Soild State Review

Solid State Devices: The DiodePresented by: Jupelm Alesna EcE #46806

SemiconductorSolid State Devices/Semiconductor Doping The PN Junction Types of Diode Diode Rectification

Solid State DevicesWhat is a Solid State Device?Controls and engineering systems in the old days are implemented by mechanical means such as reeds and relays. After the invention of vacuum tubes, controls have been more easier. Immediately following the vacuum tube era was the invention of solid state devices, which were generally made by semiconductor. First was the diode, then followed by the transistor.

Solid State Devices SemiconductorSemiconductor FundamentalsMatter takes its characteristic based on the elements that composes it. Elements can be classified based on their electrical characteristics:Conductor Insulator Semiconductor

Semiconductor Fundamentals MatterAn ELEMENT is a substance that cannot be reduced to a simpler form by chemical means. Iron, gold, silver, copper, and oxygen are all good examples of elements. A COMPOUND is a chemical combination of two or more elements. Water, table salt, ethyl alcohol, and ammonia are all examples of compounds. A MOLECULE is the smallest part of a compound that has all the characteristics of the compound. Each molecule contains some of the atoms of each of the elements forming the compound. The ATOM is the smallest particle into which an element can be broken down and still retain all its original properties. An atom is made up of electrons, protons, and neutrons. The number and arrangement of these particles determine the kind of element.

Semiconductor FundamentalsConductor, Insulator, and Semiconductor These elements have unique electrical characteristics because of:Valence Electrons Band-Gap/Energy Level Different Resistivity

Semiconductor Fundamentals Valence ElectronsThe electron theory states that all matter is composed of atoms and the atoms are composed of smaller particles called protons, electrons, and neutrons. The electrons orbit the nucleus which contains the protons and neutrons. It is the valence electrons that we are most concerned with in electricity. These are the electrons which are easiest to break loose from their parent atom. Normally, conductors have three or less valence electrons; insulators have five or more valence electrons; and semiconductors usually have four valence electrons.

Semiconductor Fundamentals Band-GapENERGY BANDS are groups of energy levels that result from the close proximity of atoms in a solid. The three most important energy bands are the CONDUCTION BAND, FORBIDDEN BAND, and VALENCE BAND.

QuestionsWhich of the following rules govern the distribution of electrons in each shell in an atom?1. Theory of uncertainty 2. Quantum distribution 3. Pauli exclusion principle 4. Gaussian Distribution

Questions Quantum Numbers

QuestionsWhich of the following terms is used for the decrease in resistance as the temperature of the semiconductor increases?1. Positive temperature coefficient 2. Negative temperature coefficient 3. Faraday temperature coefficient 4. Zero temperature coefficient

Semiconductor Fundamentals Resistivity

Semiconductor Fundamentals Common SemiconductorsGermaniumAtomic Number: 32 Has Small Band-gap Used in small-signal application

SiliconAtomic Number: 14 Second most abundant element in the earths crust (25.7% by mass). Better noise floor compare to Ge.


Semiconductor Fundamentals DopingDoping refers to the process of intentionally introducing impurities into an extremely pure (also referred to as intrinsic) semiconductor in order to change its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductor is referred to as extrinsic. A semiconductor which is doped to such high levels that it acts more like a conductor than a semiconductor is called degenerate.

Semiconductor Fundamentals DopingThe number of dopant atoms needed to create a difference in the ability of a semiconductor to conduct is very small. Where a comparatively small number of dopant atoms are added (of the order of 1 every 100,000,000 atoms) then the doping is said to be low, or light. Where many more are added (of the order of 1 in 10,000) then the doping is referred to as heavy, or high.

Semiconductor Fundamentals DopingFor the group IV semiconductors such as silicon, germanium, and silicon carbide, the most common dopants are group III or group V elements. Group III dopants: Boron, Indium, Gallium, and Aluminum Group V dopants: Phosphorus, Arsenic, Antimony, and Bismuth Quick mnemonic for this is BIG-PAA.

Semiconductor Fundamentals DopingBoron is the p-type dopant of choice for silicon integrated circuit production, since it diffuses at a rate which makes junction depths easily controllable. Phosphorus is typically used for bulk doping of silicon wafers, while arsenic is used to diffuse junctions, since it diffuses more slowly than phosphorus and is thus more controllable.

Semiconductor Fundamentals DopingGroup III dopants creates broken bonds or holes in the lattice. This results in P-Type material. Thus, group III dopants are said to be electron acceptor. Group V dopants provide extra valence electrons are added which become unbonded from individual atoms and allow the compound to be electrically conductive, n-type material. Thus, group III dopants are said to be electron donor.

Semiconductor Fundamentals Doping: IMPORTANT NOTE

Semiconductor Fundamentals Doping: Dopants SummaryDOPANT Also called as Electron Acceptor Elements Valence Electron 3 Material Formed P-type

Boron Group

Boron, Indium, Gallium, Aluminum Phosphorus, Antimony, Arsenic, Bismuth

Pnictrogen Groups

Electron Donor

5

N-type

QuestionsWhich of the following electronic devices operates by virtue of the movement of electrons within a solid piece of semiconductor material?1. Transistor 2. Junction diode 3. Solid-state device 4. Each of the above

QuestionsWhich of the following electronic devices is a minute piece of semiconductor material that can produce complete electronic circuit functions?1. Zener diode 2. Light-emitting diode 3. Integrated circuit 4. Field effect transistor

QuestionsOne of the most sensitive elements of semiconductor materials is galena. Galena is a crystalline form of what material?1. Krypton 2. Bismuth 3. Strontium 4. Lead sulfide

QuestionsWhich of the following advantages, if any, does a conventional electron tube have over a semiconductor device?1. It is more efficient 2. It has a longer life 3. It is more economical 4. None of the above

QuestionsWhen compared to an electron tube, the semiconductor device has which of the following limitations?1. The semiconductor is more sensitive to temperature 2. The semiconductor is used only in radar equipment 3. The semiconductor is difficult to adapt to commercial products 4. Each of the above

QuestionsWhich of the following terms is defined as the process by which an atom gains or loses electrons?1. Quanta 2. Ionization 3. Loss of energy 4. Remaining energy

QuestionsElectrons are NEVER found in which of the following bands?1. Energy band 2. Valence band 3. Forbidden band 4. Conduction band

QuestionsWhat determines whether a substance is an insulator, semi-conductor, or conductor?1. The separation between the valence and forbidden bands 2. The separation between the conduction and valence bands 3. The separation between the conduction and forbidden bands 4. The separation between the forbidden band and the energy gap

QuestionsWhich of the following terms applies to the process that holds the atom together in a crystal?1. Suhl effect 2. Superposition 3. Boundary defect 4. Covalent bonding

QuestionsWhat name is given to the outermost shell of an atom?1. First shell 2. M shell 3. Valence shell 4. Subshell

Semiconductor Conduction ProcessThe CONDUCTION PROCESS in a SEMICONDUCTOR is accomplished by two different types of current flow: HOLE FLOW and ELECTRON FLOW. Hole flow is very similar to electron flow except that holes (positive charges) move toward a negative potential and in an opposite direction to that of the electrons. In an INTRINSIC semiconductor (one which does not contain any impurities), the number of holes always equals the number of conducting electrons.

Semiconductor Conduction Process

Semiconductor Conduction ProcessDoping allows control in the conduction characteristics of intrinsic semiconductor.

QuestionsThe movement of electrons in a semiconductor toward the applied voltage is termed1. hole flow 2. positive conduction 3. negative conduction 4. electron current flow

QuestionsWhat process takes place within the semiconductor to cause hole flow?1. The breaking of covalent bonds 2. The combining of valence bands 3. The flexing of the material 4. The splitting of atoms

QuestionsA material which has an equal number of electron-hole pairs and conducting electrons is known as what type of semiconductor material?1. Extrinsic 2. Intrinsic 3. N-type 4. P-type

QuestionsThe process of adding impurities to crystals is known by which of the following terms?1. Charging 2. Doping 3. Honing 4. Processing

QuestionsThe semiconductor doping impurities arsenic, antimony, and bismuthare classified as what type of impurities?1. Active 2. Neutral 3. Trivalent 4. Pentavalent

QuestionsIn the P-type semiconductor, what are the majority carriers?1. The electrons 2. The holes 3. The inactive atoms 4. The inert atoms


Semiconductor The PN JunctionThe SEMICONDUCTOR DIODE, also known as a PN JUNCTION DIODE, is a two-element semiconductor device that makes use of the rectifying properties of a PN junction to convert alternating current into direct current by permitting current flow in only one direction. A PN JUNCTION CONSTRUCTION varies from one manufacturer to the next. Some of the more commonly used manufacturing techniques are: GROWN, ALLOY or FUSEDALLOY, DIFFUSED, and POINT-CONTACT.

Semiconductor The PN JunctionJunction Barrier

Forward Bias

Semiconductor The PN JunctionReverse Bias

Semiconductor The PN JunctionThe Diode Models:Piecewise-linear modelVt + R + ideal

Simplified modelVt + ideal

Ideal

Semiconductor The PN JunctionDiode Resistance LevelsStatic ResistanceAlso called DC resistance Follows the Ohms Law

AC ResistanceDynamic Resistance Based on the thermal voltage of the semiconductor

Average ResistancePoint-to-point limits for the operating region

Semiconductor DeratingsDiodes forward voltage and power handling capability is affected by temperature. This is called Derating

QuestionsWhen the theory of semiconductors is discussed, what term(s) is/are used to describe the current that flows in the semiconductor?1. Hole flow 2. Electron flow 3. Both 1 and 2 above 4. Electromotive flow

QuestionsThe placing of an impurity on a semiconductor of the opposite impurity and fusing the two together produce what type of semiconductor junction?1. Grown junction 2. Alloy Junction 3. Barrier junction 4. Intrinsic junction

QuestionsA perfect bond at the junction of the two diode materials is important for which of the following reasons?1. It is the point at which rectification takes place 2. It is the point at which amplification takes place 3. It is the main structural point from where the diode gets its strength 4. All of the above

QuestionsCurrent flow in a copper wire can be compared to current flow in what type(s) of semiconductor material?1. N-type only 2. P-type only 3. N- and P-type 4. All types

QuestionsWhat causes the process called junction recombination to occur when N and P materials are joined together?1. The diffusion of electrons and holes moving across the junction into the two materials 2. The generation of heat which causes the electrons to bombard the holes at the junction 3. The development of an electrostatic field on each side of the junction 4. The loss of electrons to the depletion region

QuestionsAfter the junction recombination process has reached equilibrium, what is the area that surrounds the junction called?1. The anode 2. The free ion space 3. The depletion region 4. The electrostatic field

QuestionsIn a forward-biased PN junction, when an electron leaves the negative terminal of the battery and enters the N material, it becomes what type of carrier?1. Loop 2. Signal 3. Majority 4. Minority

QuestionsIn the PN junction, which of the following actions will increase the number of majority carriers and increase current flow in a forward-biased condition?1. Increasing the size of the P material 2. Decreasing the size of the P material 3. Increasing battery voltage 4. Decreasing battery voltage

Questions Diodes Transfer Curve

QuestionsWhat will happen if the voltage potential in a forward-biased diode is increased?1. Diodes forward voltage will increase 2. Diodes voltage drop will decrease 3. Current passing through the diode remain constant 4. Current passing through the diode increases

QuestionsA voltage applied to a PN junction so that it will increase the junction is called what type of bias?1. Direct 2. Forward 3. Reverse 4. Indirect


Semiconductor Diodes Types Depending on JunctionPoint-contact diodeN-type slab material and point-contact ptype material

Junction diodesN-type and p-type junction

Schottky diodeMetal and semiconductor junction

Semiconductor Diodes Types Based on Characteristic

Semiconductor Diodes Types Based on CharacteristicZener Diodea special kind of diode which allows current to flow in the forward direction in the same manner as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, "zener knee voltage" or "zener voltage. Common applications include providing a reference voltage for voltage regulators, or to protect other semiconductor devices from momentary voltage pulses.

Semiconductor Diodes Zener Diode

Semiconductor Diodes Types Based on CharacteristicAvalanche Diodea diode (made from silicon or other semiconductor) that is designed to go through avalanche breakdown at a specified reverse bias voltage. The junction of an avalanche diode is designed to prevent current concentration at hot spots, so that the diode is undamaged by the breakdown. The avalanche breakdown is due to minority carriers accelerated enough to create ionization in the crystal lattice, producing more carriers which in turn create more ionization. Because the avalanche breakdown is uniform across the whole junction, the breakdown voltage is more nearly constant with changing current compared to a non-avalanche diode.

Semiconductor Diodes Avalanche Diode

Semiconductor Diodes Zener or Avalanche?Zener Diode Means of Reverse Zener Effect voltage conduction Doping Breakdown Voltage Heavily Doped Few tens of Volts Avalanche Diode Avalanche Effect Lightly Doped Even up to ~4000V

Semiconductor Diodes Types Based on CharacteristicCats-whisker or Crystal DiodeThese are a type of point-contact diode. The cats whisker diode consists of a thin or sharpened metal wire pressed against a semiconducting crystal, typically galena or a piece of coal. The wire forms the anode and the crystal forms the cathode. Cats whisker diodes were also called crystal diodes and found application in crystal radio receivers. Cats whisker diodes are generally obsolete.

Semiconductor Diodes Cats Whiskers/Crystal Diode

Semiconductor Diodes Types Based on CharacteristicConstant Current DiodesThese are actually a JFET with the gate shorted to the source, and function like a two-terminal current-limiter analog to the Zener diode, which is limiting voltage. They allow a current through them to rise to a certain value, and then level off at a specific value. Also called CLDs, constantcurrent diodes, diode-connected transistors, or current-regulating diodes.

Semiconductor Diodes Types Based on CharacteristicTunnel or (Leo) Esaki Diodesa type of semiconductor diode which is capable of very fast operation, well into the microwave frequency region, by using quantum mechanical effect called tunneling. These diodes have a heavily doped pn junction only some 10 nm (100 ) wide. The heavy doping results in a broken bandgap, where conduction band electron states on the n-side are more or less aligned with valence band hole states on the p-side.

Semiconductor Diodes Cats Whiskers/Crystal Diode

Semiconductor Diodes Types Based on CharacteristicGunn Diodes or Transferred Electron Device (TED)a form of diode used in high-frequency electronics. It is somewhat unusual in that it consists only of N-doped semiconductor material, whereas most diodes consist of both P and N-doped regions. In the Gunn diode, three regions exist: two of them are heavily N-doped on each terminal, with a thin layer of lightly doped material in between.

Semiconductor Diodes Types Based on CharacteristicA light-emitting diode (LED)a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted lowintensity red light, but modern versions are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.

Semiconductor Diodes Types Based on CharacteristicA photodiode (or PhotoVoltaic Cell)a type of photodetector capable of converting light into either current or voltage, depending upon the mode of operation. The common, traditional solar cell used to generate electric solar power is a large area photodiode.

Semiconductor Diodes Types Based on CharacteristicPin DiodeA PIN diode has a central un-doped, or intrinsic, layer, forming a p-type/intrinsic/n-type structure. They are used as radio frequency switches and attenuators. They are also used as large volume ionizing radiation detectors and as photodetectors. PIN diodes are also used in power electronics, as their central layer can withstand high voltages. Furthermore, the PIN structure can be found in many power semiconductor devices, such as IGBTs, power MOSFETs, and thyristors.

Semiconductor Diodes Types Based on CharacteristicSnap-off or Step recovery diodesThe term step recovery relates to the form of the reverse recovery characteristic of these devices. After a forward current has been passing in an SRD and the current is interrupted or reversed, the reverse conduction will cease very abruptly (as in a step waveform). SRDs can, therefore, provide very fast voltage transitions by the very sudden disappearance of the charge carriers.

Semiconductor Diodes Types Based on CharacteristicTransient voltage suppression diode (TVS)These are avalanche diodes designed specifically to protect other semiconductor devices from high-voltage transients. Their pn junctions have a much larger crosssectional area than those of a normal diode, allowing them to conduct large currents to ground without sustaining damage.

Semiconductor Diodes Types Based on CharacteristicVaricap or varactor diodesThese are used as voltage-controlled capacitors. These are important in PLL (phaselocked loop) and FLL (frequency-locked loop) circuits, allowing tuning circuits, such as those in television receivers, to lock quickly. They also enabled tunable oscillators in early discrete tuning of radios, where a cheap and stable, but fixed-frequency, crystal oscillator provided the reference frequency for a voltage-controlled oscillator.

QuestionsSignal diodes are used for which of the following purposes?1. As mixers 2. As switches 3. As detectors 4. Each of the above

QuestionsWhat type of bias makes a diode act as an open switch?1. Direct 2. Reverse 3. Forward 4. Switching

QuestionsThe number 3N345 identifies which of the following semiconductors, if any?1. Diode 2. Transistor 3. Tetrode transistor 4. None of the above

QuestionsOne of the prime dangers to the semiconductor diode is heat. Excessive current generated by heat which eventually destroys a diode is called1. junction overload 2. thermal runaway 3. thermoplastic action 4. thermionic emission

QuestionsWhen replacing a diode in a circuit, which of the following safety precautions should you observe in removing the diode from the circuit?1. Do not pry the diode from the circuit 2. Do not use excessive heat to remove the diode 3. Do not remove the diode from the circuit while voltage is applied 4. All of the above

QuestionsAs you make a front-to-back ratio check of a diode with an ohmmeter, your first measurement (forward) is a low resistance reading, and your second measurement (reverse) is also a low reading. What should be your evaluation of the diode?1. It is open 2. It is shorted 3. It is good 4. It is leaky

QuestionsWhat are normally the front-to-back ratio of (a) a power rectifier and (b) a signal diode?1. (a) 10:1 (b) 50:1 2. (a) 10:1 (b) 300:1 3. (a) 300:1 (b) 10:1 4. (a) 300:1 (b) 50:1

QuestionsWhat term is used for a semiconductor that has three or more elements?1. Diode 2. Transistor 3. Duo-diode 4. Point contact


Semiconductor Diodes ParametersDIODE RATINGSare the limiting value of operating conditions of a diode. Operation of the diode outside of its operating limits could damage the diode. Diodes are generally rated for: MAXIMUM AVERAGE FORWARD CURRENT, PEAK RECURRENT FORWARD CURRENT, MAXIMUM SURGE CURRENT PEAK REVERSE VOLTAGE (PIV)

Semiconductor Diodes RectificationRectificationProcess of converting AC to DC.

Semiconductor Diodes Rectification

QuestionsIf the input frequency to a half-wave rectifier is 120 hertz, what is the output frequency of the rectified dc?1. 30 pps 2. 60 pps 3. 120 pps 4. 240 pps

QuestionsGiven a series circuit of Diode-ResistorDC_Voltage, What is the voltage across a diode with any positive value of I? What is the current in a diode with any positive value of V?

Semiconductor Diodes Voltage Clipper and ClamperClipperhave the ability to clip off a portion of the input signal without distorting the remaining part of the alternating waveform

ClamperA network is one that will clamp a signal to a different dc level Also called a DC restorer

Semiconductor Diodes Voltage Multiplier Circuits

Solid State Devices: Bipolar Junction TransistorsPresented by: Jupelm Alesna EcE #46806

Transistor DefineWhat is a transistor?is a three or more element solid-state device that amplifies by controlling the flow of current carriers (hole and electron) through its semiconductor materials. Its function is generally govern by the following:Rectification Amplification Mixing Oscillation Switching

Bipolar Junction Transistor TypesTwo types of transistor based on their construction is the PNP and the NPN. Transistor has 3 terminals namely the Emitter, Base, and Collector Since it has 2 junction, coding for transistor follows the form 2NXXXX

Bipolar Junction Transistor Basic OperationNote: The diagram follows the conventional current flow

Bipolar Junction Transistor Regions of Operation

Bipolar Junction Transistor Regions of OperationApplied voltages Bias (NPN) EC Applied voltages Bias (PNP) EC B-E Junction Forward Forward Reverse Reverse B-C Junction Reverse Forward Reverse Forward Mode (NPN) Forward-active Saturation Cut-off Reverse-active

B-E Junction Reverse Reverse Forward Forward

B-C Junction Forward Reverse Forward Reverse

Mode (PNP) Reverse-active Cut-off Saturation Forward-active

Bipolar Junction Transistor ConfigurationAmplifier Type Input-output relationship Voltage Gain Current Gain Power Gain Input Resistance Output Resistance Common Base 0 High Low (alpha) low low high Common Emitter 180 Medium Common Collector/ Emitter Follower 0 Low

Medium (beta) High (gamma) high High to medium Medium High

Medium to low Low

Bipolar Junction Transistor ConfigurationGAIN is a term used to describe the amplification capabilities of an amplifier. It is basically a ratio of output to input. The current gain for the three transistor configurations (CB, CE, and CC) are ALPHA (), BETA (), and GAMMA (), respectively

I C = IE

I C = IB

IE = IB

Bipolar Junction Transistor Basic BiasingFixed Bias Emitter-Stabilized Bias Voltage Divider Bias

Fixed Bias

Emitter-Stabilized Bias

Voltage Divider Bias

QuestionsThe term transistor was derived from which of the following words? 1. Resistance and capacitance 2. Transformer and resistor 3. Resistor and transformer 4. Transfer and resistor

In a transistor schematic, what is indicated by (a) the angular line with the arrowhead and (b) the direction of the arrow? 1. (a) Cathode (b) Direction of current flow 2. (a) Base (b) Direction of current flow 3. (a) Emitter (b) Type of transistor 4. (a) Collector (b) Type of transistor

Junction transistors have replaced pointcontact transistors for which of the following reasons? 1. Junction transistors generate less noise 2. Junction transistors handle more power 3. Junction transistors provide higher current and voltage gains 4. All of the above

What is the total number of PN junctions in a transistor? 1. One 2. Two 3. Three 4. Four

What is the total number of semiconductor layer in a transistor? 1. One 2. Two 3. Three 4. Four

What are the two junctions of a transistor? 1. Emitter-base and emitter-collector 2. Emitter-collector and base-collector 3. Emitter-base and collector-emitter 4. Emitter-base and base-collector

With proper bias applied to a transistor, what should be the relative resistance of (a) the emitter-base junction and (b) the base-collector junction? 1. (a) High (b) low 2. (a) High (b) high 3. (a) Low (b) low 4. (a) Low (b) high

For normal operation of a transistor, what is the bias of the (a) emitter-base junction and (b) base-collector junction? 1. (a) Forward (b) reverse 2. (a) Forward (b) forward 3. (a) Reverse (b) forward 4. (a) Reverse (b) reverse

In a transistor, what percent of the total current flows through the emitter lead? 1. 100 2. 98 3. 60 4. 5

What are the majority current carriers in (a) the PNP transistor and (b) the NPN transistor? 1. (a) Holes (b) holes 2. (a) Holes (b) electrons 3. (a) Elements (b) holes 4. (a) Electrons (b) electrons

How will the transistor currents be affected if the forward bias provided by VBB is increased? 1. IB will decrease, IE will decrease, and IC will decrease 2. IB will increase, IE will decrease, and IC will decrease 3. IB will increase, IE will decrease, and IC will increase 4. IB will increase, IE will increase, and IC will increase

What device provides an increase in current, voltage, or power of a signal without appreciably altering the original signal? 1. Diode 2. Amplifier 3. Oscillator 4. Power supply

. Which of the following is a transistor configuration that provides a phase reversal? 1. Common bias 2. Common input 3. Common emitter 4. Common collector

What is the symbol for input current in a common-emitter configuration? 1. IE 2. IB 3. IC 4. IT

What is the symbol for input current in a common-base configuration? 1. IE 2. IB 3. IC 4. IT

What term is used to indicate current gain in a common-collector configuration? 1. Alpha 2. Beta 3. Gamma 4. X-ray

The common collector is also referred to by which of the following terms? 1. Low current gain amplifier 2. Voltage amplifier 3. Emitter follower 4. Grounded emitter

Which of the following conditions presents the greatest danger to a transistor? 1. Heat 2. High operating voltage 3. Excessive reverse current 4. Handling of the transistor

What method for checking transistors is cumbersome when more than one transistor is bad in a circuit? 1. Ohmmeter 2. Transistor checker 3. Voltage check 4. Substitution

Solid Stated Devices: FETPresented by: Jupelm Alesna EcE #46806

Field Effect Transistor DefineThis is a type of transistor that controls its output by generating an Electric Field. Applications of FET extends to all applications of BJT, with some limitations of course. There are two types of FET, the Junction FET and the Metal Oxide Semiconductor FET. The main difference is in their construction.

Junction Field Effect Transistor Construction and Operation

Channel is skewed

The transfer characteristics defined by Shockleys equation are unaffected by the network in which the device is employed

Dynamic Resistance at the Ohmic Region

MOSFET Construction and OperationMain difference from JFET is the insulation at the gate terminal. Types:Depletion Type Enhancement Type

Channels:N-channel P-channel Complementary MOSFET (CMOS)

Depletion Type

Notice the enhancement region

Enhancement type

Enhancement Type Transfer and VDS Curve

MOSFET HandlingThe SiO2 layer at the gate of the CMOS offers a very high impedance input. For this to happen (and for appropriate electric field to be generated), this dielectric layer should be very thin. Because of this, the gate of the CMOS is very vulnerable to ESD, transients, and voltage spikes.

VMOSThe main disadvantage of MOSFET is reduced power capacity. This is resolved by decreasing the channel resistance, as in VMOS.

CMOS

Solid State Devices: AmplifiersPresented by: Jupelm Alesna EcE #46806

Amplifier DefineAn amplifier receives a signal from some pickup transducer or other input source and provides a larger version of the signal to some output device or to another amplifier stage.

Amplifier Classes

FiltersPresented by: Jupelm Alesna EcE #46806

Filters DefineA filter is a device or process that removes from a signal some unwanted component or feature. Filtering is a class of signal processing, the defining feature of filters being the complete or partial suppression of some aspect of the signal. Most often, this means removing some frequencies and not others in order to suppress interfering signals and reduce background noise.

Families of Filter

Bandform of FiltersLow-pass filter low frequencies are passed, high frequencies are attenuated. High-pass filter high frequencies are passed, low frequencies are attenuated. Band-pass filter only frequencies in a frequency band are passed. Band-stop filter or band-reject filter only frequencies in a frequency band are attenuated. Notch filter rejects just one specific frequency an extreme band-stop filter. Comb filter has multiple regularly spaced narrow passbands giving the bandform the appearance of a comb. All-pass filter all frequencies are passed, but the phase of the output is modified.

Uni-Junction Transistor

Uni-Junction Transistor DefineThe UNIJUNCTION TRANSISTOR (UJT), originally called a double-based diode, is a threeterminal, solid-state device that has several advantages over conventional transistors. It is very stable over a wide range of temperatures and allows a reduction of components when used in place of conventional transistors.

UJT Construction

UJT Biasing

Voltage RegulatorsPresented by: Jupelm Alesna EcE #46806

Voltage Regulator DefineA voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. The output voltage can only be held roughly constant; the regulation is specified by two measurements:load regulation or Voltage Regulation line regulation or input regulation

Voltage Regulator Other ParametersTemperature coefficient Initial accuracy Dropout voltage Absolute maximum ratings Output noise (thermal white noise) and output dynamic impedance Quiescent current Transient response Mirror-image Insertion Protection

Voltage Regulators TypesStabilizerUses Shunt/Series Regulator such as Zener Diodes/Transistor

Active RegulatorsLinear RegulatorFixed Variable

Switching Regulator

Voltage Regulator Switching RegulatorsType Power Typical Energy [W] efficiency storage 0 8090% 1,000 0150 70% 0150 78% Voltage relation Features Single 0 Out In, Current is continuous at output. inductor Single Out In, Current is continuous at input. inductor Single Out 0, inductor Current is dis-continuous at both input and output. Low performance. Like a CW multiplier, the disadvantages of charge pumps for power conversion can be somewhat mitigated through proper component sizing and drive frequency, since output energy is proportional to capacitance and frequency.

Buck Boost Buckboost

Charge pump

Capacit ors only

Buck

Boost

Buck-Boost

OscillatorPresented by: Jupelm Alesna EcE #46806

Oscillator DefineAn oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave. Two kinds of oscillator are relaxation oscillators and harmonic oscillator

Relaxation OscillatorRO using a UJT

Harmonic OscillatorThe harmonic, or linear, oscillator produces a sinusoidal output Often characterized by the frequency of their output signal: an audio oscillator produces frequencies in the audio range, about 16 Hz to 20 kHz. An RF oscillator produces signals in the radio frequency (RF) range of about 100 kHz to 100 GHz. A low-frequency oscillator (LFO) is an electronic oscillator that generates a frequency below 20 Hz. Oscillators designed to produce a high-power AC output from a DC supply are usually called inverters.

Harmonics Oscillator ClassificationHarmonic oscillator circuits can be classified according to the type of frequency selective filter they use in the feedback loopRC oscillator LC oscillator Crystal oscillator

Harmonics Oscillator Other TypesArmstrong oscillator Clapp oscillator Hartley Collpits Oscillator

Documents

Soild State Review