Electronics Flashcards
What does Electronics deal with?
Electronic circuits that operate by controlling the flow of electrons or other electrically charged particles.
What is an intrinsic semiconductor?
A perfect, pure semiconductor crystal containing no impurities.
What is band gap energy E?
Minimum amount of energy required to excite an electron from valence band to conduction band.
What do holes do?
Move in opposite direction to that of electrons and participate in conduction of electricity. Electrons move to CB and Holes to VB.
What is doping?
An addition of impurity(dopant) into an intrinsic semiconductor.
What is an extrinsic semiconductor?
A semiconductor doped with impurity atoms.
Do dopants cause any distortion in the original crystal structure?
No, they are substitutional impurities.
What are donor atoms?
The impurity atoms which contribute electrons to the CB without producing holes in the VB.
What are Majority and Minority carriers in N-type SM?
Electrons in majority carriers while holes are minority carriers since they are small in number.
What does N indicates in N-type extrinsic semiconductor?
Negative sign of the majority carriers.
When is N-type semiconductor produced?
Pure semiconductor doped with pentavalent impurity (phosphorous or arsenic.)
When is P-type semiconductor produced?
Pure semiconductor doped with trivalent impurity (boron or aluminum.)
What are acceptor atoms?
Impurity atoms which accept electrons from the VB and produce holes without an electron in the CB.
What are majority and minority carriers in P-type SM?
Holes are majority carriers while Electrons are minority carriers.
What does P indicate in P-type extrinsic semiconductor?
Positive sign of the majority carriers.
How is a junction diode formed?
By placing a P type crystal in contact with N type crystal and subjected to high pressure so they become one.
How is electron field directed from N to P type region created?
Electrons from N type fill vacancies in P region, forming negative and positive ions.
What does the field do?
Stops diffusion of electrons and holes and maintains the separation of charge carriers. This region is called depletion region free of mobile charges.
What is forward bias and current?
When majority charge carriers cross the junction and current flows at point, knee voltage- this is called forward bias and the current forward current.
What is reverse bias and current?
If P region is made negative, no majority charge carriers cross the junction instead current flows due to the minority charge carriers. This is reverse bias and the current reverse current.
What is rectification and rectifier?
The conversion of AC into DC is called the rectification and device used for it is rectifier.
