Class Notes (806,815)
United States (312,228)
4400:307 (5)
All (5)
Reference Guide

Electronics I - Reference Guides

2 Pages
Unlock Document

University of Akron
Electrical Engineering

permacharts TM E le c t r o n ic sI Waveforms Diodes Equivalent Circuits • Diodes are 2-terminal devices that pass current in 1 d• Any two-terminal linear circuit can be replaced by a single •When a large enough reverse voltage is applied to any diode,age source in series with single resistance (Thevenin it will conduct current in the reverse direction (breakdown)uit) or current source in parallel with resistor (Norton circuit) Germanium Diodes Advantage: Forward voltage drop for silicon diodes is about 0.7V,compared to 0.3V for germanium diodes Disadvantage: Breakdown voltages for germanium diodes are usually less than 100V,compared to 50–1000V for silicon FOURIER SERIES & FOURIER TRANSFORM Ieal diode: Diode is either an open circuit or a short circuit • A Fourier series applies to signal waveforms that are periodic Semiconductor Junctions functions of time • A periodic signal with a complex waveform has a discrete P-N JUNCTIONS sectrum of harmonic (sine/cosine) waveforms of magnitudes N-type: Semiconductor doped with donors (phosphorus,arsenic, determined by Fourier series antimony) which have loosely bound electrons • A Fourier transform applies to signal waveforms that are P-type: Semiconductor doped with acceptors (boron,gallium, non-periodic functions of time ZENER DIODE indium) which have atoms that leave an electron vacancy (hole) • A non-periodic waveform has a continuous spectrum of Hole: The mobile positive charge in semiconductor materials harmonic components determined by Fourier transform • Diode designed to operate in the breakdown region; Doping: The process of adding a controlled amount of a specific LAPLACE TRANSFORM used to establish a fixed DC voltage or limit a impurity to control a material’s conductivity varying signal to a peak voltage • Laplace transform applies only to time functions that • Constructed to work in the reverse-bias direction Forward bias: Voltage required to turn on a pn junction fr t < 0; it implicates complex frequency s = j + •Zener diode is not in breakdown if reverse-bias current iserse bias: Voltage applied to a pn junction that prevents the junction from conducting insufficient; instead,it will act as an open circuit • In the presence of an electric field, Semiconductor Devices SCHOTTKY DIODE a hole takes an electron from an • Metal semiconductor junction diode atom of silicon (usual A K semiconductor material) • Has low 0.3V forward voltage drop Diode or Zener diodepolar voltage lTunnel diode • Al or Pt may act as acceptor when in contact with n-type Sis event is repeated in a metallic rectifier (symmetrical zener diode) consistent direction, LIGHT-EMITTING DIODE (LED) resulting in conduction by hole • A diode that will emit visible or infrared light when sufficient forward voltage is applied Pin diode(photosensitive diode (LED)nsensitive diode • When injected,minority carriers in forward-biased pn junction recombine to release energy K A A K T T T T •With Si and Ge,energy is released as heat Trigger diac Trigger diac BidirectionaBidirectional • With GaAs,energy is released as photon at red,yellow or (npn) (pnp) trigger diac trigger diac (pnp)green wavelengths (depending on impurities added) m o or E C E C PHOTODIODE (LIGHT-SENSITIVE DIODE) E C E C B B • A diode that produces a current or a voltage in c B Transistor Transistor response to light BIPOLAR SEMICONDUCTOR . Phototransistor (npn) (pnp) (npn) • Reverse saturation current depends on generation • An npn transistor consisting of two junctions; a p-type material G G G of hole-electron pairs by average thermal energy of the crystaled between two n-type materials s A K A K T T t n-type gate p-type gate Thyristor • Current can be increased further by light illumination• Almost all of the electrons injected from the emitter intorthe Semiconductor controlled rectifbidirectional triode VARACTOR (VARICAP DIODE) thin base region are collected by the collector • A diode that acts as a capacitance controlled a or by the reverse-bias voltage h Darling on-type tranpnp transverse-biased base transistorforward bias due to high shunt conductance c a Diodes in Circuits m Clipper: Acircuit that FULL-WAVE BRIDGE RECTIFIER regulates voltage by • Convert to DC power supply by FIELD-EFFECT TRANSISTOR (FET) r eliminating any part of a putting capacitor parallel with R• A doped semiconductor provides a channel for flow of current signal that is greater in L from drain D to source S; p-type at the center controls current magnitude than set voltageDiode bridge: Four diodes connecte• Positive voltage applied to D causes I downwards p Rectification: as a bridge (i.e.,electrons upwards) D Elimination of circuit to positive or provide for • When negative voltage is applied to G,junction is reverse-biased; negative portion full-wave depletion region eliminates conduction electrons from channel of signal rectification • FET has very small gate current and low voltage gain 2 Half-wave rectifier: Uses only one-half of input cycle; negative half of sine wave is lost  vGS Full-wave rectifier: Uses all of input cycle; efficiency increases as all incoming ac is used S SD D= − 1 V   P  PEAK DETECTOR ENVELOPE DETECTOR dD 2DSS  vGS  •A peak detector is a circuit that hold the peak value of the in• Envelope detector used inAM radio circuits to gm ≡ =dv −V 1 − V  • The capacitor in a peak detector most hold its charge for the duration ofw frequency audio envelope modulated on GS P  P  the signal measurement a high frequency carrier I Vg I = − • Rate of change of vt satisfyedt 1 SP S Dm D () • IfCRproduct is very l3rge,v equals the highes2 peaks in v e C v R 〈 • IfCR product is small en3ugh,v will be able to follow t2e envelope of v e • Biasing the FET means • Peak detector is used in radio receiver as automatic gain control to select a point on the curve around which it will operate permacharts TM Transistors Diodes in Circuits • A transistor is a three-terminal semiconductor device that C OMMON EMITTER (cont’d) amplifies electrical signals when in its active state • Most common configuration for • For npn transistor to stay in active staCe, v ≤ v a amplification VOLTAGE REGULATOR When A Zener Diode Is In Shunt With The Load • Has both high voltage and current gain • Voltage gain is greatest when an • Rdd(opping resistor) is chosen at emitter bypass capacitor is used Zmin(necessary to maintaiZ ) , vcc ,and R Lmin L is maximum) • Load voltage vis nearly constant, dnatuWht i C2 3 C , L
More Less

Related notes for 4400:307

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.