SB-125 Snap Circuits Skillbuilder

INSTRUCTION MANUAL

PROJECTS
1-57
MANUAL
58-125
ONLINE

AGES 8+

Go to https://shop.elenco.com/ consumers/skillbuilder.html to download projects 58-125

Copyright © 2021 by Elenco® Electronics, Inc. All rights reserved. No part of this book shall be reproduced by any means; electronic, photocopying, or otherwise without written permission from the publisher. U.S. Patents: 7,144,255; 7,273,377, & patents pending

SOURCE CODE: SB-125V1 753124 REV-A

Table of Contents

Basic Troubleshooting

1

Parts List

2

How to Use Snap Circuits® Skill Builder 125 3

About Your Snap Circuits® Skill Builder 125 Parts 4, 5

Introduction to Electricity

6

DOs and DON’Ts of Building Circuits Advanced Troubleshooting
Projects 1 – 57

7 8 1-30

WARNING: SHOCK HAZARD – Never connect Snap Circuits® Skill Builder 125 to the electrical outlets in your home in any way!

WARNING: CHOKING HAZARD –

Conforms to all applicable

! Small parts. Not for children under 3 years.

U.S. government requirements.

WARNING FOR ALL PROJECTS WITH A !

SYMBOL

!

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

not launch the fan at people, animals, or objects.

Eye protection is recommended.

Basic Troubleshooting

1. Most circuit problems are due to incorrect assembly, always double-check that your circuit exactly matches the drawing for it.
2. Be sure the motor (M1) “+” marking is positioned as per the drawing.
3. Be sure that all connections are securely snapped. 4. Try replacing the batteries.
ELENCO® is not responsible for parts damaged due to incorrect wiring.
Note: If you suspect you have damaged parts, you can follow the Advanced Troubleshooting procedure on page 8 to determine which ones need replacing.

Go to https://shop.elenco.com/ consumers/skillbuilder.html to download projects 58-125
1

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 any cracked or broken parts.
Adult Supervision: Because children’s abilities vary 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
! Batteries:
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.

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.
Do not mix alkaline, standard (carbonzinc), or rechargeable (nickel-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.

Parts List (Colors and styles may vary) Symbols and Numbers
Important: If any parts are missing or damaged in shipping, DO NOT RETURN TO Target. Call toll-free 800-533-2441 or e-mail to help@ elenco.com. Customer Service 150 Carpenter Ave. Wheeling, IL 60090 U.S.A.

Qty. ID Name

r 1

Base Grid (11.0″ x 7.7″)

r 3

1 1-Snap Wire

Symbol

Part #

Qty. ID Name

6SCBG

r 1 r 1

M1

Motor Glow Fan

6SC01 r 1

Q2 NPN Transistor

Symbol

Part #
6SCM1 6SCM1FG
6SCQ2

r 6

2 2-Snap Wire

6SC02 r 1

R1 100W Resistor

6SCR1

r 3

3 3-Snap Wire

6SC03 r 1

R2 1KW Resistor

6SCR2

r 1

4 4-Snap Wire

6SC04 r 1

RP Photoresistor

6SCRP

r 1

5 5-Snap Wire

6SC05 r 1

S1 Slide Switch

6SCS1

r 1

6 6-Snap Wire

r 1

B1

Battery Holder – uses Two 1.5V type AA (not incl.)

r 1

C5 470mF Capacitor

r 1

Red Light Emitting D1 Diode (LED)

r 1 L1 2.5V Lamp

6SC06 r 1

S2 Press Switch

6SCB1 r 1 6SCC5 r 1 6SCD1 r 1 6SCL1 r 1

SP Speaker

U1

Music Integrated Circuit

U2

Alarm Integrated Circuit

Space War U3 Integrated Circuit

6SCS2 6SCSP 6SCU1 6SCU2 6SCU3
2

How To Use It

The Snap Circuits® Skill Builder 125 uses building blocks with snaps to build the different electronic circuits in the projects. Each block has a function: there are switch blocks, light blocks, battery blocks, different length wire blocks, etc. These blocks are different colors and have numbers on them so that you can easily identify them. The blocks you will be using are shown as color symbols with level numbers next to them, allowing you to easily snap them together to form a circuit.
For Example:
This is the switch block which is green and has the marking S1 on it. The part symbols in this booklet may not exactly match the appearance of the actual parts, but will clearly identify them.

There is also a 1-snap wire that is used as a spacer or for interconnection between different layers.
1 You need a power source to build each circuit. This is labeled B1 and requires two (2) 1.5V “AA” batteries (not included).
When installing a battery, be sure the spring is compressed straight back, and not bent up, down, or to one side. Battery installation should be supervised by an adult.

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 level 1 first, then all of the parts on level 2, then all of the parts on level 3, etc.
Usually when the motor M1 is used, the glow fan will 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.

PRESSS2 SWITCH

This is a wire block which is blue and comes in different wire lengths. This one has the number 2 , 3 , 4 , 5 , or 6 on it depending on the length of the wire connection required.
2

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. The base has rows labeled

3

Note: While building circuits, 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.

About Your Snap Circuits® Skill Builder 125 Parts

(Parts are subject to change without notice).
BASE GRID
The base grid is a platform for mounting parts and wires. It functions like the printed circuit boards used in most electronic products, or like how the walls are used for mounting the electrical wiring in your home.

BATTERY HOLDER
The batteries (B1) produce an electrical voltage using a chemical reaction. This “voltage” can be thought of as electrical pressure, pushing electricity through a circuit just like a pump pushes water through pipes. This voltage is much lower and much safer than that used in your house wiring. Using more batteries increases the “pressure”, therefore, more electricity flows.

RESISTORS
Resistors “resist” the flow of electricity and are used to control or limit the current in a circuit. The Snap Circuits® Skill Builder 125 includes 100W (R1) and 1KW (R2) resistors (“K” symbolizes 1,000, so R2 is really 1,000W). Materials like metal have very low resistance (<1W), while materials like paper, plastic, and air have near-infinite resistance. Increasing circuit resistance reduces the flow of electricity.

SNAP WIRES

The blue snap wires are wires used to connect components. They are used to transport electricity and do not affect circuit performance. They come in different lengths to allow orderly arrangement of connections on the base grid.
SLIDE & PRESS SWITCHES
The slide & press switches (S1 & S2) connect (pressed or “ON”) or disconnect (not pressed or “OFF”) the wires in a circuit. When ON they have no effect on circuit performance. Switches turn on electricity just like a faucet turns on water from a pipe.

Battery Holder (B1)
LAMP A light bulb, such as in the 2.5V lamp (L1), contains a special thin high-resistance wire. When a lot of electricity flows through, this wire gets so hot it glows bright. Voltages above the bulb’s rating can burn out the wire.

Resistors (R1 & R2)
The photoresistor (RP) is a light-sensitive resistor, its value changes from nearly infinite in total darkness to about 1,000W when a bright light shines on it.
Photoresistor (RP)
CAPACITOR The 470mF capacitor (C5) can store electrical pressure (voltage) for a period of time. This storage ability allows it to block stable voltage signals and pass changing ones. Capacitors are used for filtering and delay circuits.

Slide & Press Switches (S1 & S2)

Lamp (L1)

Capacitor (C5)

4

About Your Snap Circuits® Skill Builder 125 Parts

MOTOR

SPEAKER

The motor (M1) converts electricity into mechanical motion. An electric current in the motor will turn the shaft and the motor blades, and the fan blade if it is on the motor.
Motor (M1)
How does electricity turn the shaft in the motor? The answer is magnetism. Electricity is closely related to magnetism, and an electric current flowing in a wire has a magnetic field similar to that of a very, very tiny magnet. Inside the motor is a coil of wire with many loops wrapped around metal plates. This is called an electromagnet. If a large electric current flows through the loops, it will turn ordinary metal into a magnet. The motor shell also has a magnet on it. When electricity flows through the electromagnet, it repels from the magnet on the motor shell and the shaft spins. If the fan is on the motor shaft, then its blades will create airflow.
Power Contacts

The speaker (SP) converts electricity into sound by making mech-anical vibrations. These vibrations create variations in air pressure, which travel across the room. You “hear” sound when your ears feel these air pressure variations. Speaker (SP)
TRANSISTOR
The NPN transistor (Q2) is a component that uses a small electric current to control a large current, and is used in switching, amplifier, and buffering applications. Transistors are easy to miniaturize, and are the main building blocks of integrated circuits including the microprocessor and memory circuits in computers.
NPN Transistor (Q2)
LED

Magnet Shell
Shaft

The red LED (D1) is a light emitting diode and may be thought of as a special one-way 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 an LED, so the current must be limited by other components in the circuit. LEDs block electricity in the “reverse” direction.
LED (D1) Electromagnet

INTEGRATED CIRCUITS (ICs)
Some types of electronic components can be super-miniaturized, allowing many thousands of parts to fit into an area smaller than 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® Skill Builder 125 are actually modules containing specialized sound-generation ICs and other supporting components (resistors, capacitors & 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:

Music IC: TRG (+) HLD

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

(­)
Alarm IC: IN1 IN2

OUT IN3

Music for a few seconds on powerup, then hold HLD to (+) power or touch TRG to (+) power to resume music.
Connections: IN1, IN2, IN3 – control inputs (­) – power return to batteries OUT – output connection

(­)

OUT

Space War IC:

(+)

OUT

Connect control inputs to (+) power to make five alarm sounds, see project 26 for configurations.
Connections: (+) – power from batteries (­) – power return to batteries OUT – output connection IN1, IN2 – control inputs

Connect each control input to

(­) power to sequence through 8

IN1

(­) IN2 sounds.

5

Introduction to Electricity
What is electricity? Nobody really knows. We only know how to produce it, understand its properties, and how to control it. Electricity is the movement of sub-atomic charged particles (called electrons) through a material due to electrical pressure across the material, such as from a battery.
Power sources, such as batteries, push electricity through a circuit, like a pump pushes water through pipes. Wires carry electricity, like pipes carry water. Devices like LEDs, motors, and speakers use the energy in electricity to do things. Switches and transistors control the flow of electricity like valves and faucets control water. Resistors limit the flow of electricity.
The electrical pressure exerted by a battery or other power source is called voltage and is measured in volts (V). Notice the “+” and “­” signs on the battery; these indicate which direction the battery will “pump” the electricity.
The electric current is a measure of how fast electricity is flowing in a wire, just as the water current describes how fast water is flowing in a pipe. It is expressed in amperes (A) or milliamps (mA, 1/1,000 of an ampere).
The “power” of electricity is a measure of how fast energy is moving through a wire. It is a combination of the voltage and current (Power = Voltage x Current). It is expressed in watts (W).
The resistance of a component or circuit represents how much it resists the electrical pressure (voltage) and limits the flow of electric current. The relationship is Voltage = Current x Resistance. When the resistance increases, less current flows. Resistance is measured in ohms (W), or kilo ohms (KW, 1,000 ohms).
Nearly all of the electricity used in our world is produced at enormous generators driven by steam or water pressure. Wires are used to efficiently transport this energy to homes and businesses where it is used. Motors convert the electricity back into mechanical form to drive machinery and appliances. The most important aspect of electricity in our society is that it allows energy to be easily transported over distances.

Note that “distances” includes not just large distances but also tiny distances. Try to imagine a plumbing structure of the same complexity as the circuitry inside a portable radio – it would have to be large because we can’t make water pipes so small. Electricity allows complex designs to be made very small. There are two ways of arranging parts in a circuit, in series or in parallel. Here are examples:
Series Circuit
Parallel Circuit
Placing components in series increases the resistance; highest value dominates. Placing components in parallel decreases the resistance; lowest value dominates. The parts within these series and parallel sub-circuits may be arranged in different ways without changing what the circuit does. Large circuits are made of combinations of smaller series and parallel circuits.

6

DOs and DON’Ts of Building Circuits
After building the circuits given in this booklet, you may wish to experiment 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, capacitor, speaker, integrated circuit, etc.), and wiring paths between them and back. You must be careful not to create “short circuits” (very low- resistance paths across the batteries, see examples at right) 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 OWN. ALWAYS include at least one component that will limit the current through a circuit,
such as the speaker, lamp, ICs (which must be connected properly), motor, photoresistor, or resistors. ALWAYS use the LED, NPN transistor, 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 parts. 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 capacitors so that the “+” side gets the higher voltage.. 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.
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.
WARNING: SHOCK HAZARD – Never connect Snap
! Circuits® Skill Builder 125 to the electrical outlets in your home in any way!
Warning to Snap Circuits® owners:
! Do not connect additional voltage sources from other sets, or you may damage your parts. Contact ELENCO® if you have questions or need guidance.
7

Examples of SHORT CIRCUITS – NEVER DO THESE!!!

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

!
NEVER DO!

This is also a SHORT CIRCUIT.
! NEVER DO!
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!

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. If the motor spins but does not balance the fan, check the black plastic piece on the motor shaft; it should have 3 prongs.

3. 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.
4. 100W resistor (R1), 1KW resistor (R2), and LED (D1): Build Project #11 except initially use the speaker (SP) in place of the resistor, the LED should light. Then, replace the speaker with the 100W resistor; the LED should still light. Then, replace the 100W resistor with the 1KW resistor; the LED should light but not as brightly.
5. Alarm IC (U2): Build Project #19, you should hear a siren. Then place a 3-snap wire between grid locations A1 and C1, the sound is different. Then move the 3-snap from A1-C1 to A3-C3 to hear a third sound.

7. Space war IC (U3) and photoresistor (RP): Build Project #4, both switches (S1 and S2) should change the sound. Then replace the slide switch (S1) with the photoresistor, waving your hand over it should change the sound.
8. NPN transistor (Q2): Build Project #22. When both switches are on, the lamp lights and motor spins. If one switch is off, nothing happens.
9. 470mF capacitor (C5): Build Project #32, then press and release the switch. The LED should go off slowly.
Customer Service
Call toll-free: 800-533-2441 e-mail: help@elenco.com

2. Snap wires: Use this mini-circuit to test the 5-snap and 6-snap wires. The lamp should light. Then test each of the 1-snap, 2-snap, 3-snap, and 4-snap wires by connecting them between the ends of the 5-snap and 6-snap.

6. Music IC (U1): Build Project #18. Turn it on and a tune plays 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 sound resumes for a while.

8

Project #1
Placement Level Numbers

Turn on the Light

Snappy says the lamp contains a special thin high-resistance wire. When a lot of electricity flows through it, it gets so hot it glows bright.

The Snap Circuits® Skill Builder 125 uses electronic blocks that snap onto a clear plastic grid to build different circuits. These blocks have different colors and numbers on them so that you can easily identify them.
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. Install two (2) “AA” batteries (not included) into the battery holder (B1) if you have not done so already.
When you turn on the slide switch (S1), electricity flows from the batteries through the lamp (L1) and back to the batteries through the switch. The switch completes the circuit. The lamp gets bright as electricity flows through it.

Project #2

Up, Up, and Away!

+ Build the circuit shown on the left by placing the

The air is being blown down through the blade parts with a black 1 next to them on the base grid

and the motor rotation locks the fan on the shaft. first. Then, assemble parts marked with a 2. Place

When the motor is turned off, the blade unlocks the glow fan on the motor. New alkaline batteries

from the shaft and is free to act as a propeller are recommended for this project.

and fly through the air. If speed of rotation is too slow, the fan will remain on the motor shaft because it does not have enough lift to propel it.

Turn on the slide switch (S1), wait for the motor to reach full speed, then turn off the switch. The glow fan should rise and float through the air like a flying

saucer. Be careful not to look directly down on the

glow fan when it is spinning.

Placement Level Numbers

!

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.

If the fan doesn’t fly off, then turn the switch on and off several times rapidly when it is at full speed.
The glow fan will glow in the dark. It will glow best after absorbing sunlight for a while. The glow fan is made of plastic, so be careful not to let it get hot enough to melt. The glow looks best in a dimly lit room.

9

Project #3

Super Circuit
Placement Level Numbers

This complex circuit is pictured on the box cover. Use that as a guide to help in building it.

!

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.

The Snap Circuits® Skill Builder 125 uses electronic blocks that snap onto a clear plastic grid to build different circuits. These blocks have different colors and numbers on them so that you can easily identify them.
Build the circuit shown above by placing all the parts with a black 1 next to them on the board first. Then, assemble parts marked with a 2. Then, assemble parts marked with a 3. Then, assemble the part marked with a 4 (the alarm IC (U2), which should be placed directly over the music IC (U1)). Install two (2) “AA” batteries (not included) into the battery holder

(B1). Place the glow fan on the motor (M1).
Turn on the slide switch (S1). You hear music and alarm sounds, and the red LED (D1) lights. The lamp (L1) may light briefly before the red LED turns on. Cover the photoresistor (RP) to change the sound a little.
Push the press switch (S2) to spin the motor and glow fan. Release the press switch when the motor is spinning at full speed. The glow fan should float through the air like a flying saucer. Be careful not to look directly down on the glow fan when it is spinning.

Placement Level
Numbers
If the fan doesn’t fly off, then push and release the press switch several times rapidly when it is at full speed. If the 470mF capacitor (C5) is discharged when you turn on the slide switch, then the lamp will light for a few seconds as the circuit charges up C5. L1 will not light again until C5 is discharged. To discharge C5, remove it from the circuit and place it directly on the 4-snap wire for an instant, then move it back to its normal spot in the circuit.
10

Project #4

Space War
Build the circuit shown on the left, which uses the space war integrated circuit. Activate it by flipping the slide switch (S1) or pressing the press switch (S2), do both several times and in combination. You will hear an exciting range of sounds, as if a space war is raging!
The space war IC (U3) is a super-miniaturized electronic circuit that can play a variety of cool sounds stored in it by using just a few extra components.
In movie studios, technicians are paid to insert these sounds at the precise instant a gun is fired. Try making your sound occur at the same time an object hits the floor. It is not as easy as it sounds.
The Space War, Alarm, and Music ICs contain specialized ICs combined with other electrical components (resistors, capacitors, transistors) designed to produce various cool sounds and music.

Project #5 Loud in Light
Use the circuit from Project #4 above, but replace the slide switch (S1) with the photoresistor (RP). The circuit immediately makes noise. Try turning it off. If you experiment, then you can see that the only ways to turn it off are to cover the photoresistor, or to turn off the lights in the room (if the room is dark). Since light is used to turn on the circuit, you might say it is a “light switch”.
The photoresistor contains material that changes its resistance when it is exposed to light; as it gets more light, the resistance of the photoresistor decreases. Parts like this are used in a number of ways that affect our lives. For example, you may have streetlights in your neighborhood that turn on when it starts getting dark and turn off in the morning.
11

Project #6 Paper Player
Use the same circuit as for Project #5. Find a piece of white paper that has a lot of large black or dark areas on it, and slowly slide it over the photosensitive resistor. You may need to shine a flashlight over the paper. You should hear the sound pattern constantly changing, as the white and dark areas of the paper control the light to the photosensitive resistance. You can also try the pattern below or something similar to it.

Project #7

• Project #8

Stick Around Saucer

Build the circuit shown on the left which is the same as the circuit in Project #2 but with the motor part reversed. Place the glow fan on the motor.
Turn on the slide switch (S1), wait for the motor to reach full speed, then turn off the switch. This time, the glow fan does not fly because the fan is now rotating in the opposite direction such that the airflow is pushing the fan downward.

!

WARNING: Moving parts. Do not touch the fan or motor during operation.

Rotate & Roar
Build the circuit shown on the left, but leave the fan off the motor (M1). When you turn on the slide switch (S1), the music may play for a short time and then stop. After the music has stopped, spin the motor with your fingers. The music should play again for a short time, then stop.
Now replace the 100W resistor (R1) with a 3-snap wire, and notice how the sound is affected.
In this project, you changed the amount of current that goes through the speaker (SP) and increased the sound output of the speaker.
Resistors are used throughout electronics to limit the amount of current that flows.

12

Project #9

Spin & Dim

The parts are arranged as a series circuit. You can swap the locations of any of the parts without affecting circuit operation.

Build the circuit shown on the left.
When you turn on 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 tries to keep a body at rest from moving and tries to keep a moving object from stopping.
The lamp helps protect the motor from getting the full voltage when the switch is turned on. 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.

!

WARNING: Moving parts. Do not touch the fan or motor during operation.

Project #10

Balanced Buddies

Build the circuit shown on the left.

The parts are arranged as

When you turn on the slide switch (S1), both the fan and the lamp

a parallel circuit. Parallel circuits are often used in

(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

residential homes so that

motor (M1). The motor should start a little faster than in Project #9.

turning on one device

doesn’t limit the current to other devices.

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).

!

WARNING: Moving parts. Do not touch the fan or motor during operation.

13

Project #11

• Project #12

The Diode Dude
Build the circuit shown on the left. When you turn on the slide switch (S1), current flows from the batteries (B1) through the switch, through the 100W resistor (R1), through the LED (D1, light emitting diode) and back to the battery. The turned on 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?
One Way Works
Rebuild the circuit used in Project #11 but put the LED in as shown on the left. This time when you turn on the slide switch (S1), current does not flow from the batteries (B1) through the 100W resistor (R1) or through the LED (D1), and hence the LED does not light up. This is because the LED is in backwards. The LED is like a check valve that lets current flow in only one direction (into the + end and out the other end).
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.
14

Project #13 Project #14
15

Clippy the Conductor
Rebuild the circuit from Project #11 but leave the slide switch (S1) out as shown on the left. When you place a paper clip across the terminals as shown in the picture on the left, current flows from the batteries (B1) through the 100W 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 is too high of a resistance to allow enough current to flow to light the LED. If the voltage, which is electrical pressure, was 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. Materials that make the LED bright pass electricity easily, and are called conductors. Most metals are good conductors, and copper is used in most house wiring. Materials that block the flow of electricity are called insulators. Plastic, paper and air are insulators.
Nifty Noises
Build the circuit shown. Turn it on, press the press switch (S2) several times, and wave your hand over the photoresistor (RP) to hear all the sound combinations. You can make the sound from the alarm IC (U2) louder by replacing the 100W resistor (R1) with the 2.5V lamp (L1).
A photoresistor is a light-controlled variable resistor. The resistance of the photoresistor decreases with increasing light intensity.

Project #15

Mumbling Motor
Place the fan on the motor (M1). Press the press switch (S2) and listen to the motor. Why does the motor make sound?
If you replace the motor with the 2.5V lamp (L1), then it will only make noise when the lamp is turned ON or OFF.

A motor uses magnetism to convert electrical energy into mechanical spinning motion. As the motor shaft spins around it connects / disconnects several sets of electrical contacts to give the best magnetic properties. As these contacts are switched, an electrical disturbance is created, which the speaker (SP) converts into sound.

!

WARNING: Moving parts. Do not touch the fan or motor during operation.

Project #16

Hi-Low Fan

!

WARNING: Moving parts. Do not

touch the fan or motor

during operation.

Build the circuit shown on the left.
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.
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Project #17 Project #18
17

Magical Music
Build the circuit shown on the left. When you turn on the slide switch (S1), the music integrated circuit (U1) may start playing one song then stop. Each time you press the press switch “doorbell button” (S2) the song will play again and stop. Even if you let go of the press switch (S2), the integrated circuit keeps the song playing until it has reached the end of the song.
Musical integrated circuits are used to entertain young children in many of the toys and chairs made to hold infants. If the music is replaced with words, the child can also learn while they are entertained. Because of great advances in miniaturization, many songs are stored in a circuit no bigger than a pinhead.
Press & Play
Modify the circuit used in Project #17 to look like the one shown on the left. When you turn on the slide switch (S1), the music integrated circuit (U1) may start playing one song then stop. The song will be much louder than in the previous project because it is now being used as an alarm. Each time you press the press switch “alarm button” (S2) after the song stops playing, the song will play again, but only while you hold the button down.
Having no resistor in series with the speaker allows more current to flow through the speaker producing a louder sound.

Project #19

Simple Siren
Build the circuit shown on the left. When you turn on the slide switch (S1), the integrated circuit (U2) should start sounding a very loud alarm sound. This integrated circuit is designed to sweep through all the frequencies so even hard of hearing people can be warned by the alarm.
If the alarm sound in this circuit was passed through an amplifier and installed into a police car, it would also serve as a good police siren.

Project #20

Sporadic Sounds
Build the circuit shown on the left and turn it on. The lamp (L1) alternates between being on and off while the speaker (SP) alternates between two musical tones … like someone is flipping a switch, but at a very consistent rate. Periodic signals like this are very important in electronics.
Periodic electrical signals are used for things like flashing yellow lights or sometimes in consumer devices to indicate batteries are low.

Project #21 Blinking Double Flashlight
In the circuit at left, replace the speaker (SP) with an LED (D1). Make sure you connect the LED with the positive (+) side on A5, not U1. The lamp (L1) alternates between being on and off while the LED alternates between being dimmer and brighter.

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Project #22 Transistor Control

!

WARNING: Moving parts. Do not touch the fan or motor

during operation.

Place the fan on the motor (M1) and turn on the slide switch (S1) – nothing happens. Push the press switch (S2), the lamp lights and the motor spins.
The NPN transistor (Q2) uses the lamp current to control the motor current. A small current through the lamp branch creates a large current through the motor branch. They combine in the transistor and leave through the 3-snap branch.

Project #24 Stop & Shine

Compare this circuit to Project #23. It works in a similar way, but the motor does not spin even though the lamp is bright. But the lamp is not as bright here as in Project #23.
The currents in the motor branch and 3-snap branch are combined into the lamp branch. Since the 3-snap has no resistance, the current through its branch will be much larger than the motor branch current.
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Project #23 Slow & Bright

!

WARNING: Moving parts. Do not touch the fan or motor

during operation.

Compare this circuit to Project #22. It works the same way, but the lamp is brighter here and the motor is slower.
This time the NPN transistor (Q2) uses the motor current to control the lamp current. A current through the motor branch creates a larger current through the lamp branch. They combine in the transistor and leave through the 3-snap branch.

Project #25 Murky Motor

!

WARNING: Moving parts. Do not touch the fan or motor

during operation.

Compare this circuit to Project #24. It works in a similar way, the lamp is off but the motor spins. But the motor does not spin as fast as in Project

22.

The currents in the lamp branch and 3-snap branch are combined into the motor branch. Since the 3-snap has no resistance, the current through its branch will be much larger than the lamp branch current.

Project #26 Project #31

Motor Magic
This circuit is controlled by spinning the motor (M1) with your hands. Turn on the switch. A police siren is heard and then stops. Spin the motor and it will play again. Note, however, that music can be heard faintly in the background of the siren.
Project #27 Spin & Shoot
Modify the last circuit by connecting points X & Y with the 2.5V lamp (L1). The circuit works the same way but now it sounds like a machine gun.
Project #28 Spin Out Siren
Now remove the connection between X & Y and then make a connection between T & U with the 2.5V lamp (L1). The circuit works the same way but now it sounds like a fire engine.
Project #29 Whirl Out Warning
Now remove the connection between T & U and then make a connection between U & Z. The circuit works the same way but now it sounds like an ambulance.
Project #30 Turn a Tune
Now remove the connections between U & Z and between V & W, then make a connection between T & U. The circuit works the same way but now it sounds like a familiar song but with static.
Spin & Stop
Place the fan on the motor and turn on the slide switch (S1). The motor spins briefly as the 470F capacitor (C5) charges up. Turn off the slide switch and push the press switch (S2) to discharge the capacitor and reset the circuit. You can bypass the capacitor by pushing the press switch while the slide switch is on. This lets the motor spin at full speed and also lights the lamp.
WARNING: Moving parts. Do not touch the fan or
! motor during operation.
20

Project #32

Lingering Light
Build the circuit and press the switch (S2). You see that the LED (D1) turns off slowly after you release the switch. This delay in turning off the LED is caused by the 470mF capacitor (C5).
Capacitors can store electricity and are used to delay changes in voltage. They can block unchanging voltages while passing fast-changing voltages.

Project #33
21

Auto-Off Day Light
Cover the photoresistor (RP) and turn on the slide switch (S1). The LED (D1) is bright, but it will very slowly get dimmer and dimmer as the 470mF capacitor (C5) charges up. If you turn the slide switch (S1) off and back on after the light goes out it will NOT come on again. Push the press switch (S2) to discharge the capacitor and reset the circuit.
If you uncover the photoresistor and to let light shine on it, then the LED will get dark quickly. The photoresistor has much lower resistance with light on it, and this lower resistance allows the capacitor to charge up faster.
This circuit would make a good day light. It would quickly turn off the lights when you opened the shades and let the sunlight in.

Project #34 Little R Rules
Turn on either or both switches and compare the LED brightness. This circuit has the 100W and 1KW resistors (R1 and R2) arranged in parallel. You can see that the smaller 100W resistor controls the brightness in this arrangement.
Project #36

Project #35 Big R Rules
Turn on either or both switches and compare the LED brightness. This circuit has the 100W resistor (R1), the 1KW resistor (R2), and the photoresistor (RP) arranged in series. You can see that the larger photoresistor limits the brightness in this arrangement (the resistance of the photoresistor will be much higher than the others, unless the light is very bright).
Using Parts as Conductors
Turn on the slide switch (S1) and push the press switch (S2), you hear a machine gun sound (with music in the background). Thoroughly cover the photoresistor with your hand and the sound becomes a siren. After a while the sound will stop, push the press switch and it resumes.
Note that the LED (D1) lights, but the lamp (L1) does not light and the motor (M1) does not spin. Electricity is flowing through the lamp and motor, but not enough to turn them on. So in this circuit they are acting like 3-snap wires. You could replace D1 or L1 with a 3-snap and the circuit would work the same.

22

Project #37
Spin Draw
Setup: Cut out a circular piece of thin cardboard from the back of an old spiral notebook or note pad. Use the fan blade as a guide. Place the fan on the cardboard and trace around it with a pencil or pen. Cut the cardboard out with scissors and tape it to the fan blade. Do the same thing with a piece of white paper, but tape the paper on top of the cardboard so it can be removed easily later.
Drawing: To make a ring drawing obtain some thin and thick marking pens as drawing tools. Spin the paper by pressing and holding press switch (S2) down. Press the marker on the paper to form rings. To make spiral drawings, release press switch (S2) and as the motor approaches a slow speed move the marker from the inside outward quickly.
Change the colors often and avoid using too much black to get hypnotic effects. Another method is to make colorful shapes on the disc then spin the disc and watch them blend into each other. When certain speeds are reached under fluorescent lights without electronic ballasts, the strobe principle shown in another project will produce strange effects and backward movement. Make a wheel with different colored spokes to see this strange effect. Adding more spokes and removing spokes will give different effects at different motor speeds.

Project #38

Singing Motor
Turn on the switch and the motor spins (you may need to give it a push with your finger to get it started). The sounds from the IC are used to drive the motor. Because the motor uses magnets and a coil of wire similar to a speaker, you may even hear the space war sounds coming faintly from the motor.
The motor has a coil and a magnet similar to the speaker. An electrical signal in the coil creates a magnetic field, which makes the shaft spin. Normally the motor is used with a stable electrical signal, but in this project it is used with a changing signal from the space war IC. This creates mechanical vibrations, which create air pressure variations that sound like the speaker does, though not as efficiently.

23

Project #39 Project #40

Switch & Store
Turn on the slide switch (S1) and the LED (D1) lights; it will not be very bright so turn off the room lights or hold your fingers around it to see it better. Push the press switch (S2) several times slowly; the LED and lamp (L1) go on and off. Push the press switch many times quickly – the lamp still goes on and off but the LED stays on. Next, remove the 470mF capacitor (C5) from the circuit – the LED goes on and off now. Why? Pressing the switch quickly simulates a changing voltage, which turns the LED on and off. The 470mF capacitor can store electricity, and it combines with the NPN transistor (Q2) to simulate a rectifier. This rectifier converts the changing voltage at the press switch into a constant voltage, which keeps the LED on. You can replace the 1KW resistor (R2) with the 100W resistor (R1). This makes the LED a little brighter but you have to press the switch faster to keep it on, because the lower resistance drains the capacitor faster.
The electricity supplied to your home by your electric company is actually a changing voltage. Many electronic products use rectifier circuits to convert this into a constant voltage like a battery provides.
Crazy Combo
Build the circuit shown. Turn it on, press the press switch (S2) several times, and wave your hand over the photoresistor to hear all the sound combinations. You can make the sound from the music IC louder by replacing the 100W resistor (R1) with the 2.5V lamp (L1).
The music and space war ICs (U1 and U3) 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.
-402-4

Project #41 Project #42
25

Alien Alarm
Build the circuit shown on the left and turn on the slide switch (S1). Press and hold the press switch (S2) to make the lamp (L1) brighter.
The speaker uses electromagnetism to create changes in air pressure, which your ears feel and interpret as sound. Think of the speaker as creating pressure waves in the air just like waves in a pool. You only see waves in the pool when you disturb the water, so the speaker only makes sound when the voltage changes.
Electron Warehouse
Build the circuit, then connect points B & C (use a 2-snap wire) for a moment. Nothing appears to happen, but you just filled up the 470mF capacitor (C5) with electricity. Now disconnect B & C and instead touch a connection between A & B. The red LED (D1) will be lit and then go out after a few seconds as the electricity you stored in it is discharged through the LED and resistor (R2).
Notice that a capacitor is not very efficient at storing electricity – compare how long the 470mF capacitor kept the LED lit with how your batteries run all of your projects! That is because a capacitor stores electrical energy while a battery stores chemical energy.

Project #43 Project #44

Fun with the Alarm IC
Place the fan on the motor (M1) and turn on the slide switch (S1). The lamp (L1) lights, the motor spins, and you hear a machine gun sound (with very faint music in background). Thoroughly cover the photoresistor (RP) with your hand and the sound becomes a siren. After a while the sound will stop, hold down the press switch (S2) and the sound resumes.
Photoresistors can be used to control many devices such as street lights, clock radio alarms, night lights, etc.

!

WARNING: Moving parts. Do not touch the fan or motor during operation.

Dancing Motor
Place the fan on the motor (M1) and turn on the slide switch (S1). A song is heard and the fan spins unevenly. The fan speed is being controlled by the music IC (U1). Now push the press switch (S2) to control the motor directly, and the motor spins much faster.
WARNING:
! Moving parts. Do not
touch the fan or motor during operation.

Project #45
Musical Light
Use the circuit in Project #44. Replace the motor (M1) with the 2.5V lamp (L1). Now the music IC (U1) and press switch (S2) control the lamp brightness.
26

Project #46 Project #47
27

Music Alarm Combo
Build the circuit shown and then place the alarm IC (U2) directly over the music IC (U1), resting on the three 1-snaps. Turn on the slide switch (S1) and you will hear a siren and music together. After a few seconds, covering the photoresistor (RP) will stop the music (but the siren continues).

Sing & Fling

In the circuit, the outputs from the alarm and music ICs are connected together. Build the circuit shown and then place the alarm IC (U2) directly over the music IC (U1), resting on two 1-snaps and a 2-snap. Turn on the slide switch (S1) and you will hear a siren and music together while the lamp (L1) varies in brightness. Push the press switch (S2) and the fan spins, while the sound may not be as loud. The fan may rise into the air when you release the switch.

!

WARNING: Moving parts. Do not touch the fan or motor during operation.

! WARNING: Do not lean over the motor.

Project #48 Project #49

Stay or Blink
Build the circuit and turn on the slide switch (S1). The LED (D1) is dim, and is actually flashing very quickly, and the speaker (SP) makes a siren sound. Now push the press switch (S2) to connect the 470mF capacitor (C5) to the circuit. The LED is brighter and stops flashing. The signal from the alarm IC (U2) to the speaker is a changing voltage, which is why the LED was flashing. The 470mF capacitor can store electricity, and it combines with the NPN transistor (Q2) to make a rectifier. A rectifier converts a changing voltage into a constant voltage, so the LED stays on constantly instead of flashing.
Rectifiers are used to convert the AC voltage from the outlets in your house to a DC voltage used by most of the devices in your house.
Slow Siren Changer
Turn on the slide switch (S1) and you hear a siren sound. Now hold down the press switch (S2) until the sound becomes a fire engine sound. This delay is due to the 470mF capacitor (C5) charging up and is controlled by the photoresistor (RP). If there is bright light on the photoresistor, then the delay will be only a few seconds. Release the press switch and after a while the sound will be a siren again. The capacitor slowly discharges through the NPN transistor (Q2).
This circuit demonstrates how capacitors store up energy when S2 is pressed, and then discharge energy when S2 is released.
28

Project #50 Project #51
29

Touch of Light
Build the circuit on the left. You’re probably wondering how it can work, since one of the points on the NPN transistor (Q2) is unconnected. It can’t, but there is another component that isn’t shown. That component is you. Touch points X & Y with your fingers. The LED (D1) may be dimly lit. The problem is your fingers aren’t making a good enough electrical contact with the metal. Wet your fingers with water or saliva and touch the points again. The LED should be very bright now. Think of this circuit as a touch lamp since when you touch it, the LED lights. You may have seen such a lamp in the store or already have one in your home.
Change & Charge
Turn the slide switch (S1) on and connect points A & B with a 2-snap wire. The LED (D1) will flash and the 470mF capacitor (C5) will be charged with electricity. The electricity is now stored in the capacitor. Disconnect points A & B. Connect points B & C and there will be a flash from the 2.5V lamp (L1). The capacitor discharges through the resistor to the base of the NPN transistor (Q2). The positive current turns on the transistor like a switch, connecting the lamp to the negative (­) side of the batteries (B1). The light will go out after the capacitor discharges, because there is no more current at the base of the transistor.

Project #52
Project #53
Go to https://shop.elenco.com/ consumers/skillbuilder.html to download projects 58-125

Glow & Go
Build the circuit to the left. Turn on the slide switch (S1). The alarm will sound, as long as light is present. Slowly cover the photoresistor (RP), and the volume goes down. If you turn off the lights, the alarm will stop. The amount of light changes the resistance of the photoresistor (less light means more resistance). The photoresistor and NPN transistor (Q2) act like a dimmer switch, adjusting the voltage applied to the alarm.
This type of circuit is used in alarm systems to detect light. If an intruder turned on a light or hit the sensor with a flashlight beam, the alarm would trigger and probably force the intruder to leave.

Shine On Siren

Cover the photoresistor (RP) and turn on the switch (S1). A police siren is heard for a while and stops, then you can control it by covering or uncovering the photoresistor.

Project #54 Shooting Sounds

Modify Project #53 by connecting points X & Y. The circuit works the same way but now it sounds like a machine gun.
Project #55 Song & Siren

Now remove the connection between X & Y and then make a connection between T & U. It now sounds like a fire engine.
Project #56 Ambulance Melody

Now remove the connection between T & U and then make a connection between U & Z. It now sounds like an ambulance.

Project #57 Static Song

Now remove the connections between U & Z and between V & W, then

make a connection between T & U. It now sounds like a familiar song but

with static.

30

SB-125 Block Layout

Go to https://shop.elenco.com/ consumers/skillbuilder.html to download projects 58-125

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free 800-533-2441 or e-mail us at: help@elenco.com | 150 Carpenter Ave. Wheeling, IL 60090 U.S.A
Note: A complete parts list is on page 2 in this manual.

31

References

• elenco.com
• Elenco-Home: Consumers

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