MadeEasy Test Series: Digital Logic - Digital Counter

Question

In figure, initially Q = A = B = 0. After three clock triggers, the states of Q, A and B will be respectively is ___________.

Answer 1

Positive edge trigger Counter is used. 

After 3 clock pulse, new Q, A and B will be $1$,$1$ and $0$ , respectively 

Clock pulse $1$	Old Q =$0$	New Q = $1$	Q goes 0 to 1 ,  work as positive edge trigger to Counter clock, Counter goes UP	old AB = $00$	New AB = $01$
Clock Pulse $2$	Old Q =$1$	New Q =$0$	Q goes $1$ to $0$ ,  work as negative edge trigger to Counter clock, No change at Counter	old AB = $01$	New AB = $01$
Clock Pulse $3$	Old Q =$0$	New Q = $1$	Q goes 0 to 1 ,  work as positive edge trigger to Counter clock, Counter goes UP	old AB = $01$	New AB = $10$

Comments

How can we assume it is positive edge triggered??

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No I didn't assume. it is given as positive edge triggered