With the iPhone initially and then iPod touch, the touch screen systems are becoming more and more common. The apple’s new innovation Mac Air’s mouse pad is its self a multi touch screen. But how does this all stuff work. Touch screen is not a new phenomina introduced by Apple rather, Apple computers just specialized and refined the technology to greater level and placed it direcly in the consumers hands, though as far as i remeber Microsoft was yet another company who had build the touch screen with there product Surface but the mistake they made they never made it for regular consumers. “Greed Kills” rather build it for corporations and once after launch we never heard about it as far as i see the Product build by Microsoft was more complex then iPhone but still it wasn’t for average joe.

Ever wondered how the the touch screen works, its quite interesting how the simple and unique the technology is.

Standard Touch Screen Technology
The resistive layer consist of a normal glass panel covered with a conductive and a resistive metallic layer. These two layers are help apart by spacers, and a scratch-resistant layer is placed on top of it. An electrical current runs through the two layers. When a user touches the screen the two layers make contact in that exact spot and his touch cordinates are noted down and delivered to the operating system which makes its decisions. This is the most simple form of touch screen.

The Apple Touch Screen Technology
The second one which is used as a primary base by iPhone and Apple computers is the Capacitive System. This system has a layer that stores electrical charge and is placed on the glass panel. When a user touches with his or her finger, some charge is transferred to the user and the charge on the capacitive layer decreases. The decrease is measured in circuites located at each corner and the operating system measures from difference in charge at each corner.

But Apple improved the Capacitive System, they created a grid of capacitive layer which has a circuitry that can sense changes at each point along the grid. Simply every poin on the grid generates its own signal when touched and relays that singnal to the iPhon capacitors which in response provides such functionality. As all the grids have there own signal thats why Apple touch screen is a multi touch screen.

But one this is quite clear if you use your finger to touch the screen it would work but if you are wearing a glove it wont as not current will be transfered to your body and the signal wont change. So yes iPhone, iPod touch do transfer electric charge in your body when you use it. But its not fatal so iPhone or iPod can’t kill.

Ref: HowStuffWorks