Elenco Electronics EP-130, Руководство пользователя

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Our last projects let you see how data could be sent
to two or more different outputs. You can probably
think of some situations where we might want (or
need) to do the opposite – send data from two or
more different sources to output. The following circuit
shows how to send data this way.
When you look at the schematic for this project,
you’ll notice two different input sources. The
multivibrator circuit provides one input signal to
control LED 2. The other signal is provided by – can
you guess?
Yourself! You provide the input signal by pressing
and relieving the key. The action of the key controls
LED 1.
Set the switch to A before you complete this project.
When you connect terminals 13 and 14 to switch on
the power LED 2 blinks. Watch both LED 1 and LED 3.
Is anything happening yet? Now press the key and
see what happens to LED 1 and LED 3. LED 3 goes
on and off at the same time as LED 1. Now set the
switch to B. LED 3 turns on and according to the
blinking of LED 2. You can use either of the two
sources as the input to determine the output of LED 3.
Now put on your thinking cap and try to follow the
inputs from the multivibrator, to the key, to the setting
of the switch, to the LED. Mark a 1 or 0 by each
terminal of the NANDs to see the different high and
low inputs.
Computers and other highly advanced digital circuits
use a more complex version of these circuits. As you
probably suspect, switching from one input channel
to another is done electronically in most cases.
Notes:
EXPERIMENT #47: TTL DATA SELECTOR
Wiring Sequence:
o
13-49-42-45-131-137
o
14-119
o
73-50-31-138
o
86-82-74-72-80-62-33-36-39-121-133
o
71-57-34-44-114
o
37-61
o
40-113-85
o
41-116-79
o
51-53-54-132
o
43-115-81
o
52-59
o
55-56
o
58-60
o
13-14 (POWER)
Schematic