Digital Teaching Aid
 (introduction...) Preface Introduction Fundamental Logic Operations - Lesson 1 Introduction Boolean Algebra - Lesson 2 Circuit Analysis and Design - Lesson 3 First Evaluation Karnaugh Mapping - Lesson 4 Karnaugh Mapping II - Lesson 5 Coding - Lesson 6 Flip-Flops - Lesson 7 Second Evaluation Counter - Lesson 8 Data Processing Circuits - Lesson 9 Third Evaluation Answers to Evaluation Problems

### Third Evaluation

No. 1 At a distribution point of a conveyer belt a flap which is controlled by a counter circuit is to divert arriving piece-goods always six to the left and four to the right.

Fig. 1

The counting pulses T are supplied by a light barrier immediately before the diverting flap. The flap opens the way to the left if the control instructions are x = 1, y = 0 and to the right when x = 0, y = 1

Develop the truth table. Use the sum of product method. For the simplification use a Karnaugh map. Design the logic circuit.

Take a decimal counter with four output lines (20, 21, 22, 23).

No. 2 Sketch an asynchronous mod 16 counter. Use JK-MS flip flops.

No. 3 Show how to connect a 74150 multiplexer (Fig. 2) to implement the following boolean equation:

Fig. 2

No. 4 Input signals R and T are low in Fig. 3. Which is the active output line when A B C D = 0011?

No. 5 To get the y9 output line active in Fig. 3, what are the input signals you need?

Fig. 3