-
Period: to
1.phase
-They are made of large empty tubes
-They use a lot of electricity
-They were used only as calcifiers -
Period: to
2. phase
-use smaller, cheaper and faster transmitters -
Period: to
3.phase
-IC is smaller but faster
-computers are faster and cheaper
-have fewer errors and less electricity -
Period: to
4.phase
-use micro processors
-They are portable and they are smaller and cheaper
-use less electricity -
Period: to
5.phase
-they are more advance
-they can think themselves