Elenco Projects 1-101 User Manual

Copyright © 2012, 2010 by Elenco®Electronics, Inc. All rights reserved. No part of this book shall be reproduced by 753102
any means; electronic, photocopying, or otherwise without written permission from the publisher.

REV-H Revised 2012

Patent # 7144255

Project 58

-1-

1. Most circuit problems are due to incorrect
assembly, always double-check that your circuit
exactly matches the drawing for it.

2. Be sure that parts with positive/negative markings
are positioned as per the drawing.

3. Be sure that all connections are securely snapped.

4. Try replacing the batteries.

5. If the motor spins but does not balance the fan,
check the black plastic piece with three prongs on
the motor shaft. Be sure that it is at the top of the
shaft.

Elenco

®

is not responsible for parts damaged due to

incorrect wiring.

Basic T roub leshooting

Note: If you suspect you have damaged parts, you can follow

the Advanced Troubleshooting procedure on page 6 to
determine which ones need replacing.

Basic T roubleshooting 1
Parts List 2
How to Use It 3
About Your Snap Circuits

®

Parts 4

DO’s and DON’Ts of Building Circuits 5

Advanced T r oubleshooting 6
Project Listings 7
Projects 1 - 101 8 - 44
Other Snap Circuits

®

Projects 45

Snap Circuits

®

Project Shapes 46

WARNING: SHOCK HAZARD - Never connect Snap

Circuits®to the electrical outlets in your home in any wa y!

Table of Contents

WARNING: Always check your wiring

before turning on a circuit. Never leave
a circuit unattended while the batteries
are installed. Never connect additional
batteries or any other power sources
to your circuits. Discard an y cracked or
broken parts.

Adult Supervision: Because children’s

abilities var

y so much, even with age
groups, adults should exercise
discretion as to which experiments are
suitable and safe (the instructions
should enable supervising adults to

establish the experiment’s suitability
for the child). Make sure your child
reads and follows all of the relevant
instructions and safety procedures,
and keeps them at hand for reference.

This product is intended for use by
adults and children who have attained
sufficient maturity to read and follow
directions and warnings.

Never modify your parts, as doing so
may disable important safety features
in them, and could put your child at
risk of injury.

W ARNING FOR ALL PROJECTS WITH A SYMBOL - Moving parts. Do not touch the motor or f an during operation.

Do not lean over the motor. Do not launch the fan at people, animals, or objects. Eye protection is recommended.

!

!

!

WARNING: CHOKING HAZARD -

Small parts. Not for children under 3 years.

!

Conforms to

ASTM

F963-96A

• Use only 1.5V AA type, alkaline

batteries (not included).

• Insert batteries with correct polarity.

• Non-rechargeable batteries should not

be recharged. Rechargeable batteries
should only be charged under adult
supervision, and should not be
recharged while in the product.

• Do not mix old and new batteries.

• Do not connect batteries or battery
holders in parallel.

• Do not mix alkaline, standard (carbon­zinc), or rechargeable (nic kel-cadmium)
batteries.

•

Remove batteries when they are used up.

• Do not short circuit the battery
terminals.

• Never throw batteries in a fire or
attempt to open its outer casing.

• Batteries are harmful if swallowed, so
keep away from small children.

Batteries:

!

Note: If you have the more advanced Models SC-300, SC-500, or SC-750, there are additional part lists in the other project manuals.

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free [phone] or e-mail us at:

[e-mail]. Customer Service • 150 Carpenter Ave. • Wheeling, IL 60090 U.S.A.

Qty. ID Name Symbol Par t # Qty. ID Name Symbol Par t #

 1

Base Grid
(11.0” x 7.7”)

6SCBG

 1

Red Light Emitting
Diode (LED)

6SCD1

 3

1-Snap Wire 6SC01

 1

2.5V Lamp 6SCL1

 6

2-Snap Wire 6SC02

 1

Battery Holder -

uses

2 1.5V type AA (not included)

6SCB1

 3

3-Snap Wire 6SC03

 1

Speaker 6SCSP

 1

4-Snap Wire 6SC04

 1

Music
Integrated Circuit

6SCU1

 1

5-Snap Wire 6SC05

 1

Alarm
Integrated Circuit

6SCU2

 1

6-Snap Wire 6SC06

 1

Space War
Integrated Circuit

6SCU3

 1

Whistle Chip 6SCWC

 1
 1

Motor
Fan

6SCM1

6SCM1F

 1

Slide Switch 6SCS1

 1

100Ω Resistor 6SCR1

 1

Press Switch 6SCS2

 1
 1

Jumper Wire (Black)
Jumper Wire (Red)

6SCJ1
6SCJ2

 1

Photoresistor 6SCRP

You may order additional / replacement parts at our
website: www.snapcircuits.net

WC

6

5

4

3

2

1

S1

S2

RP

M1

U3

U2

U1

SP

B1

L1

D1

R1

-2-

Parts List (Colors and styles may vary) Symbols and Numbers

-3-

The Electronic Snap Circuits®kit has 101 projects. They are
simple to build and understand.

The Snap Circuits

®

kit uses building bloc ks with snaps to build
the different electrical and electronic circuits in the projects.
Each block has a function: there are switch blocks, lamp
blocks, battery bloc ks, diff erent length wire b loc ks, etc. These
blocks are in different colors and have numbers on them so
that you can easily identify them. The circuit you will build is
shown in color and with numbers, identifying the blocks that
you will use and snap together to form a circuit.

For Example:

This is the switch block which is green and has the marking
on it as shown in the drawings. Please note that the drawing
doesn’t reflect the real switch bloc k e xactly (it is missing the ON
and OFF markings), but gives you the general idea of which
part is being used in the circuit.

This is a wire block which is blue and comes in different wire
lengths.
This one has the number , , , , or on it
depending on the length of the wire connection required.

There is also a 1-snap wire that is used as a spacer or for
interconnection between different layers.

To build each circuit, you have a power source block
number that needs two (2) “AA” batteries (not included
with the Snap Circuits

®

kit).

A large clear plastic base grid is included with this kit to help
keep the circuit blocks properly spaced. You will see evenly
spaced posts that the different blocks snap into. You do not
need this base to build your circuits, but it does help in
keeping your circuit together neatly. The base has rows
labeled A-G and columns labeled 1-10.

Next to each part in every circuit drawing is a small number
in black. This tells you which level the component is placed
at. Place all parts on lev el 1 first, then all of the parts on level
2, then all of the parts on level 3, etc.

Usually when the motor is used, the fan will usually be
placed on it. On top of the motor shaft is a black plastic piece
(the motor top) with three little tabs. Lay the fan on the black
piece so the slots in its bottom “fall into place” around the
three tabs in the motor top. If not placed properly, the fan will
fall off when the motor starts to spin.

Some circuits use the jumper wires to make unusual
connections. Just clip them to the metal snaps or as
indicated.

Note: While building the projects, be careful not to
accidentally make a direct connection across the battery
holder (a “short circuit”), as this may damage and/or quickly
drain the batteries.

How To Use It

S1

2 3 4 5 6

M1

B1

(Part designs are subject to change without notice).

Note: If you have the more advanced Models SC-300, SC-500, or SC-750,
there is additional inf

ormation in your other project manual(s).

The base grid functions like the printed circuit boards found in most
electronic products.

It is a platform for mounting parts and wires (though the

wires are usually “printed” on the board.
The blue snap wires are just wires used to connect other components, they

are used to transpor

t electricity and do not affect circuit performance. They
come in different lengths to allow orderly arrangement of connections on the
base grid.

The red and black jumper wires make flexible connections for times when
using the snap wires would be difficult.

They also are used to make

connections off the base grid (like the projects using water).
The batteries (B1) produce an electrical voltage using a chemical reaction.

This “v

oltage” can be thought of as electrical pressure, pushing electrical
“current” through a circuit. This voltage is much lower and much safer than
that used in your house wiring. Using more batteries increases the “pressure”
and so more electricity flows.

The slide switch (S1) connects (ON) or disconnects (OFF) the wires in a
circuit.

When ON it has no effect on circuit performance.

The press switch (S2) connects (pressed) or disconnects (not pressed) the
wires in a circuit, just like the slide s

witch does.

Resistors, such as the 100Ω resistor (R1), “resist” the flow of electricity and
are used to control or limit the electricity in a circuit.

Increasing circuit

resistance reduces the flow of electricity.
The photoresistor (RP) is a light-sensitive resistor, its value changes from

nearly infinite in total darkness to about 1000Ω when a bright light shines on it.
A light bulb, such as in the 2.5V lamp (L1), contains a special wire that glows

bright when a large electric current passes through it. Voltages above the
bulb’s rating can burn out the wire.

The motor (M1) converts elecricity into mechanical motion. Electricity is
closely related to magnetism, and an electric current flo

wing in a wire has a
magnetic field similar to that of a very, very tiny magnet. Inside the motor is
three coils of wire with many loops. If a large electric current flows through
the loops, the magnetic effects become concentrated enough to move the
coils. The motor has a magnet inside so, as the electricity moves the coils to
align them with the permanent magnet, the shaft spins.

The speaker (SP) converts electricity into sound. It does this by using the
energy of a changing electrical signal to create mechanical vibr

ations (using

a coil and magnet similar to that in the motor), these vibrations create
variations in air pressure which travel across the room. You “hear” sound
when your ears feel these air pressure variations.

The whistle chip (WC) contains two thin plates. When an electrical signal is
applied across them the

y will stretch slightly in an eff

ort to separate (like two
magnets opposing each other), when the signal is removed they come back
together. If the electrical signal applied across them is changing quickly, then
the plates will vibrate. These vibrations create variations in air pressure that
your ears feel just like sound from a speaker.

The LED (D1) is a light emitting diode, and may be thought of as a special
one-wa

y light bulb. In the “forward” direction (indicated by the “arrow” in the

symbol) electricity flows if the voltage exceeds a turn-on threshold (about

1.5V); brightness then increases. A high current will burn out the LED, so the
current must be limited by other components in the circuit. LEDs block
electricity in the “reverse” direction.

Some types of electronic components can be super-miniaturized, allowing
many thousands of parts to fit into an area smaller that your fingernail. These
“integrated circuits” (ICs) are used in everything from simple electronic toys to
the most advanced computers. The music, alarm, and space war ICs (U1,
U2, and U3) in Snap Circuits

®

are actually modules containing specialized
sound-generation ICs and other supporting components (resistors,
capacitors, and transistors) that are always needed with them. This was done
to simplify the connections you need to make to use them. The descriptions
for these modules are given here for those interested, see the projects for
connection examples:

(+)

HLD

OUT

(–)

TRG

IN1

(–)

IN2

IN3

OUT

IN1

(+)

OUT

IN2

(–)

Music IC:

(+) - power from batteries
(–) - power return to batteries
OUT - output connection
HLD - hold control input
TRG - trigger control input

Music for a few seconds on power-up, then hold HLD to (+)
power or touch TRG to (+) power to resume music.

Alarm IC:

IN1, IN2, IN3 - control inputs
(–) - power return to batteries
OUT - output connection

Connect control inputs to (+) power to make five alarm
sounds, see project 22 for configurations.

Space War IC:

(+) - power from batteries
(–) - power return to batteries
OUT - output connection
IN1, IN2 - control inputs

Connect each control input to (–) power to sequence through
8 sounds.

-4-

About Your Snap Circuits®Parts

Our Student Guides give much more information about your parts along with a complete lesson
in basic electronics. See www.snapcircuits.net/learn.htm or page 45 for more information.

-5-

DO’s and DON’Ts of Building Circuits

After building the circuits given in this booklet, you ma y wish to e xperiment
on your own. Use the projects in this booklet as a guide, as many
important design concepts are introduced throughout them. Every circuit
will include a power source (the batteries), a resistance (which might be
a resistor, lamp, motor, integrated circuit, etc.), and wiring paths between
them and back. You must be careful not to create “shor t circuits” (very

low-resistance paths across the batter

ies, see examples below) as this

will damage components

and/or quickly drain your batteries. Only

connect the ICs using configurations given in the projects, incorrectly
doing so may damage them. Elenco®is not responsible for parts

damaged due to incorrect wiring.

Here are some important guidelines:

ALWAYS

USE EYE PROTECTION WHEN EXPERIMENTING ON YOUR O WN.

ALWAYS

include at least one component that will limit the current
through a circuit, such as the speaker, lamp, whistle chip, ICs
(which must be connected properly), motor, photoresistor, or
resistor.

ALWAYS

use the LED and switches in conjunction with other
components that will limit the current through them. Failure to
do so will create a short circuit and/or damage those par ts.

ALWAYS

disconnect your batteries immediately and check your wiring if
something appears to be getting hot.

ALWAYS

check your wiring before turning on a circuit.

ALWAYS

connect ICs using configurations given in the projects or as per
the connection descriptions for the parts.

NEVER

connect to an electrical outlet in your home in any way.

NEVER

leave a circuit unattended when it is turned on.

NEVER

touch the motor when it is spinning at high speed.

Note: If you have the more advanced Models SC-300, SC-500, or SC-750,
there are additional guidelines in your other project manual(s).

For all of the projects given in this book, the parts may be arranged in
different ways without changing the circuit. For example, the order of
parts connected in series or in parallel does not matter — what matters is
how combinations of these sub-circuits are arranged together.

Examples of SHORT CIRCUITS - NEVER DO THESE!!!

You are encouraged to tell us about new circuits you create. If they are
unique, we will post them with your name and state on our website at
www.snapcircuits.net/kidkreations.htm. Send your suggestions to
Elenco

®

.

Elenco®provides a circuit designer so that you can make your own Snap
Circuits®drawings. This Microsoft®Word document can be downloaded
from www.snapcircuits.net/SnapDesigner.doc or through the

www.snapcircuits.net website.

WARNING: SHOCK HAZARD - Nev

er connect Snap Circuits®to

the electrical outlets in your home in any way!

Placing a 3-snap wire directly
across the batteries is a
SHORT CIRCUIT.

This is also a

SHORT CIRCUIT.

When the slide switch (S1) is turned on, this large circuit has a SHORT
CIRCUIT path (as shown by the arrows). The short circuit prevents any
other portions of the circuit from ever working.

!

!

!

NEVER

DO!

NEVER

DO!

NEVER

DO!

NEVER

DO!

Warning to Snap Rover owners: Do not connect your parts to the

Rover body except when using our approved circuits, the Rover
body has a higher voltage which could damage your parts.

!

!

NEVER

DO!

!

-6-

Advanced Troubleshooting (Adult supervision recommended)

Elenco

®

is not responsible for parts damaged due to incorrect

wiring.

If you suspect you have damaged parts, you can follow
this procedure to systematically determine which ones
need replacing:

1.2.5V lamp (L1), motor (M1), speaker (SP), and battery holder

(B1): Place batteries in holder. Place the 2.5V lamp directly

across the battery holder

, it should light. Do the same with the
motor (motor + to battery +), it should spin to the right at high
speed. “Tap” the speaker across the battery holder contacts, you
should hear static as it touches. If none work, then replace your
batteries and repeat, if still bad then the battery holder is
damaged.

2.Jumper wires: Use this mini­circuit to test each jumper wire,
the lamp should light.

3.Snap wires: Use this mini­circuit to test each of the snap
wires, one at a time

. The lamp

should light.

4.Slide switch (S1) and Press switch (S2): Build project #1, if
the lamp (L1) doesn’t light then the slide switch is bad.

Replace

the slide switch with the press switch to test it.

5.100Ω resistor (R1) and LED (D1): Build project #7 except
initially use the speaker (SP) in place of the resistor

, the LED
should light. Then replace the speaker with the resistor; the LED
should still light.

6.Alarm IC (U2): Build project #17, you should hear a siren. Then
place a 3-snap wire between g

rid locations A1 and C1, the
sound is different. Then move the 3-snap from A1-C1 to A3-C3
to hear a 3rd sound.

7.Music IC (U1): Build project #74 but use the press switch (S2)
in place of the photoresistor (RP).

Turn it on and the LED (D1)
flickers for a while and stops, it resumes if you press and hold
down the press switch. Then touch a 3-snap wire across base
grid points A1 and C1 and the flickering resumes for a while.

8.Space war IC (U3) and photoresistor (RP): Build project #19,
both switches (S1 and S2) should change the sound.

Then
replace the slide switch with the photoresistor, waving your hand
over it should change the sound.

9.Whistle chip (WC): Build project #61 and if there is light on the
photoresistor (RP) then you will hear sound from the whistle
chip

.

Note: If you have the more advanced models SC-300, SC-500, or
SC-750, there are additional tests in your other project manual(s).

ELENCO

®

150 Carpenter Avenue

Wheeling, IL 60090 U.S.A.

Phone: [phone]

Fax: [phone]

e-mail: [e-mail]

Website: www.elenco.com

You may order additional / replacement parts at:

www.snapcir

cuits.net

-7-

Project # Description Page #

1 Electric Light & Switch 8
2 DC Motor & Switch 8
3 Sound Activated Switch 9
4 Adjusting Sound Level 9
5 Lamp & Fan in Series 10
6 Lamp & Fan in Parallel 10
7 Light Emitting Diode 11
8 One Direction for LED 11

9 Conduction Detector 12
10 Space War Alarm Combo 12
11 Flying Saucer 13
12 Decreasing Saucer Lift 13
13 Two-Speed Fan 14
14 The Fuse 14
15 Musical Doorbell 15
16 Momentary Alarm 15
17 Alarm Circuit 16
18 Laser Gun 16
19 Space War 17
20 Light Switch 17
21 Paper Space War 17
22 Light Police Siren 18
23 More Loud Sounds 18
24 More Loud Sounds (II) 18
25 More Loud Sounds (III) 18
26 More Loud Sounds (IV) 18
27 Clap Sounds 19
28 More Clap Sounds 19
29 More Clap Sounds (II) 19
30 More Clap Sounds (III) 19
31 More Clap Sounds (IV) 19
32 Voice Light Diode 20
33 Voice Control 20
34 Motor Space Sounds 20

Project # Description Page #

35 Motor Space Light 20
36 Space Battle (II) 21
37 Silent Space Battle 21
38 Periodic Sounds 21
39 Blinking Double Flashlight 21
40 Motor-Controlled Sounds 22
41 More Motor Sounds 22
42 More Motor Sounds (II) 22
43 More Motor Sounds (III) 22
44 More Motor Sounds (IV) 22
45 Light-Controlled Flicker 23
46 More Sound Effects 23
47 This OR That 24
48 This AND That 24
49 Neither This NOR That 25
50 NOT This AND That 25
51 Reflection Detector 26
52 Quieter Reflection Detector 26
53 Flashing Laser Light with Sound 27
54 Space War Flicker 27
55 Spinning Rings 28
56 Strobe the House Lights 28
57 Race Game 29
58 Using Parts as Conductors 29
59 Spin Draw 30
60 Space War Flicker Motor 30
61 Light-Controlled Sounds 31
62 Light-Controlled Sounds (II) 31
63 Light-Controlled Sounds (III) 31
64 Light-Controlled Sounds (IV) 31
65 Light-Controlled Sounds (V) 31
66 Electronic Bombing Game 32
67 Quiet Zone Game 33
68 Space War Music Combo 33

Project # Description Page #

69 Space War Siren 34
70 Quiet Water Alarm 34
71 Light-Controlled Lamp 35
72 Voice-Controlled Lamp 35
73 Motor-Controlled Lamp 35
74 Light-Controlled LED 36
75

Sound-Controlled Time Delay LED

36

76

Motor-Controlled Time Delay LED

36
77 Space War Flicker LED 37
78 Music AND Gate 37
79 Flash and Tone 37
80

Lamp, Speaker & Fan in Parallel

38
81 Pencil Alarm 38
82 Pencil Alarm Variants 38
83 Fun with the Alarm IC 39
84 Motor Sounds Combo 39
85 Motor Sounds Combo (II) 39
86 Music Alarm Combo 40
87 Bomb Sound 40
88 Bomb Sound (II) 40
89 Light-Controlled LED (II) 41
90 Touch Light 41
91 Touch Sound 41
92 Wacky Sounds 41
93 Wackier Sounds 42
94 Really Wacky Sounds 42
95 Noisier Water Space War 43
96 Light/Water Space War 43
97 OR/AND Space War Light 43
98 Simple Water Alarm 44
99 Simple Salt Water Alarm 44

100 Ambulance Water Alarm 44
101 Ambulance Contact Alarm 44

Project Listings

-8-

Project #1

OBJECTIVE: To show ho w electricity is turned “ON” or “OFF”
with a switch.

Electric Light & Switch

Project #2

OBJECTIVE: To show how electricity is used to run a Direct
Current (DC) Motor.

Build the circuit shown on the left by placing all the parts with a black 1 next
to them on the base grid first. Then, assemble parts marked with a 2.

When you close the slide switch (S1), current flows from the batteries
(B1) through the motor (M1) making it rotate. Place the fan blade on
the motor shaft and close the slide switch. The motor will rotate f orcing
the fan blade to move air past the motor.

In this project, you changed electrical power into mechanical power.
DC motors are used in all the battery powered equipment requiring
rotary motion, such as a cordless drill, electric toothbrush, and toy
trains that run on batteries just to name a few. An electric motor is
much easier to control than gas or diesel engines.

DC Motor & Switch

Build the circuit shown on the left by placing all the parts with a black 1 next
to them on the base grid first. Then, assemble parts marked with a 2.
Install two (2) “AA” batteries (not included) into the batter y holder (B1).

When you close the slide switch (S1), current flows from the batteries
through the lamp and back to the battery through the switch. The closed
switch completes the circuit. In electronics this is called a closed circuit.
When the slide switch is opened, the current can no longer flow back to
the battery, so the lamp goes out. In electronics this is called an open
circuit.

!

WARNING: Moving parts. Do not touch the fan or

motor during operation. Do not lean o ver the motor.

+

-9-

Project #3

OBJECTIVE: To show how sound can turn “ON” an electronic
device.

Build the circuit shown on the left by placing all the parts with a black 1
next to them on the base grid first. Then, assemble parts marked with
a 2. Finally, lay the speaker (SP) on the table and connect it to the
circuit using the jumper wires as shown.

When you close the slide switch (S1), the music may play for a short
time, and then stop. After the music has stopped, clap your hands
close to the whistle chip (WC) or tap the base with your finger. The
music should play again f or a short time, then stop. Blow on the whistle
chip and the music should play.

You could connect the speaker using snap wires instead of the jumper
wires, but then the speaker may create enough sound vibrations to re­activate the whistle chip.

Sound Activated Switch

Project #4

OBJECTIVE: To show how resistance can lower the sound from
the speaker.

Build the circuit shown on the left.

When you close the slide switch
(S1), the music may play for a short time and then stop. After the
music has stopped, clap your hands close to the whistle chip (WC) or
tap the base with your finger. The music should play again for a short
time, then stop.

In this project, you changed the amount of current that goes through
the speaker (SP) and reduced the sound output of the speaker.
Resistors are used throughout electronics to limit the amount of
current that flows.

Adjusting Sound Level

Visit www.snapcircuits.net or page 45 to learn about Snap Circuits®upgrade kits, which have more parts and circuits.

-10-

Project #5

OBJECTIVE: To show how a lamp can indicate when a fan is
running.

Build the circuit shown on the left by placing all the parts with a black 1
next to them on the base grid first. Then, assemble parts marked with
a 2. Finally, place the fan blade on the motor (M1).

When you close the slide switch (S1), the fan will spin and the lamp
(L1) should turn on. The fan will take a while to start turning due to
inertia. Inertia is the property that tr ies to keep a body at rest from
moving and tries to keep a moving object from stopping.

The light helps protect the motor from getting the full voltage when the
slide switch is closed. Part of the voltage goes across the lamp and the
rest goes across the motor. Remove the fan and notice how the lamp
gets dimmer when the motor does not have to spin the fan blade.

Lamp & Fan in Series

Project #6

OBJECTIVE: To show how an indicator light can be connected
without affecting the current in the motor.

Build the circuit shown on the left.
When you close the slide switch (S1), both the fan and the lamp (L1)

should turn on. The fan will take a while to start turning due to inertia.
In this connection, the lamp does not change the current to the motor
(M1). The motor should start a little faster than in Project #5.

Remove the fan and notice how the lamp does not change in
brightness as the motor picks up speed. It has its own path to the
battery (B1).

Lamp & Fan in Parallel

!

WARNING: Moving parts. Do not touch the fan or

motor during operation. Do not lean o ver the motor.

!

WARNING: Moving parts. Do not touch the fan or

motor during operation. Do not lean o ver the motor.

-11-

Project #7

OBJECTIVE: To show ho w a resistor and LED are wired to emit
light.

Build the circuit shown on the left by placing all the parts with a black 1 next
to them on the base grid first. Then, assemble parts marked with a 2.

When you close the slide switch (S1), current flows from the batteries
(B1) through the slide switch, through the resistor (R1), through the
LED (light emitting diode, D1) and back to the battery. The closed slide
switch completes the circuit. The resistor limits the current and
prevents damage to the LED. NEVER PLACE AN LED DIRECTLY
ACROSS THE BATTERY! If no resistor is in the circuit, the battery may
push enough current through the LED to damage the semiconductor
that is used to produce the light. LEDs are used in all types of
electronic equipment to indicate conditions and pass information to the
user of that equipment.

Can you think of something you use everyday that has an LED in it?

Light Emitting Diode

Project #8

OBJECTIVE: To show how electricity can only pass in one
direction through an LED.

Rebuild the circuit used in Project #7 but put the LED (D1) in as shown
on the left.

When you close the slide switch (S1), current should flow from the
batteries (B1) through the resistor and then through the LED. When
current flows through an LED, it lights up. Since the LED is in
backwards, current cannot flow. The LED is like a check valve that lets
current flow in only one direction.

In this project, you changed the direction of current through the LED. An
electronic component that needs to be connected in one direction is
said to have polarity. Other parts like this will be discussed in future
projects. Placing the LED in backwards does not harm it because the
voltage is not large enough to break down this electronic component.

One Direction for LED

+

-12-

Project #9

OBJECTIVE: To make a circuit that detects the conduction of
electricity in different materials.

Rebuild the circuit from Project #7 but leave the slide switch (S1) out
as shown on the left.

When you place a metal paper clip across the terminals as shown in
the picture on the left, current flows from the batteries (B1) through the
resistor (R1), through the LED (D1), and back to the battery. The
paper clip completes the circuit and current flows through the LED.
Place your fingers across the terminals and the LED does not light.
Your body has too high of a resistance to allow enough current to flow
to light the LED . If the v oltage, which is electrical pressure, w as higher ,
current could be pushed through your fingers and the LED would light.
This detector can be used to see if a material like plastic is a good
conductor or a poor conductor.

Conduction Detector

Project #10

OBJECTIVE: To combine the sounds from the space war and

alarm integrated circuits.

Build the circuit shown and add the jumpers to complete it. Turn it on,
press the press switch (S2) several times, and wave your hand over
the photoresistor (RP) to hear all the sound combinations. If the sound
is too loud you may replace the speaker (SP) with the whistle chip
(WC).

Space War Alarm Combo

To learn more about how circuits work, visit www.snapcircuits.net or page 45 to find out about our Student Guides.

-13-

Project #11

OBJECTIVE: To make a circuit that launches the fan blade to
simulate a flying saucer.

Rebuild the circuit from Project #2, but reverse the polarity on the motor
(M1) so the negative (–) on the motor goes to the positive (+) on the
battery (B1). New alkaline batteries are recommended for this project.

When you close the slide switch (S1), the motor will slowly increase in
speed. When the motor has reached maximum rotation, turn the slide
switch off. The fan blade should rise and float through the air like a flying
saucer. Be careful not to look directly down on fan b lade when it is spinning.

The air is being blown down through the blade and the motor rotation
locks the fan on the shaft. When the motor is turned off, the blade
unlocks from the shaft and is free to act as a propeller and fly through
the air. If speed of rotation is too slow, the fan will remain on motor
shaft because it does not have enough lift to propel it. The motor will
spin faster when both batteries are new.

If the fan doesn’t fly off, then turn the switch on and off several times
rapidly when it is at full speed.

Flying Saucer

Project #12

OBJECTIVE: To show how voltage affects speed of a DC motor
and can decrease the lift of the saucer.

Change the circuit in Project #11 by adding the lamp (L1) in series with
the motor as shown in the diagram on the left.

When you place the lamp in series with any electronic device, it will
draw less current because it adds resistance. In this case, the lamp in
series reduces the current through the motor, and that reduces the top
speed of the motor. Close the slide switch (S1), and wait until the fan
reaches maximum speed. Open the s witch and observe the difference
in the height due to the lamp. In most cases, it may not even launch.

Decreasing Saucer Lift

+

!

WARNING: Moving parts. Do not touch the fan or

motor during operation. Do not lean over the motor.

!

WARNING: Fan may not

rise until switch is released.

!

WARNING: Moving parts. Do not touch the fan or

motor during operation. Do not lean over the motor.

!

WARNING: Fan may not

rise until switch is released.

-14-

Project #13

OBJECTIVE: To show how switches can increase or decrease
the speed of an electric fan.

Build the circuit shown on the left by placing all the parts with a black
1 next to them on the board first. Then, assemble parts marked with
a 2. Finally, add the 2-snap wires that are marked for level three.

When you close the slide switch (S1), current flows from the batteries
through the slide switch (S1), motor (M1), the lamp (L1), and back to
the battery (B1). When the press switch (S2) is closed, the lamp is
shorted and motor speed increases.

The principle of removing resistance to increase motor speeds is only
one way of changing the speed of the motor. Commercial fans do not
use this method because it would produce heat in the resistor and fans
are used to cool circuits by moving air over them. Commercial fans
change the amount of voltage that is applied to the motor using a
transformer or other electronic device.

Two-Speed Fan

OBJECTIVE: To show how a fuse is used to break all current
paths back to the voltage source.

Use the circuit built in Project #13.
When you close the slide switch (S1), current flows from the batteries

through the slide switch (S1), the lamp (L1), motor (M1), and back to the
battery (B1). Pretend the 2-snap wire marked fuse in the drawing on the
left is a device that will open the circuit if too much current is taken from
the battery. When press switch (S2) is closed, the light is shorted and
motor speed increases due to an increase in current to the motor. While
still holding press switch (S2) down, remove the 2-snap wire marked
fuse and notice how everything stops. Until the fuse is replaced, the
open circuit path protects the electronic parts. If fuses did not exist,
many parts could get hot and even start fires. Replace the 2-snap wire
and the circuit should return to normal.

Many electronic products in your home hav e a fuse that will open when
too much current is drawn. Can you name some?

The FuseProject #14

!

WARNING: Moving

parts. Do not touch the
fan or motor during
operation. Do not lean
over the motor.

!

WARNING: Moving

parts. Do not touch the
fan or motor during
operation. Do not lean
over the motor.