Elenco Electronics EP-130, Manual

Page: 62 / 160

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It isn’t hard to think of situations where we might
want to send input data to two or more different
outputs. This project shows how we can use a
network of NAND gates to help do just that.
You can see that we use a multivibrator and three
NAND gates in this circuit. You can leave the switch
at either A or B as you build this project. When you
connect terminals 13 and 14, you’ll see that LED 1
is blinking. If the switch is at A, LED 2 is blinking
also. If the switch is at B, LED 3 blinks.
As you can see on the schematic, setting the switch
to A or B controls the inputs to the two NANDs that
light LED 2 and LED 3. With the switch at A, the
NAND controlling LED 2 gets one steady input of 1.
The output of the multivibrator supplies the other
input. As the multivibrator’s output switches from 0
to 1, the NAND controlling LED 2 switches its output
from 1 to 0.
The opposite happens when you set the switch to B.
Now the NAND controlling LED 3 gets a steady
input of 1 so that LED 3 can go on and off according
to the input from the multivibrator.
Notes:
EXPERIMENT #46: TTL LINE SELECTOR
Wiring Sequence:
o
13-49-34-37-42-45-131
o
14-119
o
71-57-54-31-44-114
o
86-82-80-72-59-60-62-33-121-133
o
36-55
o
39-58
o
40-113-85
o
41-116-79
o
43-115-81
o
50-51-53-132
o
52-56
o
13-14 (POWER)
Schematic