# Electronics and Communication Engineering - Digital Electronics

31.

In which counter does the maximum frequency depend on the modulus?

 A. Synchronous B. Ripple C. Both synchronous and ripple D. Neither synchronous nor ripple

Explanation:

Since propagation delays of all flip-flops are added in ripple counter, the maximum frequency depends on the number of flip-flops which depends on modulus.

32.

A current tracer responds to

 A. steady current only B. pulsating current only C. both pulsating and steady current D. none of the above

Explanation:

The indicator of current tracer glows when its tip is held over a pulsating current path.

33.

A presettable counter with 4 flip flops can start counting from

 A. 0000 B. 1000 C. any number from 0000 to 1000 D. any number from 0000 to 1111

Explanation:

Since 4 flip-flops are used it can count from 0000 to 1111. By presetting it can start from any number.

34.

A logical expression Y = A + AB is equal to

 A. Y = AB B. Y = AB C. Y = A + B D. Y = A + B

Explanation:

Y = A + A B = (A + A) (A + B) = (A + B).

35.

Using the same flip flops

 A. a synchronous flip flop can operate at higher frequency than ripple counter B. a ripple counter can operate at higher frequency than synchronous counter C. both ripple and synchronous counter can operate at the same frequency D. can not determine