PPT #1/2 Notes Flashcards
Silicon is a more stable semi-conductor than germanium. True or False?
True
The _______ the valence shell is to the nucleus, the more stable the semi-conductor is
closer
Which atom is physically larger, Germanium or Silicon?
Germanium
When many atoms combine through covalent bonding, they form a ______ ______ which is when the valence shell is full with no electron movement
silicon crystal
Classifications of matter are broken into 3 groups, what are they?
chemical
physical
electrical
The atom is the ________ particle and has the chemical characteristics of that element
smallest
Simple matter is composed of ______ basic earth elements
one
Complex matter is composed of ____ basic earth elements
two
A simple example of complex matter is?
H2O (two parts basic earth element)
The molecule is the smallest particle that retains the characteristics of that molecule. True or False?
True
Name three physical classifications of matter?
Solid
Liquid
Gas
Name three electrical classifications of matter
semi conductor
conductor
insulator
Name two semi-conductors
Silicon and Germanium
Name two insulators
mica, glass, wood
Name three conductors
copper, silver, aluminum, gold
A semi conductor is a solid substance that has the conductivity between that of an insulator and that of most metals, due to the addition of an impurity or because temp effects. true or false?
true
Atoms contain 4 major parts; name them?
Nucleus
Electrons
Protons
Neutrons
The heart of the atom is called?
Nucleus
The nucleus is comprised of?
Protons and Neutrons
The Nucleus is said to be __________ charged
positively
Orbiting the nucleus are negative charges called _________
electrons
The electrons are at different energy levels called _______
shells
Magnetic energy of the atom keeps __________ charged electrons in orbit by pulling them towards the _________ charged nucleus
negatively
positively
Kinetic energy also keeps electrons in orbit by stopping them from combining with the nucleus due to __________ _______
centrifugal force
What are the two reasons electrons stay in orbit around the nucleus?
Magnetic and Kinetic energy
Silicon and Germanium both contain __ valence electrons in their valence shell
4
Intrinsic material atom is considered to be in _________ state
neutral
In intrinsic neutral state atoms mean there are?
same number of protons and electrons
What is doping?
mixing impure (extrinsic) with pure (intrinsic) materials
Doping with impurities _________ the conductivity of the semi-conductor
increases
Conduction in a pure silicon crystal (achieved by covalent bonding) is only affected by heat or light energy. True or False?
True
Semi-conductors are doped to be either ___ type or ___ type
N-type or P-type
Semi conductors doped with impurities increase the ____________ of the semi-conductor
conductivity
Impurities with 5 valence electrons are called __________ and give the crystal an overall ________ charge or “__“-type
Pentavalent
negative
N-type
Impurities with 3 valence electrons are called ________ and give the crystal an overall __________. This will be “__”- type material
Trivalent
positive
P-type
N-type Silicon is doped with? (3)
Phosphorus
Antimony
Arsenic
P- type silicon is doped with? (3)
Aluminum, Gallium, Boron, Indium
Conventional current flow is ___ -_____
positive to negative
Electron flow is _________ to __________
negative to positive
For an electron to flow it must have a _______ to flow into
hole
The hole moves positive to negative, therefore the electron moves ?
negative to positive
P-type is the ________ and N-type is the _________
Anode
Cathode
Intrinsic layer in the middle of a diode is the ________ ______
depletion region
PN junctions are formed by fusing different _________ into the silicon crystal material
impurities
Name the two types of biasing
forward
reverse
Forward biasing is when the anode is positive with respect to the cathode. True or False?
True
What is Knee voltage?
cut in voltage
What is the knee voltages for silicon and germanium?
SI = 0.7v
GE= 0.3v
Depletion region disappears when knee voltage is applied and causes the ________ to drop and allows current to flow neg to pos
resistance
Reverse biasing is switching the direction of the current flow. True or False?
True
Reverse biasing changes the junction diode into a _________
resistor
Forward bias is _________ electron flow and Reverse biasing is __________ electron flow
conducting
resisting
No current will flow when the polarity on the diode is reversed. True or False?
True
Forward current means an increase in heat which will require the installation of a?
Heat sink
High voltage applied to a reverse diode will breakdown the diode and destroy it. This is known as ?
Avalanche current
Knee voltage?
Require voltage to put the diode into conduction
P.I.V?
peak inverse voltage
P.I.V is best described as?
amount of voltage the diode can safely handle in reverse
V.B.R?
Voltage breakdown reverse
V.B.R is best described as?
Point at which the diode will be destroyed?
Exceeding P.I.V = ______
V.B.R
Diode receives a higher voltage than your meter reads because it is receiving _____ vs RMS
PEAK
If infinity/O/L is seen on both sides of the diode it means it is?
open
If low ohms is read on both sides of the diode it means it is __________
shorted
What is the most popular diode we use daily?
LED
A transformer reduces voltage, isolates the circuit and prevents ground loops. True or False?
True
All diodes must be in ______ with the loads
series
The junction diode rectifier is used to (2)
- Rectify AC to DC
- As a blocking diode to prevent back emf
Name the three different types of rectifiers/regulators?
- Full-wave
- Half-wave
- Full-wave bridge rectifier
Name the two types of half-wave rectifiers
Positive half wave
Negative half wave
The positive half wave rectifier changes AC to DC by removing _____ _____ of the AC input signal. This creates a __________ ___ _________
one half
pulsating Dc voltage
How is a positive pulsating DC voltage created?
Using a half wave rectifier and removing one half of the AC input signal
The negative half wave has a diode that is _______ which will result in a pulsating dc voltage that is ________
negative
The only difference between the positive and negative rectification is?
the direction of the diode
Advantages of a half-wave rectifier? (2)
Simple construction and low cost
Disadvantages of a half-wave rectifier? (2)
High ripple factor (121%)
Low efficiency (45%)
Full-wave rectifier is also known as a?
centre tap transformer
Advantages of a full-wave/centre trap rectifier? (2)
Lower ripple factor (42%)
Higher efficiency (90%)
Disadvantages of a full-wave/centre tap rectifier? (1)
Higher cost of construction (centre tap transformer) and extra diode
Full-wave bridge rectifier advantages? (2)
no centre tap transformer
PIV rating of diode is less
Disadvantages of full-wave bridge rectifier?
Requires 4 diodes
Four things done to the power supply?
Transformer (protect and reduce)
Rectifier (AC to DC)
Filter (to smooth)
Voltage regulator (constant volts)