$0$	$1$	$1$
$1$	$0$	$1$
$1$	$1$	$0$

From the above table $Q_{n+1}=\bar TQ_n+T\bar Q_n$

or $Q_{n+1}=T\oplus Q_n$

Option $(A)$ is correct here.