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Reference Guide

Permachart - Marketing Reference Guide: Charge Pump, Diode, Electrolytic Capacitor

4 pages146 viewsFall 2015

Department
Electrical Engineering
Course Code
4400:307
Professor
All
Chapter
Permachart

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w w w . p e r m a c h a r t s . c o m
Conductors & Semiconductors
Conductors & Semiconductors
BA SI CS TERMS
EL EC TR IC CI RC UI T AP PL IC ATI ON S OF OR DI NA RY DI OD ES
RECTIFIERS
• Rectifiers may be
half-wave or
full-wave
• A half-wave cuts
off the bottom
(or top) of the
input signal
• A full-wave flips
bottom of signal
so that both
positive and
negative halves
of the AC wave
appear across
load resistor
• Half-wave
rectifiers produce
an output signal
with a
fundamental
frequency that
is same as input
AC signal
• Full-wave rectifiers
double the input
AC signal
frequency
• An operational amplifier may be combined with a physical diode to produce a circuit
that responds like a perfect diode, which is also known as an active full/half-wave
rectifier
• This circuit overcomes forward voltage drop of the conducting diode
• In an active half-wave rectifier, D1s characteristics are being improved, while D2only
provides a current feedback path around the amplifier when D1is not conducting
• Power supply applications commonly use a
transformer to isolate the power supply from a
110-V AC line
• A half-wave rectifier may be connected to the
transformer secondary (as shown) to generate
typical half-wave output signal
Conductor Valence and conduction bands for electrons
overlap at room temperature, allowing relatively
free movement of electrons
Semiconductor Valence and conduction bands have an energy
gap that can be jumped by a significant number
of thermally excited electrons at room
temperature, making these materials
semiconductors
• Common semiconductor materials include
silicon and germanium
N-type Material Majority of free charge carriers in semiconductor
material are negative
P-type Material Majority of free charge carriers in semiconductor
material are positive
Doping Mixing in a few atoms of a different material into
a semiconductor material, in order to generate
more charge carriers (such as, doping a crystal of
pure silicon with arsenic atoms to form N-type
material)
PN Junction Junction of P- and N-type semiconductor materials
which develop an electric field across the junction
that repels both majority carriers away from the
junction
Diode Two semiconductor materials fabricated in the
form of a PN junction with a semiconductor-metal
junction at each end
Zener Diode Diode constructed so increase in current in reverse
direction (when diode is reverse-biased) will be
non-destructive
Frequency Cycles per second f= 1/t
• Symbol = f
• Units = hertz (Hz or s-1)
Resistance A measure of the opposition to current flow
• Symbol = RUnits = Ohm (W)
Forward-/ Connection across a PN junction • In forward- bias,
Reverse-biasing current flows from P-type material to N-type
• In reverse-bias, current flows from N-type
material to P-type
Capacitance Ability to store electric charge Symbol = C
• Units = Farad (F)
Electric Current A measure of the flow of electrons • Symbol = I
• Unit = Ampere (A)
Insulator Valence and conduction bands for electrons do
not overlap at room temperature, and have an
energy gap that cannot be jumped by electrons at
room temperature; this does not allow movement of
electrons, making these materials insulators
CONDUCTORS & SEMICONDUCTORS • 1-55080-808-7 1© 1996-2010 Mindsource Technologies Inc.
l e a r n r e f e r e n c e r e v i e w
TM
permacharts
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