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Signal build

AM Radio Transmitter

Start with the video, then use the science notes and recommended parts below to follow the idea behind the build.

Radio & soundBuildRadio

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How it works

What this project is testing.

AM radio sends sound by changing the height of a steady radio wave. The fast wave does the traveling; the slower audio signal shapes its envelope.

Read more

This project demonstrates modulation: a nearby receiver can ignore most of the high-speed carrier and follow the changing envelope to recover the original sound.

s (t) = A [1 + m x (t)] cos (2 π f_{c} t)

The audio signal x(t) changes the carrier amplitude while the carrier frequency stays centered at f_c.

Recommended parts

Products used in this project.

Affiliate links may earn Keystone Science a commission. Match ratings, values, sizes, polarity, and safety requirements to your own build before buying.

Jesverty DC Power Supply Variable, 0-30V 0-10A Adjustable Switching DC Regulated Bench Power Supply with High Precision 4-Dig

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Variable DC Bench Power Supply, 30V 10A Adjustable Regulated Supply

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Amazon Basics 8-Pack 9V Long-Lasting Alkaline Batteries for Smoke Detector, Electronics & Audio, Reliable, 5-Year Shelf Life

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Amazon Basics 8-Pack 9V Long-Lasting Alkaline Batteries

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General electronics battery pick; choose AA/AAA variants when the circuit calls for them.

Rigol Digital Oscilloscope DS1054Z 50 MHz 4-Ch 1 GSa/s 24 Mpts 30,000 wfms/s UltraVision 7" 800x480 Intensity Display, 60,000-Frame Record/Playback, Serial Decode UART I2C SPI for Debug & Education

oscilloscopetest equipment

Rigol DS1054Z Digital Oscilloscope, 50 MHz, 4 Channel, 1 GSa/s

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Good bench choice; budget scope alternatives may be cheaper but less durable.

Auto Ranging Digital Multimeter TRMS 6000 with Battery Alligator Clips Test Leads AC/DC Voltage/Account,Voltage Alert, Amp/Ohm/Volt Multi Tester/Diode

multimetertest equipment

Auto-Ranging Digital Multimeter TRMS 6000 with Battery, Alligator Clips, and Test Leads

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Goupchn Universal P6100 Oscilloscope Clip Probes 100MHz with Accessories Kit 1X 10X 2 Pack

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Goupchn Universal P6100 Oscilloscope Clip Probes, 100MHz, 1X/10X, 2 Pack

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YIHUA 926 III 60W Digital Display Soldering Iron Station Kit w 2 Helping Hands, 6 Extra Iron Tips, Lead-Free Solder, Solder Sucker, S/S Tweezers, °C/ºF Conversion, Auto Sleep & Calibration Support

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YIHUA 926 III 60W Digital Display Soldering Iron Station Kit

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BOJACK 3 Values 130 Pcs Solderless Breadboard 4 Pcs 830 Tie Points & 400 Tie Points & 126 Pcs Flexible Breadboard Jumper Wires

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EDGELEC 120pcs Breadboard Jumper Wires 20cm Wire Length Optional Dupont Cable Assorted Kit Male to Female Multicolored Ribbon Cables

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BOJACK 24Value 630pcs Aluminum Electrolytic Capacitor Assortment Box Kit Range 0.1uF－1000uF

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BOJACK 10 Values 250 Pcs A1015 BC327 BC337 C1815 S8050 S8550 2N2222 2N2907 2N3904 2N3906 PNP NPN Power General Purpose Transistors Assortment Kit

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BOJACK 12 Values 120 Pcs Opamp Timer Darlington Phototcoupler LM324 LM339 ULN2003AN ULN2803APG LM358P LM386 LM393 NE5532P NE555P UA741CN JRC4558D PC817 IC Assortment Kit

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150 Pcs 15 Value 100 ohm- 2M ohm Trimpot Variable Resistor 6mm Potentiometer Assortment Kit

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BOJACK 20 Values 200 Pcs Inductor 10 uH to 10 mH 1 W Color Ring Inductor 1 Watt Assortment Kit

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20 Values 200 Pcs Inductor Assortment Kit, 1uH to 4.7mH, 0.5W Color Ring Inductors

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12V 2A Power Supply, AC 120V to DC12V 5.5x2.1mm Jack Converter, 12 Volt LED Driver 24W Adapter Transformer for Strip Lights, Surveillance Cameras, External HDD, Monitor, CCTV (Pack of 1)

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12V 2A Power Supply, AC 120V to DC12V 5.5x2.1mm Adapter Transformer

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General low-voltage transformer/adapter pick; match voltage/current and connector to the circuit.

CQRobot Speaker 3 Watt 8 Ohm Compatible with Arduino Motherboard, JST-PH2.0 Interface. It is Ideal for a Variety of Small Electronic Projects.

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CQRobot 3 Watt 8 Ohm Speaker for Arduino and Small Electronics Projects

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Syncwire 3.5mm Nylon Braided Aux Cable (3.3ft/1m,Hi-Fi Sound), Audio Auxiliary Input Adapter Male to Male Cord for Headphones, Car, Home Stereos, Speaker, iPhone, iPad, iPod, Echo & More – Black

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3.5mm Nylon Braided Aux Cable, Male to Male, 3.3ft

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Use with an existing phone or audio player.

Panasonic Portable AM/FM Radio, Battery Operated Analog Radio, AC Powered, Silver (RF-2400D)

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Panasonic RF-2400D Portable AM/FM Radio, Battery Operated or AC Powered

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E-outstanding 1 Pair AM FM Radio Universal Antenna, 62.5cm 24.6" Length 4 Section Telescopic Stainless Steel Replacement Antenna Aerial for Radio TV

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E-outstanding 1 Pair AM/FM Radio Universal Telescopic Stainless Steel Replacement Antenna

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Theefun Plasma Ball 8 Inch Plasma Globe Lamp

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8 Inch Plasma Ball, Touch and Sound Sensitive Plasma Globe Lamp

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TOSHIBA EM131A5C-BS Countertop Microwave Ovens 1.2 Cu Ft, 12.4" Removable Turntable Smart Humidity Sensor 12 Auto Menus Mute Function ECO Mode Easy Clean Interior Black Color 1000W

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Toshiba EM131A5C-BS Countertop Microwave Oven, 1.2 Cu Ft, 1000W

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Recommend only as an appliance; do not encourage buying a working microwave for disassembly. Review requirements and safety guidance before buying.

BOJACK 1000 Pcs 25 Values Resistor Kit 1 Ohm-1M Ohm with 5% 1/4W Carbon Film Resistors Assortment

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BOJACK 1000 Pcs 25-Value 1/4W Carbon Film Resistor Assortment Kit, 1 ohm-1M ohm

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BOJACK 12 Values 60 Pcs Quartz Crystal Oscillator 4 MHz, 4.096 MHz, 6 MHz, 8 MHz, 10 MHz, 11.0592 MHz, 12 MHz, 16 MHz, 20 MHz

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1 MHz Crystal Oscillator 5V, 5 Pack

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Confirm frequency and supply voltage before buying. Review requirements and safety guidance before buying.

AEDIKO 10pcs EE-14 Audio Transformer High Efficiency Audio Isolation Transformers 1300 : 8 Ohm for Voltage Amplification and Power Output

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EE-14 Audio Transformers, 1300 Ohm to 8 Ohm, Pack of 5

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Confirm transformer ratio and impedance before buying. Review requirements and safety guidance before buying.

ShillehTek Pre-soldered 3.5mm Stereo Audio Jack Breakout Board – TRRS Headphone/Video Jack Module for Arduino, Raspberry Pi,

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3.5mm Stereo Audio Jack Breakout Board with Screw Terminal

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Functional breakout pick; verify mono/stereo wiring and connector style. Review requirements and safety guidance before buying.

ElectroCookie Large PCB Prototype Board Kit Solderable Breadboards for Electronics Projects Compatible for DIY Arduino Soldering Projects, Gold-Plated (6 Multi-Pack, Blue)

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Prints, kits, and downloads.

Diagrams, printable files, kits, or companion downloads will appear here when they are ready to use.

Coming soon

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