A. 1 B. 2 C. 3 D. 4 E. 5

9. What is the input equation for D flip-flop for the circuit below?

A. A+X

B. AÅ X

C. AÅ XÅ Y

D. XÅ Y

E. XÅ Y¤A

10. For the circuit below X=1, B=1, Y=1, C=1. What will be the next state for the flip-flop?

A. set B. reset C. complement D. No change E. none

LABORATORY WORK # 12.

COUNTERS.

Aims: investigate the operations of switch tail ring counter and ripple counter.

PREPARATION TO LAB WORK.

1. Learn the information about flip-flops, registers and counters.

2. Prepare logic diagram of 4-stage switch-tail ring counter using 4 D-flip-flops, and draw it with application of Scheme Design System. This circuit will be used in experiment 12A.

3. Construct a 4-bit asynchronous ripple counter with 4 JK-flip-flops for the experiment 12B, and draw it with application of Scheme Design System.

4. Answer the question below in written form.

4.1. What is a word-time signal?

4.2. What is a ring counter?

4.3. What is switch tail ring counter?

4.4. What is ripple counter?

4.5. What is BCD counter?

4.6. What is the difference between synchronous and asynchronous counters?