s**a
发帖数: 1995 | 1 I heard that audio chip Wolfson is used in iPod4/5/5.5 and previous
generations. And the in later generations, they abandoned it because the
size and other concerns. But Wolfson produces better sound.
So I got one new iPod 5. And want to send to redwineaudio to "iMod" it,
basically, to replace the output section of the iPod with high quality Black
Gate NX-Hi-Q capacitors.
Anyone tried it before? |
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D**********s
发帖数: 3139 | 2 sansa
Stereo Headphone Audio Amplifier
• 2x 60mW @ 16Ω driver capacity
• 32 gain steps @ 1.5dB and MUTE
• Click- and pop-less start-up and power down
• Headphone and over-current detection
• Phantom ground eliminates large capacitors |
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G****o
发帖数: 229 | 3 我在听，目前主要是讲如何推箱子
project是做 guitar amp 估计都是重点在做音箱吧
Week 1
Lesson 1: Introduction to wave propagation, simple oscillating systems,
sound pressure, sound waves, the speed of sound, wavelength, frequency and
wavenumber, sound pressure level, and auditory directional cues.
Lesson 2: Electronics fundamentals - charge, current, voltage, resistance,
Ohm’s law, DC circuits, finding currents and voltages in simple circuits
Week 2
Lesson 1: Reflection and absorption of sound, resonances in air columns,
res... 阅读全帖 |
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f*******u
发帖数: 76 | 4 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? |
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c****e
发帖数: 59 | 5 总想把我找工作和面试时的那些常见技术问题总结出来, 给以后的中国同学找类似工作
时一个参考.
前段时间我一直很忙, 没能抽出时间. 今天有空就写了一下. 都是我五次面试时的每次
必问的问题:
1.两级运放中的必考问题:
(1). Bode-plot, Phase-margin and Frequency Compensation in Two-stage Op-Amp
(2). Gain-splitting using miller-capacitor in Frequency compensation
(3). Where is the dominal pole? estimate the magnitude of dominal pole and
other poles if have
(4). If the first stage is telescope or folded-cascode, estimate its max
swing, headroom
(5). When used as unity-gain buffer, es |
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f*****y
发帖数: 444 | 6 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 |
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a*****1
发帖数: 80 | 7 木有，是个5 bits 200 MHz switched capacitor ADC，第一年的课设，现在做的是
8bit 250M ADC，PA，PLL是5GHz和4.5GHz的
今年刚买过On家DFF片，太感谢前辈了！实习要我就很好了
另：“女生做application比做hardcore design好。如果人外向的话”
-这是什么意思？展开讲讲呗 |
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W***n
发帖数: 11530 | 8 Propulsion Engineer
General Atomics • Huntsville, AL
Posted 15 days ago
General Atomics (GA), and its affiliated companies, is one of the world’s
leading resources for high-technology systems development ranging from the
nuclear fuel cycle to remotely piloted aircraft, airborne sensors, and
advanced electric, electronic, wireless and laser technologies.
We recognize and appreciate the value and contributions of individuals with
diverse backgrounds and experiences and welcome all qualified ... 阅读全帖 |
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t*b
发帖数: 850 | 9 http://www.lunainnovations.com/Careers/jobs/Senior_Research_Sci
Senior Research Scientist
Danville, Virginia
Luna Innovations, a NASDAQ-listed public company, develops and manufactures
new-generation products for the healthcare, telecommunications, energy and
defense markets. Our products are used to measure, monitor and improve
critical processes in the markets we serve. Through its disciplined
commercialization business model, Luna has become a recognized leader in
transitioning science to so... 阅读全帖 |
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s**********d
发帖数: 36899 | 10 有的有俩电容，但一般的是一个dual capacitor，就是两个做在一起的。
你网上找一下，有卖给end user的店，十块左右一个。这东西常常十年
八年会坏掉。
干这个的常常比修车还黑。上次我找人recharge freon，两个要$250，
后来找了一个老中还好，一百四。
Long |
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b*********r
发帖数: 302 | 11 说实话，我看了半天，也没觉得他怎么忽悠你了。AC这东西，确实是推荐每年service
一次。service不等于repair, 你一定要东西坏了再叫service也可以。两年前我的
capacitor 坏了，repair 花了250， 是当时的fair price. 所以他给你的价格也不是
很高。我的邻居换了一个新AC，花了 7000，但他的电费确实降了下来。
这些东西如果你都懂还会干，并且很enjoy, 自然最好。省钱还放心。但大多数人都干
不来，或不愿干，我想。那就只有叫professional。professional 有他的费用的，大
家都知道美国的labor 很贵，没办法。
我觉得这是一个life style 的问题， 你不愿为这种maintenance的东西花钱，或觉得
market price 太高不能接受。没觉得他怎么忽悠你了。 |
|
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s**********d
发帖数: 36899 | 13 ： So the moral of the story is: knowledge is money.
这就说我说的，换AC capacitor应该收$2500。
你下次自觉点，不要人家说$250你就给250。
要想到人家的知识是无价的。 |
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s**********d
发帖数: 36899 | 14 engineered 上面一层就是hardwood，看不出区别。
有些地区engineered比较好，因为受湿度温度变化影响小。
自己能不能铺看自己的能力，有的人房子都能自己盖。
有的人空调capacitor坏了花250还挺高兴。 |
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g*****9
发帖数: 4125 | 15 There should be a swith next to it (looks like a light switch)
Your capacitor is going bad, you can replace it very cheap.
If you can not find the wall switch, you can turn it off at the panel (
should be labeled) |
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s**********d
发帖数: 36899 | 16 capacitor坏掉了。如果你们那里有hvac supply store，大约
$10，很好换。否则网上买一个。
找人换大概一百多块。 |
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c********r
发帖数: 122 | 17 多谢各位帮助，希望只是capacitor的毛病。 |
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s**********d
发帖数: 36899 | 18 最常见就是capacitor坏掉了。十块左右一个，如果你能local或网上
买自己换很容易。找人来换一般要100多。 |
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b*********k
发帖数: 335 | 19 I had same problem.
1) 户外 Fan works, but no 热风。户内 fanworks, but no cold 风
2) Compressor seems not working. It seems it works at the start but will not
work later on. when i just start the A/C，the thin line is slightly warm
and thick line is slightly cold . but after few min, no cold or warm feel
from both lines.
3) indoor 出风口 temp is around 79 while room temp is 82F.
4) check Capacitor by eyes, no obvious overburn or damage, 上段和四周没有鼓
起或烧的迹象。
5) the whole set was installed in 2006.
any suggestion |
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R**R
发帖数: 3318 | 20 鼓风机吹出来的都是热风。打开室外压缩机的cover, 发现电容器接头烧掉。
在网上一查，Capacitor 35+5MFD 440VAC 50/60Hz， $30. 马上ordered.
结果等电容器来了之后再汇报。 |
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p**i
发帖数: 688 | 21 幸运!
同样情况发生了, call了个修空调的中国师傅
第一步也是检查capacitor, 结果换了一个还是不work, 仔细一查, 压缩机坏了
这下一千多大洋打水漂了 |
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e********t
发帖数: 397 | 22 俺有一个空调，8年老，六月份请人做过maintenance，freon都正常。周末发现不制冷
了。检查外边，freon pipe 摸上去是室温，不烫手，风扇看上去正常，吹出来的风是
凉风，不像正常工作时是热风。听声音有周期性的noise，大概每隔10-20秒（？）会有
低沉的哼哼声。
昨天去买了个capacitor，换上后还是没有解决问题。估计是不是compressor坏掉了？
有经验的大侠们给说说。 |
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s**********d
发帖数: 36899 | 23
95% compressor capacitor坏掉了。
一般是一个圆柱形的比coke稍细一点。看看是不是鼓起来了。
如果你能找到卖个个人的hvac supply shop，十几块钱。
网上也能买到，可能会稍贵另外得等。
换很容易，不用烙铁，一个螺丝固定，接头是插上的。
其它可能是motor坏了，最小可能是thermostat控制板坏了。 |
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g*****9
发帖数: 4125 | 24 Just to add to 单爷's advice.
If only the fan is bad, it is not 不制冷, it is 制冷 very slow.
不制冷 is caused by bad compressor, 制冷 very slow is caused by the bad fan
(or fan capacitor)
Turn on the ac and touch the thin pipe that goes into your house, is it very
hot? |
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g*****9
发帖数: 4125 | 25 Your capacitor is bad, so both the compressor and fan will not start on
their own, you use the chop stick to start the fan, but the compress itself
did not start.
Touch the thin that go into your house, it should be hot, the thick line
should be cold if the compressor is working. |
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g*****9
发帖数: 4125 | 26 Yes and no.
Just like everything else, they have a life and will require replacement
when reach the end of life (usually leak and can no longer hold)
What is putting more stress on the capacitor is uneven pressure on both side (
caused by very frequent restart), after the compressor stop, pressure will
be uneven, but after a while (5 min maybe), the pressure will become equal,
but if you ask the compressor to start again (shortly after it stopped), it
will put a lot of stress on the compressor a |
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c*****l
发帖数: 631 | 27 how to discharge the capacitor?
I have handeled to office already...gosh...
side (
,
it
buy |
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g*****9
发帖数: 4125 | 28 You can usually touch it with a screw driver (between c and fan and between
c and herm)
A charged capacitor that size can give you a big shock if not discharged
first before handling. |
|
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s**********d
发帖数: 36899 | 30
吧？
compressor那个大盒子上会有一个盖板，卸下几个螺丝就能拿下来
看到capacitor，一般像coke那样稍细一些。看看有没有鼓包（侧面
或者上面接线的地方）。
compressor边上墙上一般有一个拉的闸，或者一个盒子里面有个塑料
把手能拉出来断电。 |
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g*****9
发帖数: 4125 | 31 房子外面那个大箱子 is called condenser, the part you can see 不转了 is the
fan, compressor is below, which you can not see 不转了, but you can hear.
It is possible the capacitor is bad, search for older posts, it has been
discussed here before.
If you are not handy, have a HVAC contractor to take a look.
If your AC is more than 15 years, it might be time to get a new system. |
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g*****9
发帖数: 4125 | 32 Check capacitor, many posts before discussed about it (a few even include
pictures) , you can search. |
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s*i
发帖数: 5025 | 33 上craigslists上找一free的看看？ |
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b*********k
发帖数: 335 | 34 RWKR gezhi89
Can you advice? |
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l*******s
发帖数: 26303 | 35 这种中英文严重混杂的帖子看起来很费劲啊
not |
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b******r
发帖数: 18 | 36 楼主的问题解决了吗？到底是什么原因造成的空调故障？
我家的空调（2004年安装的）貌似和楼主的一样毛病，开始是压缩机里的风扇不转，发
现电容鼓起来了，就换了新的电容，之后风扇转了，但是还是没有冷气出来，能听到
compressor发出的嗡嗡声。请教高手们，这种情况是不是只能是compressor的问题了？
明天准备叫人来看看。 |
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T*U
发帖数: 22634 | 37 没有氟利昂了，找人系统检漏，然后加氟利昂。
出风口温度应该是设定温度-15. |
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T*U
发帖数: 22634 | 38 空调在北方比南方更容易坏，因为经常不用，低压区压力偏高。
跟北方的汽车空调容易坏一个道理。 |
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l****g
发帖数: 476 | 39 我们家的刚刚修完，也是自己去买了新电容回来换上，发现风扇在转，但不制冷。home
warranty的contractor来了后发现conmpressor坏了，紧接着发现motor fan又坏掉了
，于是换了新的compressor 和 motor fan.中间做了freon recovery |
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g*****9
发帖数: 4125 | 40 Either compressor is bad or you have a leak and most refrigerant is gone.
You need to hook up a set of AC guages to make sure. On each gauge, there is
a pressure scale, and multiple temperature scales based on the type of
refrigerant. I am guessing you have R-410A in your system.
not |
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b*********k
发帖数: 335 | 41 gezhi89,
I have an A/C problem.
1) 户外 Fan works, but no 热风。户内 fanworks, but no cold 风
2) Compressor seems not working. It seems it works at the start but will not
work later on. when i just start the A/C，the thin line is slightly warm
and thick line is slightly cold . but after few min, no cold or warm feel
from both lines.
3) indoor 出风口 temp is around 79 while room temp is 82F.
4) check Capacitor by eyes, no obvious overburn or damage, 上段和四周没有鼓
起或烧的迹象。
5) the whole set was installed in 2006.
an |
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|
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m**i
发帖数: 5072 | 44 不知道怎么从compressor那里拉闸断电，找到AC的总电闸，把这个电闸关到off可以吗
？ |
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d********a
发帖数: 9567 | 45 这种东西需要自己换吗？
自信有的时候是要付很高代价的。 |
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|
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f******u
发帖数: 767 | 48 电工叔叔会觉得为十几块钱的买卖跑一趟太不值得，顺手把压缩机也给换了。 |
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c********7
发帖数: 739 | 49 我们刚找电工换了一个。先来检查了一次，然后又顺带把attic fan检查了一下，第二
次来一起修的，一共收了150。确实是个很诚实的人。 |
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d*********1
发帖数: 443 | 50 您是在那儿的呀？我们要波士吨电工。 是波士吨的话能不能推荐一下？ |
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