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About this Article
Written by: Shame Er Shah Kamal
Written on: November 4th, 2005
Tags: electrical engineering, lifestyle
Thumbnail by: Steve Woods
About the Author
Shame Er Shah Kamal was an Electrical Engineering major at the University of Southern California. In his spare time, he enjoys playing video games.
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Volume VIII Issue II > The Magnetic Stripe Technology
A credit card is ubiquitous in today's fast-paced society. The invention of credit cards has revolutionized the word, perhaps due to the fact that this object has made transactions faster, more secure, and trackable. What many forget is that the most important feature of a credit card is the black stripe often found at the back of the card. It is this glossy, dark, laminated plastic stripe that makes it possible to store data and make purchases with just a swipe. With electromagnetism, a piece of plastic turns into a tangible piece of information with immense power.

Introduction

Imagine yourself at the shopping mall, buying some new trendy clothes and you are about to pay the cashier. The total cost of your purchase is $200, but you realize that you do not have enough money in your wallet. Consequently, you slip out your credit card from your wallet and hand it to the cashier.
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She takes the card and swipes it through a card reader. After a few seconds, the young woman hands back your card with a receipt, a thank you, and a generous smile. In that particular moment, you might wonder, "What just happened?"
The answer lies on the back of your card. The black stripe, also known as the magnetic stripe, is what makes this possible.

History

Magnetism has added much to recent technological advancements, from medical to commercial advanced. While the principle of magnetism has been with us since the dawn of time, humans had yet to utilize its full potential until 1821. A Danish scientist named Hans Christian Oersted encountered a strange phenomenon. Oersted noticed that when a compass is in close proximity to a wire that has electric current applied to it, an invisible force causes the needle of the compass to move. Later studies done by renowned scientists like Andre-Marie Ampere and Michael Faraday have helped to explain this strange phenomenon: magnetism [1].
Since then, scientists have made numerous groundbreaking discoveries that have led to the creation of a variety of new technologies. The first useful development of the technology was set forth by the magnetic wire recorder for the telegraphone, invented by Vlademar Poulsen in 1898 [2]. The principle that governs the telegraphone is relatively simple: as a magnet, driven by electric current (representing streams of data that were transformed by analog-to-digital converter), passes along a wire, a primitive type of magnetic material, the wire remains magnetized, thus locking the data on the material. Another magnetic-recorded appliance that capitalizes on the principles laid by the telegraphone includes magnetic tape.