Tip - Build a Cell Phone Charger in Five Minutes While Inside Radio Shack

YouTube user Spiritplumber demonstrates how he built a cell phone charger using four parts from Radio Shack on the store counter immediately after his purchase. The parts cost around ten bucks, and while that's three times cheaper than buying the actual cable at Radio Shack, but how did he know he wouldn't blow out his phone?
Tags: Electronics, Cell Phones, Batteries, Battery Chargers, Lifehacker