t****1
发帖数: 827 | 1 the original question says: if Vgs<0.7, then cut off. did the devices in your simulation really cut off? no leakage current? Of course not, if you understand what is weak inversion.So, your simulation condition is different from the assumption in that question.
Ok, now let's assume it really cuts off. no leakage current. from your
answer,if vin=0, then vout=0.7, and if vin=0.1then vout is about 0.8v. is
that correct?
My question: when vin increases from 0 to 0.1v, why Vout can not stay at 0.7v. ... 阅读全帖 |
|
f****3
发帖数: 502 | 2 首先十分感谢你的多次回帖，谢谢！先说明一下，我只是请教问题，没有对任何人的回
复有任何的态
度问题，如果我哪句话让你不爽了，请谅解！
下面说一下这个问题，我又仔细看了一些wiki里面关于crossover的阐述，wiki那张图
上面接
Vdd，下面接Vss，只有负载接Gnd，这样就比较好理解了。
如果|Vin|<0.7，两管截止，输出为0，当Vin>0.7时，上面N管导通，Vout=Vin-0.7，当
Vin<-
0.7时，下面P管导通，Vout=Vin+0.7。当相应于我这到题来讲，上面依然是Vdd，但是
下面接的
GND，所以将GND等效为Vss时，那么输出2.5V即是相应wiki的输出为0，这样就很好理解
为什么不
是一直follow，而在中间需要转换，这是我想问的问题。
但是不好意思，你一直纠结于有无负载，我承认你的思维很严谨，对问题的分析很透彻
，但你并没有
领会我的困惑，呵呵，或许我的困惑很弱智，无需回答，但同时你也并没有说出电路真
正工作的过
程，即使你一开始就给出了很合理的答案。
Anyway,依然非常感谢你的回复，再重申一遍，我对你的回复没有任何的态度上面的问
题，请... 阅读全帖 |
|
h*******a
发帖数: 184 | 3 I'll try # 1: the current, the channel resistance (or equivalent)
capacitance and the voltage determines the speed. |
|
m********e
发帖数: 585 | 4
Idon, voltage, capacitance, sub-threshold current
are we talking about? The width?
Of course the length, width is much wider.
resolution?
Don't know what you are talking about.
This is not the right question to ask. |
|
w********o
发帖数: 10088 | 5 我是觉得迁移率跟vth关系不大，vth更多的是跟参杂浓度和gate capacitance相关吧
realm |
|
c*******c
发帖数: 726 | 6 Ja, Vth~2*|Ef-Ei|+Voltage Dropped on Gate Capacitance.
Maybe it's better to consider in this way.
When T increases, the intrinsic carrier generates. At that time, the
minority carrier should be considered dominant in affecting Ef.
In NMOS P sub, holes in V band are compensated and vice verse in PMOS C band
, so |Ef-Ei| decreases and Vth decreases.
Then consider the mobility thing. Since the mobility of electron is greater
than that of hole, scattering exists more often on holes than on electrons... 阅读全帖 |
|
w********o
发帖数: 10088 | 7 我是觉得迁移率跟vth关系不大，vth更多的是跟参杂浓度和gate capacitance相关吧
realm |
|
c*******c
发帖数: 726 | 8 Ja, Vth~2*|Ef-Ei|+Voltage Dropped on Gate Capacitance.
Maybe it's better to consider in this way.
When T increases, the intrinsic carrier generates. At that time, the
minority carrier should be considered dominant in affecting Ef.
In NMOS P sub, holes in V band are compensated and vice verse in PMOS C band
, so |Ef-Ei| decreases and Vth decreases.
Then consider the mobility thing. Since the mobility of electron is greater
than that of hole, scattering exists more often on holes than on electrons... 阅读全帖 |
|
w****j
发帖数: 237 | 9 hehe,虽然是个伪命题，大家都讨论的不亦乐乎啊~
不过你的假设是错的，相对于现在手机的尺寸，覆铜很难作为一个有效的射频地，所以
手机天线的设计一定要在初始阶段就要考虑电路板的形状。这个导致基于2维无限地的
Method of moment其实不是很有效的仿真，修改后基于多层substrate的greens'
function的MoM软件好像也不是很准确。基于FDTD或者FEM的就有比较好得结果了。
另外，就算作为一般的analog ground或者digital ground，现在复杂电路板的power
plane/bus和ground plane都不能再认为是理想了，大量的power integrity软件就是为
了解决这些plane perforation, parasitic inductance, plane capacitance的问题了
，设计不好，电路通过这些覆铜的互相干扰还是很严重的~
天线,公司等背景吸引眼球而已. 能够起到抛砖引玉的作用,看到这么多有趣的回复,我
恨高兴.
和其上面的众生相比,是个无穷大的的物体,所以它就是 true ground. 在一个手机里... 阅读全帖 |
|
g****t
发帖数: 31659 | 10 手机的地都是电池的负极.本身就是一层层材料卷起来的,面积很大.
PCB覆铜啥的,对电池负极的电压影响应该是微乎其微的吧.
hehe,虽然是个伪命题，大家都讨论的不亦乐乎啊~
不过你的假设是错的，相对于现在手机的尺寸，覆铜很难作为一个有效的射频地，所以
手机天线的设计一定要在初始阶段就要考虑电路板的形状。这个导致基于2维无限地的
Method of moment其实不是很有效的仿真，修改后基于多层substrate的greens'
function的MoM软件好像也不是很准确。基于FDTD或者FEM的就有比较好得结果了。
另外，就算作为一般的analog ground或者digital ground，现在复杂电路板的power
plane/bus和ground plane都不能再认为是理想了，大量的power integrity软件就是为
了解决这些plane perforation, parasitic inductance, plane capacitance的问题了
，设计不好，电路通过这些覆铜的互相干扰还是很严重的~
天线,公司等背景吸引眼球而已. 能够起到抛砖引玉的作用,看到... 阅读全帖 |
|
k**l
发帖数: 14 | 11 Our group has an opening in Mountain View, CA. If anyone is interested, I
can help forward your resume to hiring manager if qualified.
Requirements
* M.S. or Ph.D. in physics, electrical engineering, or equivalent (Ph.D.
preferred).
* Solid knowledge of device and/or process physics.
* Deep understanding of semiconductor technology issues.
* TCAD experience is highly desirable.
* Solid understanding of capacitance extraction
* Understanding EDA tools is a plus.
Please send the resume to ray4lin2... 阅读全帖 |
|
s**********l
发帖数: 66 | 12 这个回复相当的有问题啊
1）“输出高频率电平”，这个专业术语我没有听说过。自己定义的？
2）“数据总线电流功率不够”，我明白这个意思，但是一般不这么说，而是说"总线驱
动能力不足"。这一般是由较强的容性负载(capacitive load)导致。 这个驱动能力不
足的问题，如果看过书的话，两分钟就可以判断出来；没学习过的话，可能要搞上一段
时间。我不觉得不看书自己搞是个聪明做法。
3） 顺带问你个PCI规范的问题吧。IBM的工程师在参与写PCI接口并制定规范
的时候，在signalling一节写到 (大意）"一个幅度为1/2 Vdd 的半幅度信号由驱动源
发出后发送到接收端，然后在接收端弹射一次达到信号满幅度，这样一个信号就算传输
完成“。请问这个接口的signaling机制为啥要设计成这样？ |
|
b*******r
发帖数: 1130 | 13 不懂瞎说
假设你有不同size或者厚度的介质，你可以估算他们的电容比
另外假设contact capacitance对于每个电容都是固定的
这样你可以通过测试不同的电容把metal contact的效应去掉吧 |
|
g********S
发帖数: 246 | 14 Please google the following 2 keywords, maybe they will help
1. fast IV capacitance method
2. Time dependent Reflection
a
讨论 |
|
b********d
发帖数: 720 | 15 如果能保证gate leakage and breakdown没有问题，薄了肯定好啊，C大，device容易
turn on啊，low power FET application
所以理论指导寻找leakage和capacitance的平衡点很重要
当然，我的想法还很幼稚的，我随便想想的，还没有想通 |
|
b********d
发帖数: 720 | 16 不是
我的思路是根据film的形成方式推断这种作用力对dielectric的影响（比如那篇paper
里两层界面间的dielectric怎样的，没人解决这个问题），如果我有一个从dipole
moment层面推理出来的合理的capacitance假设，剩下的就是通过实验验证我的假设
所以我就想有没有更多的带入外界作用小的测C的实验手法
如果你把形成dielectric的机理高清楚了，为什么不能理论计算呢？
比如那篇文章里，如果我弄懂了两层之间的dielectric公式，我就完全可以算更多的分
子，不需要一个一个地试，回头你想要多大的C我就可以给你相应的molecule
candidate，不是很好麽？ |
|
l********0
发帖数: 372 | 17 有道理。这就是理论和应用的差异。
其实现在我们更倾向于说permittivity，而不是dielectric constant，因为介电率并
不是一个constant，它随温、湿度，电压，气压等条件变化。dielectric constant只
是一个历史习惯称呼。
以SiN为例，不同条件下得到的只是Si(x)N(y), x，y随制备条件的变化而变化，所得到
的产物的permittivity当然也不同。其实对材料而言，是没有perefect，纯净的。还以
Si3N4为例，如果用PECVD生成，即使你设计了完美前驱物比例，在气象前驱物混合之初
和depostion快结束的不同阶段肯定生成物的defects的种类和数目都不同，其产物的
permittivity就会不同 -- 实际上最终所得产物是由各个permittivity不同的产物层叠
加而成。
想实际测量1-5nm的thin film的capacitance还是有办法的，如果你再有defects的种类
和数量的数据，你就可以建立模型了。如果想模拟纯净材料的permittivity，可以从分
子结构，电负性进行计算，这都有现成的模型。p... 阅读全帖 |
|
m**a
发帖数: 464 | 18 说在一个电梯里用弹簧悬挂一个金属球，问需要什么器材、如何测量球的位置。因为面
试的组是做touch screen的，所以我觉得这个显然就是问电容了。
我只有一个general idea: 只要能求出sphere到floor的capacitance，那就可以反推出
距离d，因为球和地就组成了一个电容。
但是怎么求这个电容呢？需要一个bridge circuit，然后把球和地接进来吗？
这两天我在网上找啊找，找到一个MIT的lab report，是讨论：
“Determine the behavior of a charged particle suspended between the plates
of a parallel plate capacitor as a function of the plate separation and the
separation of the sphere from a plate when there is no potential difference
between the plates.”
就是说两个plates（无电势差）之间放一个带有... 阅读全帖 |
|
g**u
发帖数: 255 | 19 一对stripline的印制板传输线，信号的传输速度应该是c(speed of light)/root(
dielectric constant)，今天看传输线理论，有看到说速度是c/root(L*C), L and C
are unit inductance and capacitance of the transmission line.
彻底糊涂了。狗了一下，没看到任何地方同时讲这两个的，我哪儿弄混了么？望高手不
舍赐教！ |
|
p***o
发帖数: 1252 | 20 Check wikipedia for Capacitance and Inductance, looking for
Pair of parallel wires, high frequency.
Read more on the relation between speed of light, permittivity,
and permeability. |
|
b*****g
发帖数: 2727 | 21 For example:
The C, capacitance per unit length of a coax is: 2*pi*epsilon0*epsilonr/ln(D
/d);
The L, self-inductance per unit length of a coax is: mju0*ln(D/d)/(2*pi);
L*C = epsilon0*epsilonr*mju0
1/root(L*C) = 1/root(epsilon0*mju0)*1/root(epsilonr) = c/root(dielectric
constant). Here c = 1/root(epsilon0*mju0).
|
|
l*****d
发帖数: 508 | 22 【 以下文字转载自 ME 讨论区 】
发信人: lisland (lisland), 信区: ME
标 题: 大家觉得像我这样背景的以后适合干什么？
发信站: BBS 未名空间站 (Sun Oct 18 16:35:55 2015, 美东)
本科学的EE，博士在ME Department做MEMS。之后去了National Lab做了几年精密仪器
的集成、测试和振动分析。平时主要捣鼓laser interferometer, capacitive sensor,
linear stage。同时也做一点简单的机械和MEMS设计，Microfabrication。
绿卡刚拿到。折腾了这么多年，也不知道自己算EE还是ME了。博士学校一般，在学术界
没啥前途。MEMS/半导体貌似形势不太好，不想再回去了。不知道去industry的话应该
找哪方面的。太老，没法转行做码农了。 |
|
s******7
发帖数: 158 | 23
impedance
没你想的这么简单。这个问题和具体的线圈尺寸，铜片尺寸以及两者的距离相关。简单
来说，假设频率不是极高的情况下，铜片靠近线圈相当于加了一个capacitive loading
。这个loading的大小导致整个系统处于感性，容性，或者是刚好在谐振点上。越接近
谐振点源的输出功率越高，损耗越大；越远离谐振点越没有影响。
当频率进一步提高的时候，以上模型不适用。线圈或者铜片自身就可能谐振，分析起来
会很复杂。 |
|
p*********e
发帖数: 203 | 24 One Ph.D. student position is available for Spring 2009 at Dr. Xinyu Zhang's
group, in the Department of Polymer and Fiber Engineering at Auburn
University, Auburn, Alabama, USA.
Current research interests of the group:
• Synthesis and characterization of conducting polymer nanotubes/
nanofibers and composites with noble metals. Investigate their role in
catalysis, capacitive energy and hydrogen storage
• Fundamental research in molecular self assembly using seeding
methods
• F |
|
w********h
发帖数: 12367 | 25 标 题: Carbon Nanotube (2)
发信站: 日月光华 (2002年08月05日08:05:59 星期一), 站内信件
Electrochemical Devices
Because of the high electrochemically accessible surface area of porous nano
tube arrays, combined with their high electronic conductivity and useful mec
hanical properties, these materials are attractive as electrodes for devices
that use electrochemical double-layer charge injection. Examples include "s
upercapacitors," which have giant capacitances in comparison with those of o
rdinary dielectric-based |
|
M********l
发帖数: 181 | 26 一个是Clemson University， 一个是University of Miami，都是PhD offer。
Clemson的老师做的是capacitative energy storage；Miami的老师做的是hydrogen
energy，我将来毕业以后想去工业界找工作。
Clemson的优点是：1）可以四年毕业；2）当地的汽车工业繁荣，就业有优势；
缺点：1）中国AP（但接触下来觉得人很实在）； 2）公立学校
Miami的优点是：1）大城市，热闹，我喜欢热闹；2）女友也拿到了这个学校的offer；
3）中国Professor；4）私立学校
缺点：1）研究生院和专业排名较差，排名上基本找不到他家。 |
|
l*****d
发帖数: 508 | 27 本科学的EE，博士在ME Department做MEMS。之后去了National Lab做了几年精密仪器
的集成、测试和振动分析。平时主要捣鼓laser interferometer, capacitive sensor,
linear stage。同时也做一点简单的机械和MEMS设计，Microfabrication。
绿卡刚拿到。折腾了这么多年，也不知道自己算EE还是ME了。博士学校一般，在学术界
没啥前途。MEMS/半导体貌似形势不太好，不想再回去了。不知道去industry的话应该
找哪方面的。太老，没法转行做码农了。 |
|
p*********e
发帖数: 203 | 28 One Ph.D. student position is available for Spring 2009 in Dr. Xinyu Zhang's
group, at the Department of Polymer and Fiber Engineering, Auburn
University, Auburn, Alabama, USA.
Current research interests of the group:
• Synthesis and characterization of conducting polymer nanotubes/
nanofibers and composites with noble metals. Investigate their role in
catalysis, capacitive energy and hydrogen storage
• Fundamental research in molecular self assembly using seeding
methods
• Fab |
|
m********r
发帖数: 811 | 29 A plane capacitor is filled with a dielectric with dielectric constant e(x)
that depends on the distance x from one of the plates as e(x) = r(x+a)/a,
where a is the distance between the plates; the area of the plates is S.
Find the capacitance C and the charge distribution if the potential
difference between the plates is V.
谁知道怎么做？会不会。 |
|
w*u
发帖数: 2 | 30 In physics system, it is believed that 1/f noise is generated by a continuou
s low activation energy distribution.
Covered the low frequency (low energy) window.
Each activation energy(a 2 level system) relates to a lorenze spectrum(a "step"
function in noise-frequency graph).(something similar to the knee in capacitance
band pass curve )
With continuous steps(flat distribution of activation energy), the slope is
1/f.
As I suggested, there are really a lot about this 1/f noise can be found in
th |
|
p*********e
发帖数: 203 | 31 One Ph.D. student position is available for Spring 2009 at Dr. Xinyu Zhang's
group, in the Department of Polymer and Fiber Engineering at Auburn
University, Auburn, Alabama, USA.
Current research interests of the group:
• Synthesis and characterization of conducting polymer nanotubes/
nanofibers and composites with noble metals. Investigate their role in
catalysis, capacitive energy and hydrogen storage
• Fundamental research in molecular self assembly using seeding
methods
• F |
|
z*******n
发帖数: 1034 | 32 November 10, 2014 8:00 PM
Emil Protalinski
As expected, Microsoft today announced the Microsoft Lumia 535, available in
single-SIM and Dual-SIM versions, the first smartphone from the company
without Nokia branding. Both devices are priced at an estimated 10 ($136)
but that’s before taxes and subsidies; exact figures will naturally vary by
market and operator.
Microsoft says the Lumia 535 and Lumia 535 Dual SIM will begin rolling out
to “key markets” in November. While the company didn’t share a... 阅读全帖 |
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C******g
发帖数: 2930 | 33 Square Enix has announced that Final Fantasy XIV will be launched on Windows
PCs worldwide on September 30 -- well, provided you've obtained the game,
installed it and then clicked on the launch shortcut. This step comes after
you've made a choice between two different versions of the anticipated
MMORPG: a standard edition, which will retail for $49.99, and a $74.99
Collector's Edition.
The latter edition will enable early access to the game on September 22nd ("
subject to initial server capacit |
|
c*******9
发帖数: 1183 | 34 http://www.topgear.com/uk/car-news/new-volkswagen-golf-gti-mark
Some highlights:
*This means the weight drop for the GTI will be about 100kg compared with
now
*We understand that the motor won't go much beyond about 230bhp, but by
switching to the Audi Valvelift system, it will be torquier than today - up
to nearly 260lb ft.
*Also the front wheels of all Golfs will be 40mm further forward than now,
so the car should feel less nose-heavy. Traction will be better, thanks to a
new type of electroni... 阅读全帖 |
|
|
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|
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w*******y
发帖数: 60932 | 39 This is the same phone as the T-mobile Comet but is unlocked. The specs are
not great considering the screen size. It's made by Huawei but was designed
along with Google to develop this phone. Yes, VOICE DIALING with Android 2
.2. The prepaid T-mobile version is $199 right now.
Link:
http://www.newegg.com/Product/Product.aspx?Item=N82E16875606001&cm_re=huawei-_-75-606-001-_-Product
Model
Brand Huawei
Series IDEOS
Model U8150
Color Blue
Form Factor Bar Phones Connectivity
Wireless Radio GSM... 阅读全帖 |
|
w*******y
发帖数: 60932 | 40 Linky: Link:
http://www.meritline.com/male-female-audio-adapter-480---p-3033
Looking for a mid-entry smartphone but not interested in prolonging your
contract? This is a good deal for you!
quote
Palm Pixi Plus for Verizon Wireless, Black
Manufacturer Part # PIXI PLUS
Staying on top of family, work, and fun is a full time job, and Americas
Largest 3G Network has a great new 3G Smartphone to lend a hand. An
organizational mastermind, Palm甈ixi Plus is all about Synergy and
Multitasking. PalmSynergy... 阅读全帖 |
|
|
w*******y
发帖数: 60932 | 42 $75, good Android tablet if youre looking for best of the cheapest web
surfing tablet
Product Specifications:
Internal Storage - 2GB Flash
Internal Memory - 256MB RAM
Headphone Jack - stereo
HDMI output - Yes
External Memory - Micro SD Card (up to 16 MB)
Earphone jack - Yes
Display - 7
resistive (not good as capacitive) touchscreen with High
Resolution TFT(800 X 480 pixels)
DC jack - Yes
Connectivity - Wi-Fi 802.11 b/g
Battery - 1400mah rechargeable lith... 阅读全帖 |
|
w*******y
发帖数: 60932 | 43 Hi.
This is my first post, please go easy on me
I found this deal, for a 4GB Sony Bloggie Touch with 1080p Video recording,
12.8MP Still pictures and 3" capacitive touch screen for $49.99 + Shipping.
Orders over $75 are shipped for free (I added a 2 year replacement plan with
Accidental Damage and Handling for $39.99) and got it shipped for free.
Here's the link:
Link:
https://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId
=10551&storeId=10151&langId=-1&productId=8198552921... 阅读全帖 |
|
w*******y
发帖数: 60932 | 44 Here is the link:
Link:
http://www.amazon.com/gp/product/B0056TO3P8
Compatible with iPad, iPad 2, iPhone, iPod Touch, Motorola Xoom, Samsung
Galaxy Tab, BlackBerry Playbook, HTC EVO View 4G, Dell Streak 7, Viewsonic G
-Tablet, Archos 101 Gen 9 70, ViewPad 7, ASUS Eee Slate, Motorola Droid X,
myTouch 4G, Palm Pre Plus, Samsung Captivate, BlackBerry Storm, Google
Android Tablets, Nook Color and any capacitive touch panel devices.
|
|
w*******y
发帖数: 60932 | 45 Milwaukee 2239-23 M12 Clamp-Gun Clamp Meter/Screwdriver:
http://cgi.ebay.com/Milwaukee-M12-Screwdriver-&-Clamp-Meter-Kit
Milwaukee 2239-23 Specifications:
Jaw Size: 1.57"
Rated: CAT IV 600-Volt and CAT III 1000-Volt
AC/DC Amps: 1000
AC/DC Volts: 1000
Hz: 6 hz to 6 kilohertz
Resistance: 600 kilo-ohms
Capacitance: 0.1 microfarad to 4,000 microfarads
Milwaukee 2239-23 Includes:
(1) M12 Clamp-Gun Clamp Meter
(1) 2401 M12 Screwdriver
(2) Test leads
(2) 12-Volt Lithium-Ion Batter... 阅读全帖 |
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w*******y
发帖数: 60932 | 46 Link:
http://prepaid-phones.t-mobile.com/prepaid-phone/Samsung-Dart-P
I just bought this as a cheap streaming music player for my house, doubles
as a phone. Voice quality is supposed to be good too, which is my #1
criteria for buying a phone. Not much hacking info on it out there yet, I'm
not even sure anyone has rooted it so far, though I doubt that it will be
more than a few weeks before it's rooted.
Note, this is a NEW phone AND WILL NOT BE ABLE TO RECEIVE ANY MORE THAN 2G
DATA SPEEDS EVEN ... 阅读全帖 |
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w*******y
发帖数: 60932 | 47 Sonystyle
Apply Coupon Code: OUTLETMHSTS59
Sony BloggieTouch 4GB HD MP4 Camera - MHS-TS10/S - Silver (Refurbished) - $
59.99 + FS
Technical Details:
Color: Silver
1920x1080 HD MP4 recording: The Bloggie Touch camera lets you record your
favorite moments anytime, anywhere. Using the MP4 format, the Bloggie Touch
shoots video in 1920x1080 high definition, as well as captures 12.8MP still
images
12.8MP still images: Enjoy capturing clear, crisp still photos at 12.8MP
resolution. The high resolutio... 阅读全帖 |
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w*******y
发帖数: 60932 | 48 Hey All,
If I had to pick a consolation 10" tablet I would choose this one for the
price. Viewsonic G Tablet 10" at 209.97 ( no tax in most states)...that is
pretty darn good for the money. Especially for a 10". This is bluetooth
enabled, has the NVIDIA Tegra 2 (really fantastic for web surfing and
watching movies). The nearest thing close to this price is $259 Amazon and
Tiger Direct at 250. Some want over three hundred dollars for this tablet.
There is a good supply of apps for this tablet. He... 阅读全帖 |
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