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Signal build

AM 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 works by hiding sound inside a much faster wave. The carrier wave is the thing a radio can tune to; the audio rides along by changing the carrier height.

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This build demonstrates resonance and modulation. A tuned system selects a carrier frequency, then the transmitter changes the amplitude so a nearby AM radio can recover the voice or music from the envelope.

f_{0} = \frac{1}{2 π L C}

An LC resonator naturally favors one radio frequency.

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

Amplitude modulation changes the carrier strength according to the audio signal.

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.

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

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

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Use with an existing phone or audio player.

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Preferred Apple laptop option for coding, editing, and project-control work.

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ELEGOO UNO R3 Board ATmega328P with USB Cable(Arduino-Compatible) for Arduino

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Arduino Uno REV3 Microcontroller Board

Use the exact board/pinout required by the project; clones may differ.

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

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Project files

Prints, kits, and downloads.

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

Coming soon

Contact

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