Module 3 Flashcards
What is a semiconductor
A solid material whose conductivity lies somewhere between an insulator and conductor
How to increase conductivity of a semiconductor?
Doping - Introduction of other atoms to add charge carriers.
Types of semiconductors
N - type Excess of Valence electrons(Silicon lattice containing phosphorus)
P - type: Deficit of valence electrons(Silicon lattice containing boron)
How do these work together
As p-type region is positively charged relative to n-type, electrons are attracted across boundary. On n-type side as e cross junction, area near it become positively charged.
Depletion region
When potential difference opposite rest of junction forms, thus blocking any further flow of charge.(Forward bias)
What happens when potential difference in the same direction?(Reverse bias)
Depletion region widens
DC-AC rectification
Diode converts AC to DC - circuit with diode is called a rectifier
What happens when current flows through a PN junction
Voltage drop(Always)
Bipolar Junction Transistor
When 2 PN junctions are connected, e is now attracted to P-type region as junction is now forward biased. More free electrons (due to narrowness). Thus, some electrons flow through closed circuit.
What happens when depletion region decreases
Current flows across whole junction
Parts of NPN transistor
P - Base
N1 - Emitter
N2 - Collector
Bipolar junction
No matter what direction the voltage is inputted, one side will always be reversed biased junction
