Monday, December 10, 2007
Monday, December 10, 2007
Posting for the first time.
The World's Smallest Radio
A tiny radio made out of a single nanotube could find use in biological and environmental sensors.Some researchers have fashioned the world's tiniest radio out of a carbon nanotube.The nanotube combines the roles of all the main electrical components in the radio.It can tune in to a radio signal and play the audio through an external speaker. It could be used in biological and environmental sensors.The nanotube radio works differently than a conventional radio does.Conventional radios have four main functional parts.Radio waves falling on a radio antenna create electric currents at different frequencies.When someone selects a radio station, the tuner filters out all but one of the frequencies.Transistors amplify the signal, while a demodulator, typically a rectifier or a diode, separates the data--the music or other audio--that has been encoded on a "carrier" electromagnetic wave.The nanotube is grown sticking out from a tungsten surface, which acts as a negative electrode. The tip of the carbon nanotube is also negatively charged.A vacuum separates the nanotube from a positive copper electrode. The researchers use an external battery to apply a voltage between the two electrodes. Electrons jump out from the negative nanotube tip to the positive electrode, creating what is called a field emission current.
MY DNT BLOG
3:41 AM