Elenco Electronics EP-130 - Op Amp Three-Input AND Gate

-
126
-
Who says an operational amplifier
(
op amp
)
can’t b
e
used to make a di
g
ital circuit? Here, you will use on
e
to make an AND
g
ate. The LED display is the outpu
t
device. If it displays nothin
g
, at least one of the outpu
t
signals is logical 0 or low; if it displays H, they are al
l
logical 1 or high
.
When you finish the wiring, turn on the power b
y
settin
g
the switch to position A. The LED remain
s
d
ar
k
.
Th
e
i
nput term
i
na
l
s are 125, 127, an
d
129
.
These terminals are connected to the ne
g
ative
(
–
)
terminal, so they do not cause the LED to li
g
ht
.
Terminal 14 is connected to the
p
ositive
(
+
)
terminal
,
so it is the lo
g
ic 1 terminal. When you connec
t
term
i
na
l
s 125, 127, an
d
129 to term
i
na
l
14
i
n var
i
ou
s
c
om
bi
nat
i
ons, you see t
h
at t
h
e
LED
li
g
h
ts an
d
s
h
ow
s
H only when terminals 125, 127, and 129 are al
l
c
onnected to terminal 14 - lo
g
ic 1
.
N
o
t
es:
EXPERIMENT #1
06
:
O
P AMP THREE-INP
U
T “AND”
G
AT
E
Wiring
S
equence:

14
-
8
5-
81
-
63
-
19
-
18
-
21
-
22
-
23
-
132

25
-47

46
-
88

7
8
-7
6
-
83
-
80
-7
0
-
48
-
121

6
7-
8
7

68
-
8
2-
8
4

86
-
69
-
126
-
128
-
130

1
29-75-
WIRE

1
27-77-WIRE

1
25-79-
WIRE

119
-
124

122
-
131
Schemati
c