Elenco 130-in-1 Electronics Playground - Manual (Page 62)

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It isn’t hard to think of some situations where we
might want to send input data to two or more different
outputs. This experiment shows how we can use a
network of NAND gates to help do that.
This circuit uses three NAND gates and a
multivibrator. Build the circuit, connecting terminals
13 and 14 last. If the switch is set to A then LEDs 1
and 2 will be blinking; if the switch is set to B then
LEDs 1 and 3 will be blinking.
Setting the switch to A or B controls the inputs to the
two NANDs that light LED 2 and LED 3 as shown in
the schematic. When the switch is A then the NAND
is controlling LED 2 gets one steady input of 1. The
other input is supplied by the output of the
multivibrator. As the multivaibrator’s output switches
from 0 to 1, NAND controlling the LED 2 switches it
output from 1 to 0.
When you have the switch set to B, the opposite
happens. According to the input from the multivibrator
LED 3 can go on and off because the NAND
controlling the LED 3 gets a steady input of 1.
Notes:
EXPERIMENT #46: LINE SELECTOR USING TTL
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
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The LED circuits in experiments 78 and 79
(“Operational Amplifier Blinking LED” and “LED
Flasher”) each use one LED, but the circuit in this
project uses two LEDs that take turns lighting. Slide
the switch to position B and assemble the circuit.
Then, turn the power on by sliding the switch to
position A and wait for a few seconds. The LEDs light
and turn off in rotation.
The operational amplifier works as an astable
multivibrator. When the output is low, LED 2 lights;
when it is high, LED 1 lights.
You can alter the speed of the blinking by using
different values for R and C. See how the speed of
the pulses alters when you alter the value of R to
220k
Ω.
Notes:
EXPERIMENT #80: DOUBLE LED BLINKER
Schematic
Wiring Sequence:
o 31-36-67-90-94
o 33-70-135
o 34-63-132
o 93-68-113
o 81-89-69
o 82-114-124-119
o 121-134
o 122-131