MadSci Network: Engineering
Query:

Re: How does electromagnetics affect everyday life and how is it used?

Date: Wed Feb 18 16:13:26 2004
Posted By: Yaxun Liu, Grad student, Electrical and Computer Engineering, University of Waterloo
Area of science: Engineering
ID: 1076507446.Eg
Message:

Electromagnetics is the knowlege and theory about electric and magnetic 
fields. When they are changing with time, electric and magnetic fields are 
always accompanying each other, therefore generally called electromagnetic 
fields, they can also be called electromagnetic wave or electromagnetic 
energy.

Electromagnetics have strong effect on our everyday life since without it 
many important technologies are impossible. Its main applications include
1) electric power generator
2) electric motor
3) radio and TV broadcasting
4) satellite TV
5) GPS
6) cell phones and mobile phones
7) wireless LAN
8) cable TV
9) microwave oven

Electric power generator converts motion energy to electromangetic energy 
and electric moter converts it back.

Microwave oven converts electromagnetic energy with low frequency to 
electromagnetic energy with very high frequency (several GHz), which is 
relatively easy to be absorbed by food and converted to heat.

All other applications use electromagnetic wave to transfer information. 
To do so you need an oscillator to generate high frequency electromagnetic 
wave, then use a modulator to put the information on the electromagnetic 
wave, and use an antenna to send out the electromagnetic wave. The 
receiver then use an antenna to collect the electromagnetic energy which 
carries your information from air. Because the power is weak, generally he 
needs an amplifier to make it stronger, then use a demodulator to pick up 
the information from the high frequency electromagnetic energy. This is 
the case for radio, TV, satellite TV, GPS, cell phones and wireless LAN. 
Cable TV does not need antennas, instead, it transmit the electromagnetic 
wave through cables, like tap water running through tubes.





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