SEM ICON D UCTOR
S N 74LS 1 38 H (Control u n it IC5 1 )
!
G I
[
m
E n a b l e inputs
inputs
+ 5V
,u PD7800
+ 5 V
MB8418
pPD825 1
Pi n i
I
CS
TRUTH
TABLE
I n p ut
E n a b l e
G ,
G 2
c
x
H
x
L
x
x
H
L
L
H
L
L
H
L
L
H
L
L
H
L
H
H
L
H
H
L
H
H
L
H
Note :
1 . G 2 = G 2A + G 2B
2 .
H: High level
L: Low level
X: "H" or " L "
S e l ect
B
A
Yo
x
x
H
x
x
H
L
L
L
L
H
H
H
L
H
H
H
H
L
L
H
L
H
H
H
L
H
H
H
H
Output
Y,
Y 2
Y 3
v.
Y s
y6
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
L
H
H
H
H
H
H
L
H
H
H
H
H
H
L
H
H
H
H
H
H
L
H
H
H
H
H
H
L
H
H
H
H
H
H
TS-44DS
Y 1
H
H
H
H
H
H
H
H
H
L
2 7