0195136047.pdf

440 DIGITAL CIRCUITS

ic, mA

vCE, V

iB = 0.12 mA

iB = 0

0.1 mA

0.08 mA

0.06 mA

0.04 mA

0.02 mA

8

7

6

5

4

012345678910111213

vBE, V

iB, mA

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

0.1

0.08

0.06

0.04

0.02

0

3

2

1

(a)

B

C

E

vBE vCE

iC

iB +

+

−−

12 4

(b)

t, ms

Vi, V

2

3

Figure P9.1.6

9.2.7For the DTL gate shown in Figure P9.2.6, as-

sume ideal diodes,VT = 0 .7V,Vsat = 0 .2V,

RB=10 k, RC= 500 , andVCC=5 V. As-

sumingβ=20 for the BJT and using reasonable

approximations, sketch the outputVofor the input

signals of Figure P9.2.7.

*9.2.8A gate using resistor-transistor logic (RTL) is

shown in Figure P9.2.8. Justify that this gate per-

forms the NOR function.

9.2.9Study the DTL gate circuit shown in Figure P9.2.9

and state whether it behaves like a NOR gate or a

NAND gate.