SLIDEDOC 

TEMPLATE

February 24, 2014

Prepared by:

Your Name Here

Template created by Duarte

Technology

The telephone invention could turn sound waves into electrical signals. The first telephones had a microphone that used carbon powder. The carbon powder had a electrical field running though it and the pressure from sound would compress the carbon and increase electrical conductivity. The carbon granules had to compress and decompress several thousand times a second to reproduce a human vice.