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Electricity

Battery powered phone charger!

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

ElectricityBuildElectronics

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How it works

What this project is testing.

A phone charger is really a controlled energy handoff: a battery has stored chemical energy, but the phone wants a steady USB-friendly voltage.

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This project demonstrates voltage regulation, current limits, and the heat losses that show up when portable power is converted into something a device can safely use.

P = V I

Electrical power depends on both voltage and current.

η = \frac{P _{o u t}}{P _{in}}

Efficiency shows how much battery power reaches the phone instead of becoming heat.

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.

DEVMO DC 3V-6V to 400kV 400000V Boost Step-up Power Module High-Voltage Generator

high-voltage power supplypower

DEVMO DC 3V-6V to 400kV Boost Step-up High-Voltage Generator Module

$10.994.4(508)

Prefer low-current educational modules over mains-powered high-voltage supplies. Review requirements and safety guidance before buying.

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

batterypower

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

$12.694.7(242K)

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

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

soldering ironfabrication

YIHUA 926 III 60W Digital Display Soldering Iron Station Kit

$39.994.4(6,900)

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

jumper wires / hookup wirewiring

120pcs Breadboard Jumper Wires, 20cm Dupont Cable Assorted Kit, Male to Female

$6.984.7(4,500)

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

inductor / coilpassive electronics

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

$13.994.8(182)

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

audio source / phoneaudio

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

$7.994.6(119K)

Use with an existing phone or audio player.

Valefod 6 Pack LM2596 DC to DC High Efficiency Voltage Regulator 3.2-35V to 1.25-30V Buck Converter DIY Power Supply Step-Down Module

voltage regulatorpower

6 Pack LM2596 DC-DC Step-Down Buck Converter Voltage Regulator Module

$9.994.5(1,100)

Anker USB A to USB C Cable, 2 Pack, 6ft

USB connector/cablewiring

Anker USB A to USB C Cable, 2 Pack, 6ft

$9.994.7(143K)

Cable recommendation; use connector/breakout boards where project wiring requires them.

Car Charger, Anker Quick Charge 3.0 39W Dual USB Car Charger Adapter, PowerDrive Speed 2 for Galaxy S10/S9/S8/S7/S6/Plus, Note 9, PowerIQ for iPhone 11/XS/Max/XR/X/8/7, iPad Pro, LG, Nexus, and More

car USB chargerpower

Car Charger, Anker Quick Charge 3.0 39W Dual USB Car Charger Adapter, PowerDrive Speed 2 for Galaxy S10/S9/S8/S7/S6/Plus, Note 9, PowerIQ for iPhone 11/XS/Max/XR/X/8/7, iPad Pro, LG, Nexus, and More

$25.994.8(19K)

CHANZON UL Wires 20PACK 9v Battery Dual Connector Clip UL Wires I Type Snap with Pigtail Housing Soft Leather Leads Wires for Adapter Replacement Terminal

9V battery snap connectorpower

CHANZON 20 Pack 9V Battery Snap Connector Leads

$7.994.6(872)

3M Scotch Vinyl Electrical Tape Super 88, 3/4 in x 44 ft, Black, 1 roll, Premium Grade, Rubber Resin Adhesive, PVC Backing, A

electrical tapefabrication

3M Scotch Super 33+ Vinyl Electrical Tape

$4.534.8(2,814)

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

Events, speaking, collaborations, and news.

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