Eee Formula on Courtessy

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  • Topic: Diode, Transistor, Bipolar junction transistor
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electronic Devices AND Circuits

BRIEF NOTES

UNIT – I :: ELECTRON DYNAMICS: CRO

➢ [pic], ‘F’ force on electron in uniform electric field ‘E’ ➢ F=eE; acceleration [pic]
➢ If electron with velocity [pic] moves in field [pic] making an angle [pic] can be resolved to [pic]. ➢ Effect of Magnetic Field ‘B’ on Electron.
➢ When B & Q are perpendicular path is circular [pic]
➢ When slant with [pic] path is # Helical.
➢ EQUATIONS OF CRT
➢ ELECTROSTATIC DEFLECTION SENSITIVITY [pic]
➢ MAGNETIC DEFLECTION SENSITIVITY [pic]
➢ Velocity due to voltage V, [pic]
➢ When E and B are perpendicular and initial velocity of electron is zero, the path is Cycloidal in plane perpendicular to B & E. Diameter of Cycloid=2Q, where [pic], [pic], [pic].

UNIT – II :: SEMICONDUCTOR JUNCTION

➢ [pic] have 4 electrons in covalent bands. Valency of 4. Doping with trivalent elements makes [pic], Pentavalent elements makes [pic] semiconductor. ➢ Conductivity [pic] where [pic] are concentrations of Dopants. [pic] are mobility’s of electron and hole respectively.

[pic]

[pic]

➢ [pic]

➢ [pic]

➢ Diode drop changes [pic], Leakage current [pic] doubles on [pic] [pic]

➢ Diffusion capacitance is [pic] of forward biased diode it is [pic]

➢ Transition capacitance [pic] is capacitance of reverse biased diode [pic] [pic]

➢ RECTIFIERS
[pic]

➢ COMPARISION

| |HW |FW CT |FW BR | |[pic] |[pic] |[pic] |[pic] | |[pic] |[pic] |[pic] |[pic] | |[pic] |[pic] |[pic] |[pic] | |Ripple factor | | | | |[pic] |[pic] |[pic] |[pic] | |Rectification efficiency | | | | |[pic] |[pic] |2[pic] |[pic] | |Peak Inverse Voltage | | | |

UNIT – III :: FILTERS

➢ Harmonic Components in FW Output, [pic]

[pic]

[pic]

[pic]

[pic]

[pic]

[pic]

➢ ZENER DIODE

[pic]

➢ ZENER REGULATOR

➢ [pic]

➢ [pic]

➢ TUNNEL DIODE

[pic]

➢ Conducts in [pic], Quantum mechanical tunneling in region a-0-b-c. ➢ -ve resistance b-c, normal diode c-d.
[pic]= peak current, [pic]= valley current; [pic]=peak voltage ≈ 65 mV, [pic]=valley voltage 0.35 V. Heavy Doping, Narrow Junction , Used for switching & HF oscillators.

➢ VARACTOR DIODE

Used in reverse bias & as tuning variable capacitance.

➢ [pic]; n=0.3 for diffusion, n=0.5 for alloy junction, [pic] ➢ [pic] is figure of merit, Self resonance [pic]

➢ PHOTO DIODES

➢ Diode used in reverse bias for light detection.

➢ Different materials have individual peak response to a range of wave lengths.

UNIT - IV

➢ BJT, Bipolar Junction Transistor has 2 Junctions: BE, BC ➢ Components of current are [pic] at [pic] junction where [pic] ➢ [pic]Emitter efficiency, [pic] transportation factor.

➢ [pic]

[pic][pic]

[pic][pic]

➢ Leakage currents : [pic]
➢ [pic]

➢ 3 Configurations are used on BJT, CE, CB & CC


➢ Common Emitter, VI characteristics

➢ [pic]

[pic]

AC Equivalent Circuit

➢ COMMON BASE VI CHARACTERISTICS

[pic] [pic]

➢ [pic]

➢ [pic]...
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