Conductors , Insulators And Semi Conductors Flashcards
Describe a insulator
Large gap between a empty conduction band and full valence band. No charges can move.
Describe a conductor
Full-electron-Conduction band and valence band overlap. Electrons are free too move
What does RMS stand for
Root mean squared
What does RMS voltage/current mean
When the current or voltage is equal
What does the Forward bias do to the electric field?
Reduces it
What does reverse bias do to the electric field?
Increases it
Describe a semi conductor
Small band gap distance
0K
No electrons in conduction band
Acts as insulator
At room temperature what can a semi conductor do
It has sufficient energy to move some electrons from the valence band to conduction band
Small band gap
Describe what happens when a semi conductor is at a high temperature
More energy
More electrons can flow in the conduction band
In a semi conductor, as the temperature increases
The conduction increases
What makes a solid conductor, conduct?
Needs free electrons and accessible empty states
Partially filled bands
How can you dope up a semi?
Grow the silicon
Add few atoms of different type as they donate electrons to the conduction band
Extra atoms- donors- e.g, phosphorus
Describe a n-type band
Extra electrons occupy levels close to conduction band
Easily excited to conduction band
More impurities
More free electrons
Greater conductivity
Describe a p-type band
Absences of electrons just above valence bands
Electrons can easily move to spaces
Spaces led in valence band
Allows conduction
As crystal p-n junction is being formed you…
Dope one half of crystal with p-type impurity
Dope other half with n-type impurity
Current flows one way from the diode.
