t**********1
发帖数: 26 | 1 I agree with ghz's comment.
This is the terminating resistor. When a line is long, meaning the cable
length exceeds 1/6 of the electrical length of a rising edge, the cable
needs terminating resistors. Without terminators, reflections may occur
at
either end of long cable(or PCB trace).
For further information, please check Howard Johnson's book, high-speed
digital design, a handbook of black magic, Chapter 6.
undershooting
of
rate.
Even
it
is |
|
u*****t
发帖数: 840 | 2 车内的吹风机只在第4档有风 1,2,3档都没风， google了下，很有可能是blower motor
resistor的问题。
但是在风扇第4档出风的时候，打开车内空调，在出风口也感觉不到冷气。
这样的话空调是不是也有问题呢？ 还是空调只在1,2,3档才制冷？
谢谢回复 |
|
g******u
发帖数: 3060 | 3 www.digikey.com
for normal resistors and caps, Philips and Vishay have the biggest
production lines. |
|
w****j
发帖数: 237 | 4 想测试做的power supply 板子，要求有大概1ohm,60W的DC dummy resistor load, 请
问哪里可以买到？？谢谢 |
|
l***g
发帖数: 1035 | 5 经常见到dsp或者cpld 的 dio 有resistor array 10ohm-50ohm。 记得是和噪声有关。
那位有相关的参考资料么？一般多高速的信号，时钟用的上？ |
|
g******u
发帖数: 3060 | 6 it's just a small low-pass filter. You set it depending on your frequency
and load, even though there is no on-chip resistors you may need to add some
yourself externally. |
|
g******u
发帖数: 3060 | 7 you can call it low pass, current limiting resistor, damper, anything.
串联一个小电阻。 |
|
g******u
发帖数: 3060 | 8 could be by assembly, by touching, contacts, anything.
they can exceed your onchip esd rating as it may not be designed to see sth
more than its rating. that's where you add another resistor.
for example a chip rated for Vcc+0.5V at input side, if the input is a
switch or an inductive source, it can generate way higher than the rated
input voltage, even though the IC has some esd protection, it's not designed
for that.
防止assembly这个外接电阻造成的静电，那怎么就不能消除assembly 其它原件造成的
静电呢？事实上，我很少见到出于ESD的目的，而加外接电阻的... 阅读全帖 |
|
g*z
发帖数: 124 | 9 the resistor is used to kill the ringing, overshooting and undershooting of
high speed digital connection.
please note that here, high speed has nothing to do with the data rate. Even
the data rate is low, if there's sharp rising edge or falling edge, it is
still high speed circuit. |
|
o********s
发帖数: 971 | 10 【 以下文字转载自 Automobile 讨论区 】
发信人: ohbrothers (Gargamel), 信区: Automobile
标 题: 2006 passat blower motor resistor
发信站: BBS 未名空间站 (Sun Nov 20 10:04:32 2011, 美东)
does anybody know the location of it?
many thx |
|
f**d
发帖数: 768 | 11 这是一本计算神经科学的优秀著作，全文拷贝这里（图和公式缺），有兴趣的同学可以
阅读
如需要，我可以分享PDF文件（－－仅供个人学习，无商业用途）
From Computer to Brain
William W. Lytton
From Computer to Brain
Foundations of Computational Neuroscience
Springer
William W. Lytton, M.D.
Associate Professor, State University of New York, Downstato, Brooklyn, NY
Visiting Associate Professor, University of Wisconsin, Madison
Visiting Associate Professor, Polytechnic University, Brooklyn, NY
Staff Neurologist., Kings County Hospital, Brooklyn, NY
In From Computer to Brain: ... 阅读全帖 |
|
D**********s
发帖数: 3139 | 12 音量控制对音质的影响，以前有一篇note写得不错，我找了半天才找到，其实还有用变
压器的方法，不过dac这块最保真的方法就是保持位深和标准输出电平，音量控制交给
前级和功放去管就好了，终究绕不过模拟放大这一关的。
Volume Control Technologies
Newsletter Edition:
July 2009 Issue
With the introduction of Benchmark’s HDR-VC™ (High Dynamic Range
Volume Control), many audio enthusiasts are taking another look at volume
control methods. What are the differences between the different volume
control topologies? Is one sonically superior, and why?
The important qualities to consider with respect to volum... 阅读全帖 |
|
m**********e
发帖数: 12525 | 13 他们都乱说，Nissan Altima 风扇1，2，3档都接blower resistor, 但是第4档
直接与地相接，不通过blower resistor，所以你第4档没事。
你的问题不是blower resistor坏了，电阻不会烧的，是保险丝烧了。把Blower
resistor module拆开来，里面有保险丝，把保险丝换了就行。
电路图：
31脚－－电阻－－＋－电阻－－＋－－电阻－－保险丝－28脚－－－第四档
第一档 30脚 29脚
第二档 第三档
这部分叫blower resistor module,在push control module里面，把调风量的
那个塑料盒拆开来里面就是，组件插座标号M78, 如下图
－－－－－－－－－－－－－
＋－－－－－－－－－－－－＋
30脚 31脚 29脚 28脚
位 |
|
f*****0
发帖数: 489 | 14
it can be done. you can use the 5v (Vcc) to power a resistor string
consisting of a sampling resistor and your 10K pot. the sampling
resistor needs to be much smaller than the pot.
configure the measurement so you take the voltage differential off the
sampling resistor on the high side only. By measuring the signal off the
high side, any ripple in Vcc is a common mode signal to the ADC.
however, you do need to have very precisely matched resistors for high
side measurement. this is less of an i |
|
p****r
发帖数: 766 | 15 这个问题非常常见，如果你的车也有这个问题，不妨看看。
热风和空调的吹风风扇只有最高挡（HI）工作，其他档位都不工作了。
导致这个问题的是控制风扇的一个电阻丝单元（blower motor resistor）坏掉了，这
个问题在Toyota Camry的车非常常见。修理也比较容易，购买一个新的电阻丝单元 （
blower motor resistor），大约在$25左右。这个部件经常会坏掉，所以一般dealer都
会有库存。
这个电阻丝单元 （blower motor resistor）在passenger side，需要打开放东西的
glove box下面的挡板，卸下固定电阻丝单元的两个小螺丝，再装上新的即可。
http://www.masschinese.com/cgi-bin/dwz/a_mas.pl?a=175&id=2073&pg=1 |
|
n********w
发帖数: 285 | 16 Box A contains 50 resistors of which 5 are defective;
Box B contains 100 resistors of which 10 are defective;
Three resistors are taken from one of these Boxes, selected at random.
Find P(A/B) probability that they came from Box A, given all three were
defective. |
|
j*******1
发帖数: 2045 | 17 gold Resistor's value = Resistivity*length/area
Even with DC, standard multimeter cannot read the gold bar's resistor value.The
resistor's value is too small, no matter it is T or G. Or maybe a highend multimeter can tell
If it is long thread, then standard multimeter may tell the differenc. |
|
W***n
发帖数: 11530 | 18 As a circuit designer, I don't think we care'bout packaging. ESR is a
parameter of a capacitor. What the heck is it to do with the selection of a
resistor. ESC?! What that related to a resistor. "Temperature coefficient",
that's strange too. It's not a parameter for selecting a resistor either! |
|
j***j
发帖数: 324 | 19 for most sensing resistors, 'ESL' do have effects on the voltage waveforms,
some companies supply low ESL resistors for some applications.
btw: except some fab techs, normally ESL is proportional to the package of
the resistor, so smaller surface mount Rs are prefered. |
|
f*****0
发帖数: 489 | 20 "另外，如果用电压源和电阻，运放，如何做电流源？"
an opamp's based CCS may not be useable here, due to the high minimum Vdd/
Vss an opamp needs to operate.
if you insist on doing that, you are far better of with a 3-pin voltage
reference, like lm317lz or tl431: a couple of capacitors, plut one resistor
+ your variable resistor, and you have created a voltage source whose output
changes with the variable resistor.
if you have to go down the CCS route, you may explore discrete CCS,
especially cascoded jfets: they are inc |
|
c******s
发帖数: 197 | 21 我也这么想来着，只是没有去验证，昨天已经加了gate resistor 7.8ohm，不知道会怎
么样因为这个也不常发生。烧管子确实是在加大负载后发生的，有overkill的heatsink
，也有d-s的snubber，示波器上观察烧管前电流也是很平稳。管子是fairchild的200v5
2A，烧管子的时候电流大约20A
另外为什么看到凡是2110的片子gate resistor都是22ohm么，至少gate resistor应该和
fet的input capacitance有关吧，我用2110加1ohm的电阻驱动有些大管子，平率50k的时
候门及的脉冲都已经开始爬坡了。
谢谢！ |
|
d****o
发帖数: 1112 | 22 有两个一样的ASIC，core都是1.0V的，每个大概需要电流20A
两个load离得比较远，搞一大块power pour或者专门的power layer不太可行。
原来是一个统一的1.0V，检测一个load下面的1.0V，基本上工作正常。
现在准备每个ASIC都有自己的1.0V power supply.可是为了不影响firmware，还是只能
有一个输入到power monitor.
我准备第一个1.0V V1接一个10k resistor引出来，第二个1.0V V2也接一个10k resist
or接出来，然后这两经过resistors的电压连在一起，接到power monitor哪里去。
理论上讲因为10k resistor很大，不会影响到各自的load，这样，中点，就是power mo
nitor看到的应该是（V1+V2)/2，正好符合我的要求
麻烦各位帮我看看，这样做有什么漏洞吗？
主要是为了节约成本，也不想动firmware，不想用analog switch之类的东西搞。
多谢。 |
|
w****p
发帖数: 90 | 23 发包子１００，
以前问过类似的问题：
有一个圆饼形（如一个硬币）电阻，在通电流的时候有热量产生在电阻内，电阻放在空
气中。如何求电阻中的热量分布。
我的问题主要在于如何定义由电流产生的热量。我是个绝对的ANASYS beginner。我也
在看ANASYS的书，大步分求热量分布的都是在一个已经固定的温度环境中求物体的热量
分布。这个电流产生的热量导致温度变化是随时变化的。
发现这个问题可以用LINK68来解决，可是不会用LINK68,找了好多资料没有怎么用LINK
６８的例子，实在着急。我的论文大概还有一个月就要交了，可是就是这么个小问题解
决不了。
关于LINK６８的问题如下，万分感谢！
The resistor is applied with DC current 3A for half an hour
The dimention of the resistor 1cm diameter cylinder (0.5mm long) and the
resistor is put in an enviroment which is 700 cesius
Resisity 0.5
H |
|
w****p
发帖数: 90 | 24 发包子１００，
以前问过类似的问题：
有一个圆饼形（如一个硬币）电阻，在通电流的时候有热量产生在电阻内，电阻放在空
气中。如何求电阻中的热量分布。
我的问题主要在于如何定义由电流产生的热量。我是个绝对的ANASYS beginner。我也
在看ANASYS的书，大步分求热量分布的都是在一个已经固定的温度环境中求物体的热量
分布。这个电流产生的热量导致温度变化是随时变化的。
发现这个问题可以用LINK68来解决，可是不会用LINK68,找了好多资料没有怎么用LINK
６８的例子，实在着急。我的论文大概还有一个月就要交了，可是就是这么个小问题解
决不了。
关于LINK６８的问题如下，万分感谢！
The resistor is applied with DC current 3A for half an hour
The dimention of the resistor 1cm diameter cylinder (0.5mm long) and the
resistor is put in an enviroment which is 700 cesius
Resisity 0.5
H |
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b*****i
发帖数: 849 | 25 ford 我就不知道了，GM这是常见毛病，都是 blower resistor failure, 网上查一下
很多，我是看了换很麻烦，还要reset airbag就没自己干，如果你要自己干搜一搜网上
，一般这个resistor埋的很深 |
|
b*******1
发帖数: 127 | 26 It is the AC fan. Took it to the mechanics. The fan motor is OK, but the
resistor is broken. Read it from Internet, it is still better to fix it
early. It could be dangerous if driven in slow speed. Need to watch the
temperature closely. Another new car broken on my way to pick up this car
from mechanics. Unlucky day.
Recommended examination: 1) fuse 2) relay 3) resistor 4) fan motor
I saw the mechanics checking 1 and 2 using 电表, much easier than pulling
them one by one.
Thank you all for sugge... 阅读全帖 |
|
m******n
发帖数: 6327 | 27 ☆─────────────────────────────────────☆
april08 (april) 于 (Sun Feb 13 10:50:57 2011, 美东) 提到:
是不是风扇坏了。
看了下网上，可能是fuse, resistor,或者是blower motor.
是这样的吗？
求帮助。
谢谢。
☆─────────────────────────────────────☆
awq (awq) 于 (Sun Feb 13 12:57:04 2011, 美东) 提到:
我的车也是这个问题。最初是只有最大风力才有风，现在最大风力也没了。不过把手放
在出风口还能感觉到一点热气，后窗除雾也work,是啥坏了呢？怎么修?求攻略
☆─────────────────────────────────────☆
lamborbikini (脏乱差) 于 (Sun Feb 13 13:02:40 2011, 美东) 提到:
风扇还转吗
☆─────────────────────────────────────☆
awq (awq) 于 (Sun... 阅读全帖 |
|
|
a****o
发帖数: 6612 | 29 首先是诊断。你可以自己动手，比如测量resistor是不是短路，有没有别的不正常。
resistor一般很便宜，也比较好换，可以DIY。如果是blower motor，可以自己买个二
手的，找人换上。配件价格你可以自己查。换blower motor的人工费，你可以向两三家
店分别估价，找个价格最低的。
还有更简单的可能原因，就是blower motor的保险烧了，打开保险盒检查检查。 |
|
m**********e
发帖数: 12525 | 30 别听三脚猫乱说浪费时间了
你这个100%是blower resistor烧了.换一个就是了
更确切地说,是blower resistor里面的一个thermal fuse烧了.这个fuse一烧,
整个电路完全cut off.这一点跟日车不一样,日车人性化设计,烧了还能用最大
风档继续工作.
你要不缺钱就买个新的,要是缺钱,就去radio shack买个thermal fuse,一块钱,
如果连一块钱也没有,直接用电线把thermal fuse短路就成.
的？ |
|
|
l****g
发帖数: 5080 | 32 本来没注意，但前几天忽然下雨，上车没多久，前窗就开始结雾，幸好在local，赶紧
双闪下路，用纸擦一下才勉强到达目的地，到家仔细检查发现是风扇不转。但发现各个
保险丝都是好的，估计有大麻烦了。
Google真是不错，一下就发现这个不是少数，好像Accord，CRV，甚至Acura等等都有类
似的毛病，症状也类似。原来是控制电机转速的transistor/resistor坏掉了（其实是
MOSFET模块,不过网上流行说是resistor),拆下来量一下，果然是坏了。知道原因，就
好办了。那么零件原厂160刀，ebay有28刀的。怎么选呢，再查一查，原来坏掉的只是
一个过热保护，这个零件0.41刀，邮费估计5刀，可是这个要几天的时间。当地有的零
件都是160刀的组件，再查一下Fry's，原来有类似这个thermal cutoff（115C)卖，才2
刀不到。第二天，买好零件，把新零件焊上去。试一下，发现风扇不调速了，这个不行
。再费一番周折，找到问题了，原来代用的零件外壳没有绝缘，用导热绝缘垫片垫一下
，再试，问题解决了。前后花了4个小时，和送修车铺耗掉的时间接近了。不过节约了
250刀左... 阅读全帖 |
|
u****g
发帖数: 402 | 33 搞了个paper clip把那个resistor短路掉风扇就转了，应该是那个resistor坏了 |
|
f*******u
发帖数: 76 | 34 I have an RS-2001 as well. It sounds OK but not great. I opened it and was
not impressed by its components. Most resistors are tiny 1/16w carbon film
resistors and the capacitors are relatively small. The soldering left much
desired. The output stage is a pair of Darington's for each channel.
Do anybody recommend to mod it a bit? |
|
f*****y
发帖数: 444 | 35 phone interview with hiring manager & hw engineer - 1 hour
1. brief introduction of company
2. resume questions
3. Difference between i2C and SPI bus? CAN bus?
4. what is size of char, char*, void*, int?
5. What debugger tools do you use? Are you familiar with ICE?
6. Node a and b has resistor r1 and node b has resistor r2 to ground.
Node a have Va, what is Vb? why use this circuit? if exchange r2 to a
capacitor, what circuit is this? can this circuit be implemented by software
and how?
7. how d... 阅读全帖 |
|
n********w
发帖数: 285 | 36 selected at random, 每个resistor被选中的概率相等，这样A中resistor被选中的概
率是50/150，第二个是49/149， 第三个是48/148 |
|
l*****a
发帖数: 559 | 37 The only difference is whether the assumption that P(A)=P(B)=50% is valid or
not.
Can anyone tell 'Three resistors are taken from one of these Boxes, selected
at random.', means 'resistors selected at random', or 'boxes selected at
random'? |
|
b*****x
发帖数: 3786 | 38 狗了一下：
Old dimmers did not save electricity. They used resistors to restrict the
flow of electricity to the bulb, but the resistor would just convert all the
extra energy to heat, which was incredibly inefficient and did not actually
use less electricity.
Newer dimmers take advantage of alternating current (AC) power by cutting
off the flow of energy to the bulb for a short time when the current
switches direction. This does save energy because the light is actually
turning on and off rapidly, so... 阅读全帖 |
|
y******0
发帖数: 164 | 39 本人test engineer，在一家小公司工作（40人左右）。
4月3号的那个星期五中午，我和我的manager一起查看设备。这个设备之前出了故障，
然后由一位electric technician更换了几个部件，更换部件以后我和我manager要确认
一下设备的function。当时我用万用表查看一个relay的电压，同时我的manager要按下
一个e-stop的按钮，如果relay工作正常的话，e-stop按钮按下的同时，relay断开，电
压会有变化。结果我manager按下e-stop的时候，relay没有及时断开，导致局部电流过
大，relay旁边的一个resistor瞬间就爆炸了。由于我距离那个resistor比较近，爆炸
产生的火焰瞬间就把我右手手背烧焦了。
当是手非常疼，我的manager马上就开车送我去了公司附近医院A的ER，做了基本的检查
之后，确认没有其他问题，给打了止痛针，就用救护车给我送去附近另一家烧伤科比较
好的医院B （我manager没跟着一起去医院B，他给我送到医院A等我情况稳定以后就回
公司了）。在医院B查看以后确定为second degree ... 阅读全帖 |
|
|
a***y
发帖数: 19743 | 41 ☆─────────────────────────────────────☆
guanjiu (傻钱酒倌) 于 (Thu Jun 10 00:53:14 2010, 美东) 提到:
都是成熟得很的MEMS器件。找个EE，做硬件整合的问问就知道了。
整合到电路板上很trivial.
农场的拖拉机，带autopilot的那种，Gyro都不止一个。 3D Acc.已经dirt cheap了，
gyro稍微贵点，有量也就$5上下的玩艺。
☆─────────────────────────────────────☆
JTUer (莫愁前路无知己) 于 (Thu Jun 10 01:03:04 2010, 美东) 提到:
您估计不是EE的吧。。。
☆─────────────────────────────────────☆
guanjiu (傻钱酒倌) 于 (Thu Jun 10 01:10:46 2010, 美东) 提到:
您判断正确。俺不是EE科班，顶多算了解点皮毛。
不过俺是product manager，多是在商务层面与客户沟通。价格俺也需要借重EE与采... 阅读全帖 |
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f*****0
发帖数: 489 | 42 you have two issues to solve, both are very easy.
a) use an opamp where you pick up the feedback via a current sampling
resistor in the same loop with the load. vs. the traditional topology, you
need just one more resistor.
b) find a high current output opamp. I would look into high speed dsl
drivers. ad815 (preferred in a sip package, not soic), tpa6120/ths6012, etc.
most of those adsl drivers are duo opamps with high slew rates and high
current capabilities.
now, if that's difficult for you (t |
|
s*******y
发帖数: 4173 | 43 resistor value?
resistor will also generate thermal noise.
and |
|
p**********y
发帖数: 13 | 44 then that's a DC signal and you cannot use a current transformer.
you are mostly out of luck, unless you change the way you design the
experiment.
here is an idea for you to think about. assume you can separate the two "
resistors", put one through a diode, and drive them with a power pulse (it
can be either voltage or current, with current being better).
you can then measure the voltage across the wire in both directions. the
lower voltage represents two resistors in parallel and the higher vol |
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h********t
发帖数: 555 | 45 Block 1, you can use a relaxation oscillator. its frequency is depending on
RC. You can switch in/out capacitors digitally. The problem is you need to
trim resistor to take care of process variation, and the resistor needs to
have almost zero temperature coefficient, if you really want a precise
output frequency and also want it stable over temperature. In most design, I
doubt such requirement is really necessary. If you already have an external
clock, you can probably use PLL to do so. it is m |
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q*******n
发帖数: 52 | 46 通常用一个error amplifier,接一个Pmos和resistor divider反馈.
弱弱地问: 常用的amplifier接resistor divider反馈是不是一样?
谢谢. |
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t****1
发帖数: 827 | 47 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 |
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f****3
发帖数: 502 | 48 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 |
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l***g
发帖数: 1035 | 49 this is not called pull-up resistor... this is a current limiting resistor,
which is alright. the value is decided by the current capability of the pin
on the processor. |
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l***g
发帖数: 1035 | 50 this is not called pull-up resistor... this is a current limiting resistor,
which is alright. the value is decided by the current capability of the pin
on the processor. |
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