Electronics for Kids: Play with Simple Circuits and Experiment with Electricity
How to Use an LED Correctly 76 How to Write Small Values 77 Protecting Your LED with a Resistor 77 Calculating the Resistance You Need 78 Project 8 Powering an LED 78 Shopping List 79 Step 1 Twist the Resistor and LED 79 Step 2 Wire the Battery Clip 80 Step 3 Let There Be Light 80 Step 4 What If the LED Doesn’t Work 81 Building Circuits on a Breadboard 81 How to Connect Components and Wires 81 Wires to Use on a Breadboard 83 Project 9 Your First Breadboard Circuit 84 Shopping List 84 Step 1 Place the Resistor 85 Step 2 Place the LED 85 Step 3 Place the Battery Clip 86 Step 4 What If the LED Doesn’t Work 87 What’s Next 87 5 Blinking a Light for the First Time 89 Meet the Capacitor 90 How Capacitors Work 90 Polarized and Nonpolarized Capacitors 91 Capacitor Values 92 Project 10 Test a Capacitor 92 Shopping List 93 Step 1 Start with the LED Circuit 94 Step 2 Add the Capacitor 94 Step 3 Charge the Capacitor 95 Step 4 Use the Capacitor to Light the LED 95 Step 5 What If the Circuit Doesn’t Work 95 Describing Circuits with Symbols 95 Meet the Relay 97 Using the Relay to Blink a Light 99 Slowing Down the Blinking 100 Project 11 Blink a Light 101 Shopping List 102 Step 1 Identify the Relay Pins 103 Step 2 Make the Relay Switch Fast 104 xii CONTENTS IN DETAIL
Step 3 Make the Relay Stay On Longer 105 Step 4 Make the Relay Stay Off Longer 106 Step 5 Add the LED and Resistor 106 Step 6 What If the LED Won’t Blink 108 Try It Out Make Your Intruder Alarm More Effective 108 What’s Next 109 6 111 Let’s Solder How to Solder 112 Soldering Safety Tips 113 Heat the Soldering Iron 114 Clean the Soldering Iron Tip 115 Tin the Soldering Iron Tip 115 Heat Both the Pin and the Pad 115 Add Solder 116 Remove the Soldering Iron 116 Watch Out for Bad Solder Joints 117 Project 12 Solder Your First LED Circuit 118 Shopping List 118 Tools 119 Step 1 Place the Components 120 Step 2 Bend the Component Legs 120 How to Read the Circuit Board Illustrations 121 Step 3 Heat and Clean the Soldering Iron 122 Step 4 Solder the Resistor and LED 122 Step 5 Trim the Legs 122 Step 6 Solder the Battery Clip 123 Step 7 Let There Be Light 124 Step 8 What If the Soldered LED Circuit Doesn’t Work 124 Oops How Do I Remove a Soldered Component 125 Project 13 Desolder the Battery Clip 126 Shopping List 126 Tools 126 Step 1 Heat the Soldering Iron 127 Step 2 Place the Solder Wick on the Solder Joint 127 Step 3 Heat the Solder Joint and the Solder Wick 128 Step 4 Trim the Used Solder Wick 128 Step 5 Remove the Other Battery Clip Wire 129 Try It Out Solder More Stuff 129 What’s Next 130 CONTENTS IN DETAIL xiii
7 Controlling Things with Electricity 131 Meet the Transistor 132 Why Use a Transistor 133 How the Transistor Works 134 Controlling an LED with a Transistor 135 Project 14 Build a Circuit that Senses Touch 136 Shopping List 138 Tools 139 Step 1 Place Components on the Prototyping Board 140 Step 2 Check Your Component Placement 140 Step 3 Solder the Components and Trim Excess Legs 140 Step 4 Solder the Touch Pad 141 Step 5 Power It Up 142 Step 6 Test the Sensor 142 Step 7 What If the Touch Sensor Doesn’t Work 142 Try It Out Can the Touch Sensor Detect Different Touches 144 Resistors That Can Change Value 144 Meet the Potentiometer 145 Meet the Photoresistor 146 Dividing a Voltage with Resistors 146 What Does a Voltage Divider Look Like 147 Calculating the Voltage from a Voltage Divider 147 How a Voltage Divider Can Help Measure Light 148 Project 15 Build a Sunrise Wake-Up Alarm 148 Shopping List 150 Tools 151 Step 1 Place Components on the Prototyping Board 152 Step 2 Solder the Components and Trim the Legs 152 Step 3 Add the Buzzer to the Board 153 Step 4 Make the Remaining Connections with Wires 154 Step 5 Add the Battery Clip to the Board 155 Step 6 Set a Wake-Up Call 156 Step 7 What If There’s No Sound 156 Try It Out Temperature-Controlled Fan 157 What’s Next 159 8 Building a Musical Instrument 161 Meet the Integrated Circuit 162 ICs and Datasheets 162 How to Make Sound with Electricity 163 xiv CONTENTS IN DETAIL
Sounds That Humans Can Hear 164 Meet the 555 Timer 164 Powering an IC 165 How to Set the Output Speed of the 555 Timer 166 Project 16 Make Your Own Sound with the 555 Timer 167 Shopping List 169 Step 1 Place the 555 Timer on the Breadboard 170 Step 2 Set the Frequency 171 Step 3 Connect the Speaker and Coupling Capacitor 171 Step 4 Connect the Power and Reset Pins 173 Step 5 Make Some Sound 173 Step 6 What If There’s No Sound 174 Checking Connections as a Team 174 Turning an Annoying Beep into Music 175 Project 17 An Instrument That Beeps and Boops 175 Shopping List 177 Step 1 Connect the 555 Timer and the Capacitors 178 Step 2 Connect Jumper Wires 179 Step 3 Connect the Note Controller and Resistor 179 Step 4 Add the On Button 180 Step 5 Add the Loudspeaker 181 Step 6 Play Some Music 182 Step 7 What If the Instrument Doesn’t Work 183 Try It Out Make a Motion-Controlled Instrument 183 What’s Next 184 Part 3 The Digital World 9 How Circuits Understand Ones and Zeros 187 Ones and Zeros as Voltages 188 Meet the Binary Number System 188 Project 18 Convert from Binary to Decimal 190 Tools 190 Step 1 Write It Down on Paper 190 Step 2 Write the Position Values 191 Step 3 Find the Value of Each Digit 191 Step 4 Add the Numbers 192 Try It Out Transform More Binary Numbers 192 Bits and Bytes 193 Numbers Can Be Anything 193 CONTENTS IN DETAIL xv
