Semiconductors And Diodes Flashcards
(28 cards)
What is a diode?
A 2 terminal semiconductor device allows current to flow in only One Direction
What direction does a diode allow current to flow in
The direction of the arrow in the symbol
What do diodes do to current In the opposite direction of the symbol
Blocks the current acting like an open circuit
It diode is on if and only if
The current established by the applied source is such that the arrow in the diet matches that of the current and VD is more than the potential of the diode
What are the steps to solving in diode circuits?
Analyze the circuits to see if the diode is on. find VD VRS Then find the current using the VRS
What is the value of current and voltage of the diode if the diode is not on ?
The VD is what ever the Vs is but current is zero
What is the value of current and voltage of the diode if the diode is not on ?
The VD is what ever the Vs is but current is zero
What is a semiconductor?
A material with electric conductivity between an insulator and conductor
What is intrinsic semiconductors?
Pure elements such as silicone and gum that possess 4 valence electrons
What are extrinsic semiconductors?
Pure semiconductors that have been doped
What is doping?
The process of adding a controlled amount of impurities (another element) to a semiconductor to enhance it’s conductive properties
What are the types of extrinsic semiconductors?
N type and P type
What are N type semiconductors?
Semiconductors that have been doped with pentavalent impurities
What are P type semi conductors
Semiconductors that have been duped with trivalent impurities
Give an example of impurities used in N type semi conductors
Phosphorus and arsenic
Give an example of impurities used in P type semiconductors
 aluminum and boron
What is a PN junction?
A semiconductor that has been doped in such a way that one region is ᴾ type and the other is N type
What happens when you semiconductor is under no bias
Initially when the materials are joined the majority carriers of each semiconductor within the depression area crosses the barrier. this causes no net charge preventing further conduction. And there is not enough kinetic energy to overcome come the depletion area
What happens to a semiconductor PN junction in forward bias?
The forward-voltage exceeds the the barrier potential and overcomes the depletion region causing the depletion region to narrow and for current to flow.
What happens to EPN junction in reverse bias
The external voltage applied reinforces the electric field of the depletion region and the region widens restricting current flow
What is rectification?
Converting AC to a pulsating DC current through the use of diodes.
What is the construction for a bridge network rectifier
Four diodes are set up in such a way that D1 and D2 are successive
While D3 and D4 are successive
D1 and D4 are on while D2 and D3 are of and vice Verda
