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  • What type of tape is made to be used in extreme heat (very high temperatures)?

    I'm looking for a very special kind of tape that I can use to hold down a heating resistance chain. The dang Mica that was holding everything together tore, and when I tried to fix it, it just got pulverized into tiny bits and pieces instead. Every time I was trying to insert literally anything that could just barely pierce a tiny hole into it so that I can keep the resistance chain together, the dang thing would just fall apart faster than a wet paper. Although I understand the advantages of using Mica (as it is non-combustible, an insulator as well as a dielectric), I really don't like it. It's giving me a headache and it is extremely sensitive for whatever reason. Any suggestions would be greatly appreciated.

    1 AnswerEngineering2 months ago
  • What is the word used to describe someone who has fallen in love with an individual who had passed away a very long time ago?

    No, "Necrophilia" is NOT the word I'm looking for (before you write your answer). I'm not talking about a sexual desire here, or any form of sexual attraction towards a dead body. I'm talking literally falling in love with an individual that has long passed away (say over 100 years), even when one doesn't know what they look like. I'm trying to find this word, but all Google is giving me is "Necrophilia" which, again, is NOT the word I'm looking for. 

    Does anyone know what this word is? I know it's very strange, but I have come across this question, and I have absolutely no clue what it is called (in ANY of the 5 languages that I know :P). Any help would be greatly appreciated. Thank you :)

    6 AnswersWords & Wordplay2 months ago
  • Music: What is the best music notation software out there with the best sound libraries?

    Just as the question stated, I'm looking for a music notation software that has the best possible sound libraries with it. I have had started with Sibelius in the past, and then migrated to Finale which, in my opinion, had a bit better sound libraries. I am noticing the lack of "real" sound though, and it is very evident in the scores that I've written. So, I'm looking for the best notation software out there that has the best sound libraries, relatively speaking.

    Now, I know that you might mention VSTs, and dedicated software such as Cubase and Magix Music Maker, etc., but these require MIDI and I don't have the money nor the space for that matter to buy one, especially in the current hyperinflation that my country is suffering. A mere BORG MIDI would set be back a whopping 3500$ which is around 3 years worth of salary with the current black market exchange rate (yes it's that bad in my country). So, sticking to software only is what I can pretty much afford. 

    I do know Musescore has a good reputation, and it is free, but I'm not sure about its sound libraries. I've never really tested them. Can you guys give me an input on that too? Feel free to compare it to other software that are not free as well, I don't mind. 

    2 AnswersSoftware4 months ago
  • Which websites allow to preview books?

    I'm interesting in knowing which websites or online shops allow previewing books (random pages) before purchasing them. I know that Amazon and Google books do this, but what other websites are there (I'm asking in case neither Amazon nor Google allow the preview of a particular book for instance). 

    1 AnswerBooks & Authors5 months ago
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    Does anyone know where I can find these books?

    -Atlas of the Developing Rat Brain by George Paxinos

    -A Stereotaxic Atlas of the Developing Rat Brain by Nancy M. Sherwood

    The problem is that I cannot get these books for numerous reasons. The first is although I was able to find them on Amazon on Abebooks, they do NOT deliver to my country, and even if I am able to find a shipping method, it is far too expensive and it requires over 100$ payment, which is of course unacceptable.

    It doesn't stop there. Even if they were able to deliver it to my country, I STILL cannot purchase them because of the economic crisis that my country is currently undergoing. Our corrupt government stole all of our dollars and put them in the Swiss bank, which caused an economic collapse and the dollar value skyrocketed. For this reason, the banks decided to put a maximum of 10-15$ limit PER MONTH on what we can buy, and even that is for Netflix service. 

    Yet another problem is that I am actually looking for a SOFT copy of these books, not hard copies. Either PDF or EPUB. Even if I can just read it online is fine. I checked Internet Archive for it, but unfortunately I couldn't find any of these two books. The key term in these books is "DEVELOPING". I already have the Atlas of neonatal rat brains and Stereotaxic Atlas of the rat brain but not the DEVELOPING rat brain. It's the atlas of the brain of rats when they are growing up.

    Mind you, these books are very old. Red one is from 1970! PLEASE let me know if you are able to find these two books.

    3 AnswersBooks & Authors6 months ago
  • Why isn't my laptop battery working?

    I own a Fujitsu AH532/G21 Lifebook, so over a 7 year old laptop, that I've always been taking good care of, despite rather heavy usage for important work. A couple of years back, I cloned the HDD to SSD and it's been running like a dream ever since (including today!). Software wise, I don't have a single problem. However, hardware wise... well, you already read the title.

    The problem occurred around 3 weeks ago. I turned on my laptop on battery, when it was on my lap, and all of the sudden for no reason whatsoever, it turned back off. Well, I assumed that the battery life was already very short as it is, and maybe the batteries finally died, even though I had the batteries changed only 2 years ago. So, I though, no problem, I'll just change the batteries by carefully soldering a new set. Yesterday, I did exactly that, and worked perfectly. Checked the voltage on the new set and it is 11.6V (even though it says that the battery should be 10.8V). The other set was only 9.6V. These are Li-Ion batteries. 

    Anyway, I did a lot of things that were suggested online, but none worked. I first checked my adaptor, and nothing is wrong. I checked the internal connection (disassembled my computer) and also nothing is wrong there. All cables still fine that connect to the motherboard. I uninstalled and reinstalled the battery driver (AHCI Compliant Battery Control Method) and it didn't work either. I have even updated my BIOS just yesterday, and it still did nothing. 

    1 AnswerLaptops & Notebooks6 months ago
  • Is it OK to have  different voltage sources with the same ground?

    I'm going to have two different voltage sources. One is already a well-rectified and smoothed 12Vdc voltage source, and the other will be 220Vdc rectified but not smoothed voltage source. My question is if it is OK to have the same ground or not. The reason I'm asking is that that the circuit components are interconnected and I need a common ground for everything.

    By the way, the 220Vdc is not smoothed because I have yet to find a capacitor with large enough voltage and capacitance (even in parallel) that is 2-poled in my country (I have 4 poled capacitors but I honestly don't know how to work with them). 

    3 AnswersEngineering7 months ago
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    What are 4-pole capacitors and how to wire them in parallel?

    Hello everyone. I'm currently designing a driver for a 5 HP BLDC motor that runs on 320 VDC. I've created the circuit for it using 6 power MOSFETS (I used six IRF840) and the microcontroller that will give trigger them is an Arduino Uno. Of course, since 3.3V from the Arduino is too low a voltage to trigger the gates, I also used 2N2222 behind each MOSFET to act as a switch and give out a much higher voltage to the gate of the IRF840s. Naturally, I'll be using power diodes too at the end, right before the connection to the motor so that the circuit is protected from any feedback when the power is cut off. 

    The problem that remains is the usage of capacitors. I realize that I'll need large 400V capacitors, and these were the ones provided for me. However, I've never used 4-Pole capacitors before and have no idea how they work. All I know is that the poles are actually connected to the corners of each plate instead of in the middle like regular 2 wire capacitors. 

    I have looked online and came across a couple of circuits that tell me how to wire them, but I can't simply rely on such circuits without understanding what is going on first. So can someone please explain how to connect not two but NUMEROUS 4-pole capacitors in parallel, as well as an explanation of how they exactly differ from 2-pole capacitors. 

    This is the diagram that I saw:

    https://lh3.googleusercontent.com/proxy/UsCZpRN0z3...

    2 AnswersEngineering7 months ago
  • How to rectify very high voltage to get minimum ripple voltage?

    I'm designing a circuit to drive a 5 Ampere 320 V BLDC motor. I had already asked the question before, and I just needed to be sure of the circuit. I'm using the circuit below. 

    https://answers.yahoo.com/question/index?qid=20200...

    Naturally, I'm going to use power diodes to protect the circuit from feedback at the output of the circuit (the input of the motor). Since the minimum voltage required at the gate of the power MOSFETs isn't enough coming from the Arduino Uno Microcontroller, I'm going to use 2N2222 transistors as switches too for the gates that will provide them a 12 Vdc voltage. I ran the simulation and it is actually working fine (ran it on Proteus). 

    However, there are some problems in real life, naturally. I need to rectify the high voltage as I need to convert it from AC to DC. I have a power bridge that can support 25 Amps and 800V, so that's not really a problem. The problem is in the smoothing area. I calculated the ripple voltage desired (which is around 5 V), and saw that I would require a whopping 12000 uF 500V capacitor, which I don't even know where to get honestly. The closest thing I have to that is a much smaller 10 uF capacitors, which are nowhere nearly good enough. 

    There is another issue. The voltage I need is 320 Vdc. Would it be enough to get a 1:1 transformer and feed it 220 VAC, and take the peak of that voltage (at the capacitor level) and reach the nearly desired voltage (~314 Vdc)?

    2 AnswersEngineering7 months ago
  • Did Yahoo! Answers remove the comment section?!?

    Like the question states. I am unable to comment to any of the answers! Is it a bug, or did they purposefully remove our capability to comment on other peoples' answers? 

    7 AnswersYahoo Answers9 months ago
  • Any ideas about Quiet keyboards?

    I'm looking for quiet keyboards, and all I'm getting are LIES, LIES AND MORE LIES on the internet! I'm getting tired of links that are telling me that this keyboard or that keyboard is quiet, bu when I look at the reviews on YouTube and other sites, they are LOUD AF!!! 

    I want something as silent as a laptop's keyboard, if not even more silent. Seriously, those things are really quiet, but I want a keyboard that's for a desktop obviously. So, does anyone have any ideas about brands/models about genuine and legitimate silent keyboards? Please provide me with a list if you have any. Thank you! 

    2 AnswersOther - Hardware10 months ago
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    How to create a circuit to drive a 3 Phase BLDC Motor?

    As the question stated. What I saw online was this, but I couldn't exactly understand why I needed 6 MOSFETs and not 3.

    https://www.digikey.at/de/articles/how-to-power-an...

    The circuit I had created was actually very similar to this. I have 3 IRF840 MOSFETs for the application, because it is a large motor. For this, I have connected an Arduino and programmed it basically to emulate a PWM with each output pin being on at their respective time for 20 ms (since I need 50 Hz as PWM). 

    Now, since IRF840 requires a gate voltage of at least 10V, I'm going to connect low current/low voltage PNP transistors in cascade with each Power MOSFET, operating at 12V. So, basically, Arduino to control PNP transistors to Power MOSFETs. 

    Below you'll see the circuit I found in the website I linked above. Now, here is my question. If I am to control this circuit with an Arduino, what exactly is the frequency that I need to use for each PWM input in the figure? Should it be 10 ms or 20 ms if I am to achieve 50 Hz, because from what I understood, one set of MOSFETs is affecting the North Magnetic pole whilst the other set of MOSFETs is affecting the South Magnetic Pole. Again, I can easily program this, but I just need to make sure. Note that I only need to run the motor on a single speed, so no need to add additional circuitry for dimming. 

    Thank you all for your answers :)

    2 AnswersEngineering10 months ago
  • How to calculate Network throughput based on Bandwidth and Latency? ?

    How does one calculate the throughput of a network (assuming a certain SNR), affected by latency?

    The thing is that in information theory, the formula that I know of is the Channel capacity formula, which has bits per second (bps) as unit, and is defined by:

    C = B Log_2 (1+ SNR). (B: Bandwidth, SNR: Signal-to-Noise Ratio, C: Capacity).

    Is there a formula that includes the latency as well?

    Thank you! 

    1 AnswerComputer Networking10 months ago
  • Does anyone know what this electronic chip is?

    When I opened the laptop that apparently having power trouble, I decided to check the ICs that are responsible to give power throughout the board. I counted 6 of these, and I think a couple are shot. I want to attempt to repair it as I have the necessary tools as well as an automatic desoldering machine that will automatically heat up and remove the soldered area for replacement. 

    The IC (or Power MOSFET I believe) in question is: A1 KND 900201, but I just couldn't find it online for some reason. As for the laptop in question,  it's the ASUS UX31L. For additional details, I have asked the same answer here 4 months ago, but I got no proper/direct answer:

    https://answers.yahoo.com/question/index?qid=20200...

    Taking it to a technician is also out of the question. People here are literally like "Yea, the motherboard is burnt, and nothing can be done. Buy a new laptop". Heck no! I'm not lazy! I'll attempt to repair it at least, but if only I could know the name of that Power MOSFET to order a new one. (At least I'm guessing it's most likely a Power MOSFET).

    3 AnswersLaptops & Notebooks10 months ago
  • How is torque affected when converting from AC to DC?

    I know that torque wise, DC is much stronger than AC. So, I am wondering what would happen if I converted AC to DC and gave power to a DC motor?

    The motor in question is actually a large Servo DC motor, that has 5 hp and runs at 320 V. So, what I'm going to do is convert the Servo Motor into a DC motor, and then put a 10 Amp Step-Up transformer that has 220 V as input and 320 V as output, and then I'm going to use a large Full-wave bridge rectifier (using those large diodes) and of course the corresponding capacitors on the other end (corresponding for the application) to run the motor directly. 

    The thing is that I don't have the drive for the Servo motor, nor does it exist standalone, so I'm forced to go with this for now. My question is: How is torque affected here, and will setting up the bridge directly the way described work? 

    2 AnswersEngineering11 months ago
  • What power transistors are there that support high voltage and adequate current?

    I am looking for particular transistors that have especially high DC voltage handling capability. When I say "high", I mean, at least 350-400 V DC voltage (the application requires 320 V, so naturally, I don't want it to be barely on the level). The current rating is also important. If it can be 1 A each, then that would be great. 500 mA is also fine, because I can use them afterwards in parallel and use load balancing resistors. 

    So, why am I asking this? First, because I have a few applications that could use such particular transistors, so it would be nice to know about them, and second, I want to try and drive a 5 HP 320V motor, a continuous DC servo motor to be exact. Of course, I know that there are dedicated circuits for this type of applications, but due to the specificity of this particular board, and where I live in as a country, they aren't just readily available. So, I wish to try and construct one on my own. Naturally, I know about the PCBs, soldering, etching solutions, etc., so those aren't a problem. 

    Also note that I am intending to use the transistors stated in parallel to be able to increase the current throughput. Now, I noticed the BUL743 transistor, but the thing is that there is a power limitation. From the datasheet, it says that it can handle only about 256 W, but I could be wrong. So, any ideas about transistors, and any inputs on the project itself? Much appreciated :)

    2 AnswersEngineering11 months ago
  • What's causing my mom to have health issues concerning her stomach?

    Hello.

    My mom is have strange issues with her stomach lately it seems. At least, that's what it appears to be. The symptoms appear completely out of random. She feels like she has nausea, and before you know it, she is in the bathroom vomiting. From what she described, it feels like a certain pressure slightly above her belly button, and right below her thoracic cage, kind of like below her heart. 

    Last time we went to the doctor, she didn't have any heart issues. She had a glucose level that was a bit over the limit, but nothing particular to worry about. 

    Another thing I've noticed about her is that it sometimes take her a long time to go poop, like 2-3 days or something, and given the bathroom is within earshot, it sounds like her poop is more of a diarrhea than your regular solid chunks. 

    She just got out of the toilet now (she vomited), and she said that she has a headache as well as an earache. What could she possibly be experiencing? What possible illnesses could she have? We all eat the same food, so if it is food poisoning, it would have been evident by now. But from the looks of it, she's the only one affected. Can you please help me out? Of course I'll take her to the hospital for checkups but I need to know your opinion on what this could be.

    Thank you

    3 AnswersOther - Diseases12 months ago
  • Why are there such weak protections for PDF files? ?

    As the question stated. I've tried numerous PDF locks, and every time I go to this site to make sure it is secure, it always gets unlocked! All I want is the PDF file to be protected against editing and copying. I don't mind it being printed though. So, I set up a password to restrict access to the file, and save it. Later on, I go to this site and see if it unlocks it. Lo and behold, it does! 

    Does anyone know how to properly secure a PDF file such that when it is uploaded online, it doesn't get unlocked? 

    I can't share the site name as it may break the rules, but it is rather easy to find. Just Google "PDF Unlock" and see for yourselves. I just want it protected from being copied, that's all. (By copy, I mean opening the file and copying its contents of course), not copying the file itself. 

    1 AnswerSoftware1 year ago
  • What is the difference exactly between the 3D-NAND (or V-NAND) architecture TLC and the regular non-planar MLC?

    I really can't tell the difference exactly, because stupid Google always compares 3D-NAND TLC vs Planar NAND MLC. 

    The only difference I found was when I went to compare two of such SSDs on an online benchmark, and it was slightly in favor of the 3D-NAND TLC SSD.

    The SSDs in question were:

    Samsung 860 EVO vs Kingston HyperX Savage.

    For 5 years now, I've used the HyperX Savage (250 Gebibytes, which translates to the 232 Gigabytes. It's actually 222 on my drive now, but that's a technicality), and the performance never disappointed me. The only issue I have is with the storage, which is slowly becoming more limited. Of course I'm planning to do a clone and migrate, but I just want to know what exactly is the difference between the aforementioned architectures (I mean, what EXACTLY is the difference, and how it affects their longevity).

    Thank you! 

    1 AnswerOther - Hardware1 year ago
  • How to mount a camera on a microscope?

    The microscope in question is an Olympus CH30. I noticed that there are some cameras out there that can be mounted on such microscopes, and that they are placed on the ocular lenses (the eyepieces from which an individual observes everything). The thing is that this is rather new to me and I don't want to mess it up with an incompatible piece. Does anyone know an inexpensive camera (c-camera or maybe u-camera) that can be mounted on the aforementioned microscope? The budget is around 100$ and it will most likely be delivered from a site like Aliexpress. Any help/suggestions about camera types (along with links to them) are greatly appreciated. Thank you! 

    2 AnswersCameras1 year ago