Digital Systems: Principles and Design

4

Digital Systems

EXAMPLES

Using the circuit in Figure 1.1, fill the Table 1.3 given below: (Write logic state 1 when

V

D

> 2.8 V and less than 5 V and 0 when V < 0.8 V. Write * when indeterminate).

Example 1.1

TABLE 1.3

8

,

Logic state at ,8

,

Logic state at ,

5 V 1 1 V *

4 V 1 0.75 V 0

3.5 V 1 0.5 V 0

2 V * ~0 V 0

Consider a circuit in Figure 1.2. The circuit consists of two switches, SL and SU. One is at

the ground floor and the other at the first floor. When the lamp is ON let us assume logic

state = True and when the lamp is OFF let us assume logic state = False. Find the logic state

in different conditions of the switches and show these in Table 1.4.

TABLE ...