Elenco 130-in-1 Electronics Playground - Manual (Page 52)

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By using your kit’s NAND gates, are you able to
figure out how to make an AND gate? To find out let’s
experiment!
As you build this circuit, leave the switch at B.
connect terminals 13 and 14 to turn the power on
once you have finished. Now press the key. What
happens to LED 1? Now while pressing the key, set
the switch to A. Are there any changes in LED 1?
As you can observe by setting the switch to A and
then pressing the key, makes the inputs 1, causing
the overall output to be 1. Are you able to flow the 1
input through the circuit until you reach a 1 output?
Give it a try, but don’t peek at the answer.
Here is how it works – each 1 input goes into the first
NAND gate. Thus causing the output of the NAND to
be 0. This 0 output is used for both inputs to the
second NAND. The LED lights when the 0 inputs to
the second NAND cause its output to be 1. AND gate
is formed from two NAND gates.
Notes:
EXPERIMENT #36: “AND” GATE USING TTL
Wiring Sequence:
o 13-49-131-137
o 14-119
o 31-55
o 72-56-57-59-60-62-33-133-121
o 50-71-138
o 51-132
o 52-53-54
o 13-14 (POWER)
Schematic
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This siren gives off alternating high and low sounds.
Slide the switch to position B and construct the
circuit. After you complete the wiring and slide the
switch to position A, the power turns on and the
speaker creates the sound of a two-pitch siren.
This siren is made up of two astable multivibrators.
IC 2 provides the normal beep sound. IC 1 produces
the signal that alters the pitch of its sound at regular
intervals.
Let’s execute a small experiment now. The siren
gives out an intermittent beep instead of the two-
pitch sound once you detach the 22k
Ω resistor. Can
you decipher why? The IC 1 interrupts the siren
sound produced by IC 2.
Notes:
EXPERIMENT #90: CRISIS SIREN
Wiring Sequence:
o 1-29
o 2-30
o 3-116
o 5-83-70-108-112-121
o 85-63-131
o 64-90-92-115
o 65-107-89
o 66-82-84-86-91
o 81-94-88-67
o 93-68-111
o 69-80-87
o 79-119-124
o 122-132
Schematic