electrostatics and magnetostatics nathaniel j. c. libatique, ph.d. [email protected] 3 december...
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f f c c
Fields and WavesFields and Waves
Statics: very importantStatics: very important
Magnetic Storage: HDD TechnologyMagnetic Storage: HDD Technology Fields in transmission linesFields in transmission lines MEMS actuatorsMEMS actuators E-InkE-Ink Electrostatic separationElectrostatic separation ESDESD
HDDsHDDs
http://www.pcworld.com/article/128400/hitachi_introduces_1terabyte_hard_drive.html
Hitachi Introduces 1-Terabyte Hard Drive
Colossal storage reaches new milestone with a drive that holds 1000 gigabytes.Melissa J. Perenson, PC World
Jan 5, 2007 1:00 pm
Hitachi Global Storage Technologies is first to the mat with an announcement of a 1-terabyte hard disk drive. Industry analysts widely expected a 1TB drive to ship sometime in 2007; Hitachi grabbed a head start on the competition by announcing its drive today, just before the largest U.S. consumer electronics show starts next week.
ESDESD
Photos from Rohm Electronics
This failed IC was one of several rejected as low input resistance (leaky) at a particular input pin. Sectioning in Japan identified the partial short through the silicon from the top as shown by the small well on the track i.e. top of short circuit.
This transistor was also confirmed failed by ESD. You can see where the discharge energy surge has buried through the weakest point(s) in the oxide layer through to the silicon. Bipolar devices are becoming very small and susceptible to ESD.
http://www.electrostatics.net/library/articles/ESD_damage.htm
mcgonnigle.files.wordpress.com/2007/02/lightning.jpg
Fields in Transmission Fields in Transmission LinesLines
Two-wire
Coaxial
Microstrip
Triplate
E-InkE-Ink
http://www.eink.com/technology/howitworks.html
MEMSMEMS
http://mems.sandia.gov/gallery/images/m10.jpg
Capacitors and InductorsCapacitors and Inductors
Capacitors store electric fluxCapacitors store electric flux Q = CVQ = CV, , i = CdV/dti = CdV/dt Charging up a capacitor: Charging up a capacitor: = RC = RC
Inductors store magnetic fluxInductors store magnetic flux = LI, v = Ldi/dt= LI, v = Ldi/dt Fluxing up an inductor: Fluxing up an inductor: = L/R = L/R
DemonstrationsDemonstrations
Faraday’s LawFaraday’s Law Lorentz ForceLorentz Force
Conducting rod in a magnetic fieldConducting rod in a magnetic field Deflecting electrons in a CRT via Deflecting electrons in a CRT via
magnets magnets Induced fields and currents in a 5 Induced fields and currents in a 5
turn loopturn loop
How does one “see” How does one “see” an electric or magnetic an electric or magnetic
field?field? Fields give rise to measurable forcesFields give rise to measurable forces Static fields create “other” static Static fields create “other” static
fieldsfields Dynamic fields give rise to “other” Dynamic fields give rise to “other”
time varying fieldstime varying fields
Electrostatics: Electrostatics: Coulomb’s LawCoulomb’s Law
Qo
Q1
F1
F1 =Qo Q1
4 R2
a1
F1 = Q1 E0
R
E-field source is Q0
Qe = - 1.60219 x 10-19 C
= permittivitty of free space = 8.854 x 10-12 F/m1/4o = 9 x 109 m/F
Electrostatic Field Electrostatic Field SourcesSources
Charge distributions give rise to E fieldsIt takes work to “create” charge distributions, hence charge distributions store energy.
Ampere’s Force LawAmpere’s Force Law
I1
I2
dl1
dl2Ra12
dF2
dF2 = I2 dl2
k I1 dl1 a12
R2
dF1 = I1 dl1
k I2 dl2 a21
R2
dB1
(dB) = Weber/m2 k = o/4o = magnetic permeability = 4 x 10-7 H/m
Biot-Savart LawBiot-Savart Law
Current distributions give rise to magnetic flux densities
I
dl
A
R
dB =
I dl aR
R2
Infinitely Long Straight Infinitely Long Straight WireWire
I
r
?B
B = r
a
Infinite Plane Sheet of Infinite Plane Sheet of CurrentCurrent
JS ?
B
?
B
B
B =
JS an
B
B
Superposition of manywires coming off the page…
Infinite Plane Sheet of Infinite Plane Sheet of CurrentCurrent
Lorentz ForceLorentz ForceF = q (E + v B)
• CRT
• Ink Jet Printer
• Mass Spectrometer
• Electron Microscope
• Particle Accelerators
SlingshotSlingshot
A very low concentration of sample molecules is allowed to leak into the ionization chamber (which is under a very high vacuum) where they are bombarded by a high-energy electron beam. The molecules fragment and the positive ions produced are accelerated through a charged array into an analyzing tube. The path of the charged molecules is bent by an applied magnetic field. Ions having low mass (low momentum) will be deflected most by this field and will collide with the walls of the analyzer. Likewise, high momentum ions will not be deflected enough and will also collide with the analyzer wall. Ions having the proper mass-to-charge ratio, however, will follow the path of the analyzer, exit through the slit and collide with the Collector. This generates an electric current, which is then amplified and detected. By varying the strength of the magnetic field, the mass-to-charge ratio which is analyzed can be continuously varied.
http://www.chem.uic.edu/web1/ocol/spec/MS1.htm
SampleFeed
http://www.chem.ucalgary.ca/courses/351/Carey/Ch13/ch13-ms.html
The molecular ion, again, represents loss of an electron and the peaks above the molecular ion are due to isotopic abundance. The base peak in toluene is due to loss of a hydrogen atom to form the relatively stable benzyl cation. This is thought to undergo rearrangement to form the very stable tropylium cation, and this strong peak at m/e = 91 is a hallmark of compounds containing a benzyl unit. The minor peak at m/e = 65 represents loss of neutral acetylene from the tropylium ion and the minor peaks below this arise from more complex fragmentation.
http://www.chem.uic.edu/web1/ocol/spec/MS1.htm
The mass spectrum of toluene (methyl benzene) is shown. The spectrum displays a strong molecular ion at m/e = 92, small m+1 and m+2 peaks, a base peak at m/e = 91 and an assortment of minor peaks m/e = 65 and below.
Millikan Oil DropMillikan Oil Drop
e/m = charge to mass ratioe/m = charge to mass ratio e = 1.602 × 10e = 1.602 × 10-19-19 Coulombs Coulombs
http://en.wikipedia.org/wiki/Oil-drop_experiment
ConductionConduction
http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/ohmmic.html#c1
• Electron Gas• Distribution of velocities: seen as temperature macroscopically• Electrons have mean free time between colllissions• vd = E• J = E• Resistance vs. resistivity
The common U.S. wire gauges (called AWG gauges) refer to sizes of copper wire. The resistivity of copper at 20 C is about
1.724 x 10-8 m
AWG wire size (solid)
Diameter(inches)
Resistance per1000 ft (ohms)
Resistance per1000 m (ohms)
24 0.0201 25.67 84.2
22 0.0254 16.14 52.7
20 0.0320 10.15 33.2
18 0.0403 6.385 20.9
16 0.0508 4.016 13.2
14 0.0640 2.525 8.28
12 0.0808 1.588 5.21
10 0.1019 0.999 3.28
http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/wirega.html#c1
MaterialResistivity (ohm m)
Temperaturecoefficientper degree C
Conductivity
x 107 /m
Silver 1.59 x10^-8 .0061 6.29
Copper 1.68 x10^-8 .0068 5.95
Aluminum 2.65 x10^-8 .00429 3.77
Tungsten 5.6 x10^-8 .0045 1.79
Iron 9.71 x10^-8 .00651 1.03
Platinum 10.6 x10^-8 .003927 0.943
Manganin 48.2 x10^-8 .000002 0.207
Lead 22 x10^-8 ... 0.45
Mercury 98 x10^-8 .0009 0.10
Nichrome(Ni,Fe,Cr alloy)
100 x10^-8 .0004 0.10
Constantan 49 x10^-8 ... 0.20
http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/rstiv.html#c1
Carbon*(graphite)
3-60 x10^-5 -.0005 ...
Germanium* 1-500 x10^-3 -.05 ...
Silicon* 0.1-60 ... -.07 ...
Glass 1-10000 x10^9 ... ...
Quartz(fused)
7.5 x10^17 ... ...
Hard rubber 1-100 x10^13
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/Hall.html#c2
Hall EffectHall Effect
http://content.honeywell.com/sensing/prodinfo/solidstate/technical/chapter2.pdfhttp://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/hall.html#c1http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html#c4http://www.allegromicro.com/en/Products/Design/hall-effect-sensor-ics/index.asp
Q = CV = L I
d/dt = L dI/dt
Electric field lines, magnetic flux linesCharging up a capacitor, differential equation solution, particular and homogeneousFluxing up an inductor, differential equationsUnits and Dimensions
