Basic Electronics Flashcards
The atomic theory is largely credited to who?
John Dalton
Diameter of typical Nucleus
1x10^-14
Thomspon’s model of the atom
PLum pudding, (he discovered electron)
Rutherford’s discovery of subatomic particle
Proton
Chadwick’s discovery of subatomic particle
Neutron
What consists of proton?
2 up quark
1 down quark
Composition of neutron?
2 down quark
1 up quark
formula of maximum number of electrons in a given shell, n
n=2n^2
What letter does the first electron shell starts?
K
What is Pauli’s Exclusion Principle
no two electrons can have the same set of four quantum numbers
Equivalent of 1 eV in Joules
1.602x10^-19 J
Group IV elemental semiconductors
Diamond (C)
Silicon(Si)
Germanium(Ge)
The energy Required to move an electron from the valence band into the conduction band
energy gap (Eg)
It is the bonding resulting from the attractive forces of oppositely charged ions
Ionic band
It is the product of the attractive forces of group of positive ions and electrons, where the electrons are generally free to move about its ions
Metallic bond
It is when atoms of materials share electrons with another atoms
Covalent bond
At absolute zero temperature, how many free electrons are found in a semiconductor?
Zero, because they are locked in their valence bond
It refers to pure Semiconfuctors and free from impurities
Intrinsic materials
Semiconductors that are doped with impurities
Extrinsic Materials
it is the process of adding impurities
doping
Common pentavalent(N-Type) materials
Antimony(Sb) Arsenic(As) Phosphorus(P)
Common trivalent(P- Type) elements
Boron(B) Gallium (Ga) and Indium (I)
The difference on the effect of lightly and heavily doping a semiconductor
lightly doped - few impurities, higher resistance
heavily doped - more impurities, lower resistance
What is the depletion region?
no electrons or holes
It is the simplest diode
point contact germanium diode
It is where anode is more positive than the anode nd where the diode allow current to flow
Forward bias
It is the maximum voltage that can be applied that can be handled by the junction diode
Breakdown voltage
*note that silicon has higher breakdown voltage than germanium
Diode forward current equation
Id = Is*(e^(kVd/Tk) - 1)
Id = diode current Is = reverse saturation current/Leakage current Vd = forward diode voltage Tk = room temp, in Kelvin k = 11,600/n n = 1 for Ge , 2 for Si (1 by default)
Formula for Effect of temperature on reverse saturation current
I(snew) = I(s)·e^k(T1 - T0)
I(snew) =reverse saturation current at new temperature I(s) =reverse saturation current at room k = 0.07 T1 = new temperature T0 = room temperature
Formula for Effect of temperature on threshold voltage
Vth1 = Vth + k*(T1 - T0)
Vth1 = threshold voltage at new temperature Vth = threshold voltage at room temperature ( 0.3 V for Ge and 0.7 V for Si) k = -2.5 mV/C for Ge = -2.0 mV/C for Si T1 = new temperature T0 = room temperature
Three Diode Equivalent Models
Ideal Diode Model
Simplified Diode Model
Piecewise Linear Diode Model
A diode model with no threshold voltage required and has no resistance when forward biased
Ideal Diode Model
A diode model when forward biased has threshold voltage and has no resistance
Simplified Diode Model
A diode model when forward biased has threshold voltage and resistance
Piecewise Linear Diode Model
Threshold Voltage for Silicon
0.7 V
Threshold Voltage for Germanium
0.3 V
The forward resistance of the diode under DC circuit analysis
Static Resistance
Formula for Static Resistance
Rd = DC voltage across the diode / Diode's current Rd = Vd / Id
The forward resistance of the diode under AC circuit Analysis
Dynamic Resistance
Formula for Dynamic Resistance
rd = small change of voltage / small change of diode's current rd = dVd / dId rd = 26 mV / Id
The forward resistance of the diode under AC circuit analysis
Average AC Resistance
Formula for Average AC Resistance
r(ave) = Change in voltage across the diode / Change in diode's current r(ave) = Δ Vd / Δ Id
Capacitance prominent when diode is Forward-biased:
The diffusion / storage capacitance
Capacitance prominent when diode is Reverse-biased:
The transition / depletion-region capacitance
At lower frequency the diode(due to capacitance) acts like a ___________
Open circuit
At high frequency the diode(due to capacitance) acts like a ___________
Short Circuit
The magnitude of current that the diode can handle without burning when forward biased
Forward Current
This is the required voltage in order to produce forward current
Forward Voltage
The magnitude of current that will leak when the diode is reverse-biased
Reverse Saturation current
Other term for Reverse Saturation current
Leakage Current
This is the maximum reverse voltage that can be applied before current surge and enters the Zener region
Reverse Breakdown Voltage
Peak Reverse Voltage
Peak Inverse Voltage
This is the time taken by the diode to operate from forward conduction to reverse bias condition
Reverse Recovery Time
The maximum power the diode can handle without burning
Maximum Power Dissipation
The factor that tells the reduction of power handling capability of the diode due to the increase of ambient temperature from room temperature
Linear Power Derating Factor
The maximum temperature the diode can operate before burning its junction
Maximum Junction Temperature
Formula for Reverse Recovery Time
T(rr) = t(s) + t(t)
T(rr) = the time elapsed from forward to reverse bias t(s) = the transition time t(t) = the storage time
Analogous to the junction diode except that the doping is controlled precisely so that it will have a well defined and smaller breakdown voltage
Zener Diode
The Zener effect was discovered by
Dr. Clarence Melvin Zener
Formula for Temperature Coefficient (measures ΔVz ad temperature changes)
Tc = ΔVz / Vz (T1 - T0) x 100%
ΔVz = Resulting Change in Zener Potential Vz = The Zener Diode Breakdown Voltage T1 = new temperature T0 = room temperature
A Variable Capacitor, Commonly used in parametric amplifiers, parametric oscillators and voltage-controlled oscillators as part of phase-locked loops and frequency synthesizers
Varactors
Varactors are usually operated in what bias
Reverse-Biased
It is the sum of the junction and case capacitances
Total diode capacitance
It is the resistance in series with the junction of the diode
Series resistance
Formula for Quality Factor of a varactor
Q = 0.159 / (f·R(s)·C(t))
f = frequency in Hertz R(s) = series resistance in ohms C(t) = total capacitance in farad
It is the frequency where the quality factor of the varactor is 1
Cutoff frequency
It is the ratio of capacitance variation at a reverse voltage of -4 or -6 to the capacitance at approximately 80 percent of the breakdown voltage
Total Capacitance Ratio
It is defined as the performance of a varactor used as a frequency multiplier
Conversion efficiency(varactor)
Formula for Conversion efficiency(of a varactor)
η = Po / Pi x 100%
Relation of temperature to capacitance
directly proportional
Diodes usually made of doped silicon or germanium
Generic Diode
Type of diode that is made to conduct backwards
Zener Diode
Conduct in the reverse direction when the reverse bias voltage exceeds the breakdown voltage
Avalanche diode
Occurs when the reverse electric field across the pn junction causes a wave of ionization
Avalanche effect
Reverse Breakdown of avalanche diode
6.2 V
Are avalanche diodes designed specifically to protect other semiconductor devices from electrostatic discharges
Transient voltage suppression diode (TVS)
Type of diode that subject to optical charge carrier generation and therefore most are packaged om light blocking material.
Photodiodes
Type of diode that formed in a direct band-gap semiconductor, such as gallium arsenide, carriers that cross the junction emit photons when they recombine with majority carrier on the other side
Light Emitting Diode (LED)
Forward potential of Red LED and Violet LED
1.2 V and 2.4 V
What is the first LEDs created
Red and Yellow
An LED-like structure is contained in a resonant cavity formed by polishing the parallel end faces
Laser Diode
A Diode that have a lower forward voltage drop than a normal PN junction, because they are constructed from a metal to semiconductor contact.
Schottky Diode
is a semiconductor junction diode having the ability to generate extremely short pulses (Low Reverse Recovery Time).
step recovery/snap-off diode
a two-terminal semiconductor diode using tunneling electrons to perform high-speed switching operations
Esaki or tunnel diode
Similar to tunnel diode that exhibit a region of negative differential resistance and is used in Microwave Frequency Oscillation
Gunn diodes
A block of n-type semiconductor is built, and a conducting sharp-point contact made with some group-3 metal is placed in contact with the semiconductor.
Point Contact Diode
They are used as voltage-controlled capacitors
Varicap
A diode with similar to JFET which allow a current through them to rise to a certain value
Current-limiting field-effect diodes
Some diode applications
Radio Demodulation Power Conversion Over-voltage Protection Logic Gates Ionizing Radiation Detectors Temperature measuring Charge coupled devices
It is a three terminal current controlled solid state device which is capable of amplifying signals
Transistor
Who invented the transistor?
John Dalton and Walter Brattain
Bell Laboratories
1947
What are the first type of transistor?
Point-Contact Type
The theorist who was leading the research about point-contact type transistor
William Shockley
The main conduction channel employs both electrons and holes to carry the main electric current.
Bipolar Junction Transistor (BJT)
Three parts of the transistors
Emitter, Base and Collector
Two basic modes of transistor
Switch and Amplifier
When the Base-Emitter is Forward and Base-Collector is Reverse, The operating mode is
Active or Amplifier
When the Base-Emitter is Forward and Base-Collector is Forward, The operating mode is
Saturation ( On Mode )
When the Base-Emitter is Reverse and Base-Collector is Reverse, The operating mode is
Cut-off ( Off Mode )
Current Relationships of TBJT
IE = IB + IC + ICBO
ICBO ≈ 0 (neglible)
It is the common base amplification factor
α (alpha)
Formula for α (alpha)
α = IC / IE
It is the common emitter forward current amplification factor
β (beta)
Formula for β ( beta)
β = IC / IB
It is the common collector forward current amplification factor
γ = IE / IC
Parameter Relationship for α, β and γ
α = β / β + 1 β = α / α - 1 γ = 1 + β
It is used for impedance matching application especially for low to high impedance conversion
Common Base Configuration
It is most used configuration for amplifier application
Common Emitter Configuration
It is also used for impedance matching application especially for high to low impedance conversion
Common Collector Configuration
A process of applying a DC voltage to a transistor to achieve the preferred region of operation or for what application is the transistor intended
Biasing
Type of biasing which has the greatest power gain but the most unstable type of biasing.
Fixed Bias
Type of biasing which is considered the most stable of all the biasing configurations but requires more resistors than any other biasing
Voltage divider bias configuration
Type of biasing which is more stable than fixed-bias but with a smaller power gain
Emitter-stabilized bias configuration
Type of biasing which has the advantage of requiring fewer resistors compared to voltage divider bias without reducing the stability
Voltage feedback bias configuration
Two main criteria considered in choosing which bias configuration is to be used
Power gain
Stability
When temperature increases, the β ______________
When temperature increases, the Vbe ____________
When temperature increases, the Ico __________
increases
increases
increases
Formula for stability factors
S(Ico) = ∆Ic / ∆Io S(Vbe) = ∆Ic / ∆Vbe S(β) = ∆Ic / ∆β
Formula for Total Change of Collector Current
∆Ic = S(Ico) ∆Ico + S(Vbe) ∆Vbe + S(β)∆β
The most commonly used model in small signal analysis of transistors
Hybrid Parameter Model
Equations for H-Parameter
Vi = hi⋅Ii + hr⋅Vo Io = hf⋅Ii + ho⋅Vo
Formula of a re model
re = 26 mV / IE
Comparison between H-parameter and Re model
For input impedance or resistance re ≈ h(ib) βre≈h(ie)≈h(ic) For amplication factor α≈h(fb) β≈h(fe)≈h(fc)
Parameter for Common Base
Input impedance - Low Output Impedance - High Current Gain - Low ≈ 1 Voltage Gain - High Power Gain - Moderate Phase shift - None
Parameter for Common Emitter
Input impedance - Moderate Output Impedance - Moderate Current Gain - Moderate Voltage Gain - Moderate Power Gain - High Phase shift - 180°
Parameter for Common Collector
Input impedance - High Output Impedance - Low Current Gain - High Voltage Gain - Low ≈ 1 Power Gain - Low Phase shift - None
Transistor model know as the transistor physical representation
T-equivalent circuit
Transistor model used in DC analysis
Ebers-Moll model
Transistor model used in small signal analysis
Hybrid model
Transistor model used in high frequency analysis
Hybrid-pi model or Giacolleto model
Transistor model used small signal and large signal analysis
Dynamic or re model
Is a transistor that uses an electric field to control the electrical behavior of the device.
Field-Effect Transistor
Different types of field-effect transistor
JFET ( Junction Field-Effect Transistor )
MOSFET ( Metal-Oxide-Semiconductor Field-Effect Transistor )
MESFET ( Metal-Semiconductor Field-Effect Transistor )
HEMT ( High Electron Mobility Transistor )
Is a unipolar device that is either only electron or hole is the charged carrier but not both
JFET ( Junction Field-Effect Transistor )
Is an electronic amplifying vacuum tube (or valve in British English) consisting of three electrodes inside an evacuated glass envelope
Triode
Formula for Drain current for FET
i(d) = I(DSS) ( 1 - (VGS / VP))^2 i(d) = Drain current I(DSS) = Drain to Source Current Saturate VGS = Gate to Source Voltage VP = Pinch Off Voltage
It is constructed by placing an insulting layer between the gate and the channel allows for a wider range of control voltages and further decreases the gate current
MOSFET ( Metal-Oxide-Semiconductor Field-Effect Transistor )
Type of MOSFET which has a channel in resting state that gets snakker as a reverse bias is applied, this device conducts current with no bias applied
D-MOSFET ( Depletion Metal-Oxide-Semiconductor Field-Effect Transistor )
Type of MOSFET which is built without a channel and does not conduct current when Vgs = 0
E-MOSFET ( Enhancement Metal-Oxide-Semiconductor Field-Effect Transistor )
Type of FET which quite similar to a JFET in construction and terminology. The difference is that Schottky junction is used.
MESFET ( Metal-Semiconductor Field-Effect Transistor )
It is a FET with a junction between two materials with different band gaps as the channel instead of an n-doped region
HEMT ( High Electron Mobility Transistor )
Conductors ideally have _____ valence electrons
1
Valence electron count of a conductor
Less than four
Group in Periodic table attributed with properties that make them conductors
Group 1B
Cu, Ag, Au
Insulators ideally have _____ valence electrons
8
Valence electron count of an insulator
More than four
A Semiconductor has _______ valence electrons
4
Semiconductors act like _________ at 0°K
Insulator
Insulators have energy gaps above
5 eV
With a conductor, its valence band _______ the conduction band
Overlaps
∴ Eg Conductor = 0 eV
The distance of the electron from the nucleus is ________ proportional to the energy gap required for electron to move to conduction band
Inversely Proportional
∴ As atomic number decreases, energy gap increases
Energy Gap of Silicon
1.1 eV
Energy Gap of Germanium
0.67 eV
Energy Gap of Gallium Arsenide
1.43
Energy Gap of Gallium Phosphide
2.26
At 0°K, there are ______ free electrons in a semiconductor
zero
The number of free electrons in 1 cm³ of Silicon
1.5 x 10^10 electrons
The number of free electrons in 1 cm³ of Germanium
2.5 x 10^15 electrons
At room temperature, Silicon is _________
Insulative
At room temperature, The Thermal energy will only produce ______ free electrons in a material
few
A Doped Semiconductor that are doped with Trivalent Impurities
P-Type Semiconductor
A Doped Semiconductor that are doped with Pentavalent Impurities
N-Type Semiconductor
Another term for Trivalent atoms
Acceptor atoms
3 Valence electrons; to become four Valence semiconductor, atom must ACCEPT an electron
Another term for Pentavalent atoms
Donor atoms
5 Valence electrons; to become four Valence semiconductor, atom must DONATE an electron
P-Type Semiconductors have _______ as Majority Carriers, and _________ as Minority Carrier
Holes as Majority Carriers (P-Type, POSITIVE)
Electrons as Minority Carriers
N-Type Semiconductors have _______ as Majority Carriers, and _________ as Minority Carrier
Electrons as Majority Carriers (N-Type, NEGATIVE)
Holes as Minority Carriers
Net Charge INSIDE The depletion region of a PN Junction is _____
Zero
In Forward Bias Condition, The Depletion Region ______
Narrows
In Reverse Bias Condition, The Depletion Region ______
Widens
Alternative Forward Current (Id) Equation
Id = Is( [e^(Vd / (nVt)] - 1)
Vt - Thermal Voltage (26mV @ 300°K)
Vd - Forward Diode Current
Is - Reverse Saturation/Leakage Current
n - 1 by default
Formula for Thermal Voltage (Vt)
Vt = k*T / qe
k - Boltzmann’s Constant
T - Temperature(in °K)
qe - Electron Charge (1.6 x 10^-19 C)
The Storage/Diffusion Capacitance is the _______ of the diode
Maximum
C =Ea/d, DR acts as dielectric, and since DR is thin at forward bias, Capacitance increases
The Transition/Depletion-Region Capacitance is the _________ of the diode
Minimum
C =Ea/d, DR acts as dielectric, and since DR is thick at reverse bias, Capacitance decreases
Why does a PN Junction diode have capacitance in the first place?
DR acts like a Dielectric(any non-conductor) between two plates (P-Type and N-Type Material act like plates)
Reverse Recovery Time ranges from _____ to ____
few nanoseconds to few hundred picoseconds
