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snscomputer.com: your #1 online source for electronics [13 Jun 2011|08:39pm]
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changhomin


SNSCOMPUTER.com
is an online e-commerce company that offers many computer hardware, consumer electronics, gaming and communication products that are in stock at competitive prices and ready to be shipped.

SNSCOMPUTER.com has built its business by serving our customers with individualized attention. Our wide selection of products has contributed to our ability to cater to individual consumers as well as many businesses. This has given us recognition from the industry for both loyalty and performance.

Our Pledge:

  • In a conscious effort to maintain the integrity of your data, we will never share your personal information, including your email address, with anyone or any company for any reason (unless required by law).
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Как производят интегральные схемы. [09 Feb 2011|04:14pm]
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rusentu
Видео зарисовки как производят электронные микросхемы.Весь цикл ОТ и ДО.

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Если бы подобную информацию нам рассказывали в институтах было бы СУПЕР.

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Quiet Group, So. . . . [20 Aug 2009|09:38pm]
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peristaltor
Hello to all the lurkers. I've got a project I'd like to prototype, and am looking for someone with an encyclopedic knowledge of parts (or at least moreso than mine) to help me design said prototype.

If this sounds like fun, reply to the linked post. Thanks!
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[25 Jun 2009|11:25pm]
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ruderod
Stop buying Chinese goods! China continues to jail and arrest people who voice any opinion of the big brother Chinese government. Make them hear you! Stop your purchases of anything "Made in China". There are alternatives to chinese made goods! This guy Xiaobo was under house arrest for several month, now the men in black haul him off to jail. If only a few houses on every street stop buying Chinese, the government will get the message that their country will not prosper this way. I noticed the Chinese are trying to edit wikipedia and label Xiaobo as a wacko professor who just wants fame. Nice try.

http://english.rti.org.tw/Content/GetSingleNews.aspx?ContentID=81448&BlockID=31

Taiwan's government has expressed concern over the arrest of a leading Chinese dissident named Liu Xiaobo.

Liu was detained last December just before the publication of a document that he co-authored calling for political change in China. Liu was charged with spreading rumors, defaming the government and inciting subversion. China's official Xinhua News Agency has confirmed his arrest.Read more...Collapse )
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[18 Jan 2009|05:43am]
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ruderod
recycle any old electronics and get a gift card! Note they take ANY electronics mostly, not just Toshiba computers. Thats awesome! Note some older computers and such, you won't get any money for but they will stil take them AND give you a gift card.
http://toshiba.eztradein.com/toshiba/

Now through 1/31/2009 receive a $10 Starbucks Gift Card for recycling an item.

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ET-WEB51 TCP/IP Ethernet Web Control Board [16 Jan 2009|03:35pm]
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review_a_gadget






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Enjoy the Benefits of SKYPE [02 Jan 2009|11:59pm]
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review_a_gadget
<table width="51%" align="center" border="0"><tbody><tr><td>
<div align="center"><img height="100" width="100" alt="" src="http://www.thetechgeek.com/images/product_photos/961237.jpg" /></div><span style="font-size: small"><span>
</span></span></td><td><span style="font-size: small"><span><font face="Arial, Helvetica, sans-serif">Everyone is getting into free
local and International video calling with SKYPE. All you need is a webcam, and Logitech is the best.
</font></span></span><font face="Arial, Helvetica, sans-serif"><a href="http://www.review-a-gadget.com/Webcam.php"><span style="font-size: small"><span>REVIEW THE LATEST WEBCAMS</span></span></a></font><span style="font-size: small"><span style=""><font face="Arial, Helvetica, sans-serif">. </font></span></span></td></tr></tbody></table>
U controller Question X-posted [03 Nov 2008|05:17pm]
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aummaster
We have an older product line we still support that uses the NXP 87C751 non erasable controller. It is a basic 8051 with less memory for those who might not be familiar with it. It is obsolete.

What is happening is the micro is getting messed up some time after it is deployed. I think it is the address bus in the chip. Pages of memory when you read them off the chip are identical. So when the program is read it sees 00-ff correctly but 100-1ff is identical to 00-ff. All pages after the first are identical to the first. That is why I think it is the internal address bus.

We have a relatively unprotected line that goes out of the box (I have been modifying these as they come back with a protective cap and diode) to a wireless receiver. The line in question goes to Pin 8 and is pulled to 5V by a 10 K resistor. The micro is just watching for a transition on this line (high to low). I think that this line is getting a spike on it (probably RF coupling not sure) and damaging the Micro.

Has anyone else seen this kind of behavior before?
Any suggestions for protecting this line other than a 10uf cap and a 6.2v zener diode to ground? That is what I have been putting on them in the past as they trickle in.

This is the fourth failure of this nature we have seen out of about 30-40 systems in the field configured this way.

Thanks in advance for the help.
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Power Supply [15 Aug 2008|03:31pm]
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aummaster
My boss bought a cheap bench top variable supply. It has a ton of ripple in it and it is very noisy. I am trying to find the manufacturer. It has OTE on the front and the model # HY3010E.
I tried putting some capacitance across the output pins. It did not do it. Before I crack it open to try a more permanent fix anyone have any contact info for these guys? I have the owners manual and it does not have any contact (or useful) info (of any kind) in it.

If I crack it open I am going to just load the output with about 1500uF of capacitance. I will use two or three different values in parallel to try and get better filtering overall.

If you have any better suggestions please let me know. Oh buying a good supply is not a real option. The expense would never get approved.

Thanks in advance for any help.
5 comments|post comment
[09 Aug 2008|04:17pm]
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ruderod


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Verizon FIOS install (phone and internet only).
Installer came to the house and immediately asked
"what is behind that wall??"
"Oh, thats the bedroom" I said.
"Oh, well we have to put a battery in there, along that wall" said FIOS installer.
That led to all sorts of questions, until finally I came to the conclusion I didn't want this big box in my bedroom. So I bought a electrical box and had it mounted outside of my house to put it in. Now the question is why is Verizon so cheap, they can't buy a box that is water proof to put the battery in? I don't know. . .the battery is there because the fiber phone won't work in a power outage without it.

I just didn't want this big box in my bedroom, where the thing would start beeping because the battery is dead. When you sign up for FIOS, you agree to replace the battery if it dies after one year.

the grey box is the one I had to go buy (below the WHITE box). Note the 120 receptacle below it, I will probably get conduit and extend the power up into the grey box so i don't use up an outlet. Also will have better waterproof that way.

bigger pics. . .
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[26 Jul 2008|01:00am]
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ruderod
Here are some photos of the Packet8 phone I got today.
Overall rating is excellent. Betty said she heard like an "echo thing" compared to a regular phone. I haven't used it enough to notice, yet. Range seemed decent, though I didn't venture past the front yard. The phone was easy to setup and configure. Some internet connections might require a switch or hub. If you are lucky, your computer would work through the passthrough ethernet, getting NATed IP address. . .as long as your internet modem gives the phone a DHCP ip. If not, you can configure it using the web page and give the device a static IP address, clone your MAC address, some other things.



Only real gripe was the packaging, very wasteful plastic blisterpack that requires a knife to open, plus shipped in a HUGE cardboard box. Yes it all recycles but what a waste of space for shipping.
A plus is a real paper manual of 72 pages for the phone. . .yeah RTFM! And good documentation from Packet8. Also the phone service for packet8 was amazing, quick pickup by a helpful operator to make sure my phone number transfer could get started. FYI when you do the phone transfer, you have to do it AGAIN after you get your phone. If the phone number LNP status does not change after six weeks, call customer service they say! Wow, it can take that long to move a phone number? Hopefully not.

Nerd techie crap: The phone (web interface) can show you stats on each phone call, packets loss and average amount of jitter. I am not sure if the "gap duration" is the time between each SIP packet received?

This was a short phone call while download two large files from internet:

Packets received: 1582 (31640 bytes) Packets sent: 1593 (31860 bytes) Packets lost: 2 (0.13%) Packets discarded: 1 (0.06%) Max. audio burst loss: 2 (packets) Jitter average: 5 ms Jitter maximum: 146 ms Latency minimum: [Unavailable] ms Latency average: [Unavailable] ms Latency maximum: [Unavailable] ms Burst density: 255 (100%) Mean burst duration: 40 ms Gap density: 0 (0%) Mean gap duration: 24240 ms

This was a longer file while not doing anything. Both calls seemed to sound good, maybe a slight distortion on the call while downloading. . but still good audio.

Packets received: 7696 (153920 bytes) Packets sent: 7697 (153940 bytes) Packets lost: 3 (0.04%) Packets discarded: 0 (0%) Max. audio burst loss: 1 (packets) Jitter average: 1 ms Jitter maximum: 33 ms Latency minimum: [Unavailable] ms Latency average: [Unavailable] ms Latency maximum: [Unavailable] ms Burst density: 255 (100%) Mean burst duration: 20 ms Gap density: 0 (0%) Mean gap duration: 44144 ms



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[13 Jul 2008|01:11pm]
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ruderod
The takeover of free and independent TV.

I admit that now as a parent, I have been watching more TV. I watch it over satellite, using DISH network and occasionally watch an HD channel. But my new distraction is from an old Hitachi TV using rabbit ears, setup in my garage. This TV was given to me, I tried to give it away to someone else but settled with having one in my garage, which is sort of nice when you get bored with your other hobbies. Since I live near Los Angeles, I get a good number of spanish TV channels (with the t&a commercials that play constantly), a few of the main stations, I get a PBS station in real well and so I'm pretty happy about that. For occasional channel surfing it works fine. But wait, they keep telling me to get a DTV reciever by 2009 or I won't see anything? What is that all about.

Enter "Digital Broadcast Television". Our fun loving government and broadcaster have tried to get us all to switch to digital television for years now, and they believe next year is the right time. 2009 baby, they say that's when the fun starts, party on!! They say with excitement, it's finally coming. . the government and broadcasting corporations have put lots of effort and teams of people to make this the one event that happens. They say you either get a DTV reciever for that old TV, or you will only get like three channels, if that!

So what's good? Well digital tv, or call it DTV for short, has been around for years. We get it via satellite, and many people already view local news in HighDef over the air. Many broadcasters have been transmitting the new DTV signals for years. . .just not that many people have started using them. I will try to make a list of the good things regarding DTV.
The good:
1. Some of your DTV channels will be in high definition. Well I don't care because my old Hitachi doesn't do HD. If you have a HD TV and reciever, this is good because it is truly something EXTRA you would get for free. . .free HD on some over the air channels.

2. They say this is good for the radio geeks, as they will end up with more radio frequencies to use for other things. . .but what other things? DTV signals can use up less bandwidth than analog TV.

So far, I'm not really seeing the benefit, especially for me as a viewer. Lets get to the bad news.
The bad:
1. You have to buy a digital box to convert your TV, it will only cost $20.00 if you are lucky and get a coupon from the government. Or wait, is this a good since it's only $20.00 ?? But wait, I can't find any converters that cost $60.00. All I see in converters that cost me $140.00. That is $100.00 I have to pay!!

2. A big bad one. . .an estimated 1.8 million people will lose the ability to access over-the-air TV entirely as a result of the digital transition. How is that possible you say? Well, for some reason they are lowering the power of the new DTV signals, so they won't go as far. Yikes. How is this good?
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[19 Jun 2008|07:49pm]
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meltedeyes
Hey all,

I'm looking for a simple circuit that will amplify a pulsing .2V to roughly 9-12V.

I think an op-amp will do it, but I'm not sure.

The application:
I am using an electronic dog collar to trip a latching relay when it get's too close to the transmitter (roughly 6 feet). This is going on a mobile platform so all power is going to be coming from batteries.

The dog collar operates in pulses at roughly 100Hz if memory serves. All I need the amplifier to do is provide enough voltage to trip a latching relay in a short amount of time.

I've managed to dredge up enough 11 year old knowledge to build (and have tested) the rest of the circuit. I just don't remember enough for this initial part.

I've spent some time reading old text books and on Google, but I'm running out of time to get this thing operational.

And no, this is not being attached to any animal.

Thanks.
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FETs and Gate Resistors [27 Mar 2008|09:31am]
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aummaster
We are using a 2n7000 to control a 3-5 V dc signal. It is just being used as a switch.
We are using an ARM processor to control it. I have always heard it is best to put a small resistor (1k or less) between your Micro and your Transistor to protect the Gate.

Some of the 2n7000 have resistors and some do not. The owner wants to remove them on all the FETs and save board space. I think we need to keep them. The design is from before my time here and some of the FETs have resistors as large as 10k between the Gate and Micro but just as many have no Gate resistor.

What is the best design practice for this? Does the ARM put out little enough current that protecting the Gate is not necessary?

Thanks
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ET-WEB51 TCP/IP Ethernet Web Control Board [16 Feb 2008|03:37am]
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review_a_gadget
[ mood | 👁 Image
crazy
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Get a great deal on the ET-WEB51 TCP/IP Ethernet Web Control Board for just USD $79.00. As a value-added bonus get the matching Keil C51/ 8051 port of the uIP v0.9 TCP/IP stack for FREE!.
Buy the ET-WEB51 TCP/IP Ethernet Web Control Board Online Here.

PCB [11 Feb 2008|08:53am]
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aummaster
I am used to either ordering prototype boards from a board house or building on those prototyping boards that have rows of plated thu holes. I want to make a better looking board for a project I am working on but I also do not want to cough up all the cost for 5 or 10 prototype boards when I expect to need one or two.

I was thinking about buying a etching kit (over $150 for the full kit) but they cost more than having boards made.
Is there a cheaper way that I am not familiar with? I can have prototype boards made if I have to.
I saw double sided copper sheets for about $15. If I could etch them myself that would be great.
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Tube Amps Discussion Group [16 Jan 2008|10:46am]
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atillathehung
An amp builder I know has started a Google Discussion Group all about tube guitar amplifiers. He's a pretty laid-back and knowledgable guy who's basically interested in bouncing ideas around. I joined, but he could really use a few more people to jump-start the discussion. Wanna join? Check it out here. 'Cause you can never have too many outlets for talking about amps!
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Building Long Range Acoustic Device [31 Dec 2007|10:10pm]
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kray_zemli
I know this sounds crazy, but I am going to build LRAD clone at home. I've read the "How LRAD works" article. The only idea it brings is the using an array of piezoelectric tweeters.

I've browsed electronic parts shops for piezo buzzers. The best I could find is 100 dBspl/30cm -- with its size 12x12 mm, the stack of those can give up to 135 dBspl, that is still far from 151 dB LRAD is claimed. Besides, those buzzers have very narrow resonance. I know the last one might be solved by using a trumpet. But, if I want a range of 400 Hz - 4 kHz (speech), I need about 1 meter length trumpet, so even making it in labyrinth style would not allow to make device as compact as original LRAD.

Also, this picture that seems to show internals of LRAD, is not like an array of tiny buzzers with trumpets.

Does anyone have an idea how to build LRAD? What tweeters do they use? Does they make their own tweeters or just use conventional ones in overdrive mode? Are they really piezoelectric?

Also, if someone known a community that is good for this question -- please let me know.
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Crystal Questions [20 Dec 2007|03:18pm]
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aummaster
Ok we have a couple of prototype boards. One is misbehaving. We are using an Arm processor with a 12 Mhz Parallel crystal oscillator. The oscillator started up and was running for a few minutes then quit. I am not sure why. I tried replacing the oscillator, the caps (36 pf), and the CPU. None makes a difference. I tried to introduce some extra noise by hanging a clip lead off each leg of the crystal with the other end hanging across the board to pick up noise. I tried putting a 100K resistor across the oscillator. I also tried it with no caps and caps of half the value (15 pf).

When I measure the oscillator sometimes it is at 1v sometimes it is at .1v DC. It almost always looks like it is over damped. It starts to ring but it dies out in a couple of cycles. It will start to ring again but quickly die out.

There is over 3 meg of resistance to ground so I do not think there is a ground short. The same circuit schematic works find on the other prototype board. I am thinking there is a problem with the board and I will next drill out the vias (it is thru hole the boss likes it better for prototyping) and solder directly to the lands for both the oscillator and the caps that connect to the oscillator. I will leave the caps ground connection in place.

Any suggestions before I go that far?
Thanks
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[06 Dec 2007|08:37am]
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ruderod
a note on how our world is effected by the world demand for electronics. They use COLTAN mineral somehow in the LION charging circuits/power switches?

http://www.wrm.org.uy/bulletin/69/Congo.html
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