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    Max Tolerance stack-up

    Hi, I've been reading about stacking up tolerances. It's the first time in working with them. I understand the gist of it and I've seen a few simple examples however when I move onto my project I keep getting lost as I dont know what and where do they stack and if I should just add them up or...
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    Solidworks thermal simulation: is this logical?

    I just ran 2 simulations on Solidworks, same assembly, same initial conditions on all pieces, pretty much I "Cloned" the thermal study and just changed one piece So, from the assembly above you can see the materials for most pieces, the 2 grey pieces in the center are 2 aluminum plates with a...
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    Thermal Conductivity of Springs

    I have a question that I've been debating with some co-workers. We are using conical springs (tapered) that most of the time in our application fully compress once engaged. We are measuring minute changes in temperature and I was wondering if a spring diffuses more heat compressed or relaxed...
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    Maximizing insulation (conduction, convection and radiation)

    Hi, Its been a while since I had my thermal heat transfer classes and Im a little skeptical on what I remember. Im trying to insulate a copper block, the sides are covered by an insulating material which has a low thermal conductivity (they are touching). Howver there is a surface on the top...
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    Increasing Flow rate through system

    Hi, I'm building an experimental set-up for some heat exchanger I'm trying to analyze, I want to maximize the flow through this little piece. I have a stable temperature bath, (see picture) that has an evacuation valve on the bottom. I only took introduction to Fluid Dynamics (found it amazing...
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    Small Machined springs

    Hi, I usually buy off-the-shelf springs, however I am working on a design that requires some very specific features on each side of the spring (if possible), however this is a very small device, (its a probe). Anyways, I was thinking of getting a machined screw, as I've seen some very good...
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    Designing with Thermal expansion in mind

    Hi, Im trying to design a tubular probe thats made of stainless steel (304), from what I've read it has a Thermal expansion coefficient of around 9.6 x10^-6 in/in/F give or take on the quality. I want to fill this tube halfway with an Epoxy, however from what I've read this epoxy has a thermal...
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    How to read lots of inputs

    Hi, Im working on a project that could potentially do 2 of the following. I am a mechanical Engineer and I dont know much about electrical engineering, bu talking to a friend of mine who is still studying EE, he gave me his input which I felt was not the best option, I hope you guys can help me...
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    Logical Channel detection

    Hi, I am designing a PCB with multiple 2-pos DF13 connectors in it (Like 50+). at the end of the board there is a 10 pos. cable. My intent is that the user (me) connects up to 9 channels in any position I like (I have 50 possible choices). However, this board is connected to another PCB that...
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    Pin-screen Matrix feedback

    Hi, This is kind of a hobbyist project or something along those lines. I am trying to build a pin-screen Similar to that, or with whatever conifguration of pins. But I want it to provide electrical feedback so that I can map out where each pin is on a Z-position (their X-Y coordinates are...
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    Torque required by motor

    Hi, I am working on a project that needs some rotation around a central axis. I was looking over at some Servos but I dont know how to calculate the torque required by the servo. I was thinking of doing a simple free body diagram, but as I was drawing it I realized the forces are on the Z axis...
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    Weird PCB stuff

    Hi, I recently designed a PCB in EAGLE, and I got it manufactured and I had all the pieces Sufrace Mounted on it, put it in the oven, everything seems fine and dandy, but I already killed 3 LEDs because of some weird thing going on. I have 5 different LEDs conneced to my circuit, the leds run...
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    From dual to single supply op amp circuit

    Hi, I was just curious, I am no EE, I am an ME and I am trying to make something smaller if you have read my other posts you might know whats it all about, anyways I've been reading a lot about single supply op amps and thats probably the best choice to reduce the amount of power my circuit will...
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    How to not-fry a component

    So I am looking at my spec sheets, I am running most of my boards on 5V (Arduino) There are however 5 LEDs that say can have a maximum FV of 1.5V, so Im pretty sure they will fry if I run the 5V through them, there are also 5 Photodiodes that have a 1.3 maximum FV, so they will fry as well...
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    Schematic of Batteries

    Hi, I am working on a PCB design and the mock-up prototype is now done, thanks for all your help by the way! now its time to get it mobile. I am trying to add a battery (CR2032) to the design of the PCB, the thing is that I have my voltage regulator set up as so...
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    Voltage Regulator,

    Hi, Thank you for all the help you've been providing, here I go again with another Electrical question: I am designing a PCB and I need a voltage regulator similar to this: http://img191.imageshack.us/img191/6499/n7p3.png [Broken] but I dont want to use the LM7805 and the LM7905. I am...
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    Current Mirrors, help?

    Hi, Im working on a design and I am trying to re-work the horrible schematics left by a previous mechanical engineer, I am trying to make a current mirror that will mirror a reference current across 5 LEDs, AFAIK from my little knowledge in Electrical engineering (I am a Mechanical Engineer)...
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    Powder Injection Molding, Binders

    Hi, I was just curious, I needed verification, I am reading up on PIM process and I see they use "binders" to keep the shape of the powders before sintering, anyways as I've been reading the binder consists of a surfactant, a filler and a backbone, I was just curious as to what ratios are there...
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    Project, How to find chips?

    Hi, Im a Mechanical Engineer and I really love the field of mechatronics so I got myself a nice team and we're currently working on a project that requires me to redesign a PCB, I have the circuit schematics and the original PCB, but I have little to no experience with actually designing them...
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    Furnace-Belt Heat transfer

    Hi, I need help tackling this problem and I wanted help since I feel lost. I have a probe running through a belt-furnace that has multiple stages for heating, I know the temperature of the oven at any given time (in minutes), the oven takes 8 hours and the Temperature profile looks like this...
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    Transposing a line with known references

    Hi, I have a question for a desing I am working on. I want to model it in excel and I am having a hard time finding out how to transpose some lines: Let Bar B's position and dimensions be known, and I want bar B to be set in 3 positions, I can however apply joints to anyplace near or at bar...
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    Modeling oscilations in Excel

    Homework Statement You have a car going over a speed bump, you need to model the oscillation of the car using excel only (no matlab or other software) Simple Schematics: |Mass of car| | | Spring Damper | | \...
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    Using Ashby's Tables

    Hi, I am trying to understand how to use Ashby's tables, I have the book and the problems are just too ambiguous and I was wondering if anyone can help me understand this: On whatever table, I understand you have to follow a certain sloped line that contains the features you want in your...
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    What happened to Ohm's law?

    Earlier I asked for help about a high voltage power supply, and I was told not to worry too much about 20k volts because they have a very low current I was left thinking about that say whatever circuit that ends in an inductor and generates that voltage of 20k volts. and I was told that the...
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    About: Magnetic force

    Hi, I am trying to play around with magnets on my free time, I ordered some neodyum magnets and I've been thinking of making my own electromagnets, I had some of questions and I was hoping someone here mmight help me: 1. About magnetic force: AFAIK magnetic force is perpendicula to the...
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    About: Wires and Lifters

    Hi, I am currently working on a personal project, I am trying to build a lifter (ionocraft) According to the book my HV PSU. will give around 25 - 30 kV. I already got all the parts for the circuit, I just have a couple of questions about wires: how do I choose a wire? should I use...
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    Pressure problems

    This is from my Fluids class, Im assuming it should be under Advanced physics? Homework Statement A- The pressure in an automobile tire depends on the temperature of the air in the tire. When the air temperature is 25C the pressure gage reads 210 kPa. If the volume of the tire is 0.025...
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    Relative Velocity and angular velocity

    Homework Statement Knowing that at the instant shown rod AB has a constant angular velocity (w = 15 rad/s) counterclockwise (+k) determine (a) the angular acceleration of rod DE (b) the acceleration of point D Homework Equations (w = omega) VB = VA + VB/A VB/A=w X r aB = aA + a X r...
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    General Plane Motion

    Homework Statement The teacher provided the solutions already. http://www.swccd.edu/~lzinola/engr251/eightedition/ch15/ch15001.pdf Page 2 Problem 19) the two wheels and a belt Homework Equations v = (omega) X r a = (alpha) X r + (omega) X { (omega X r) } The Attempt at a...
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    Aerospace Engineering

    Im going to a science fair to promote Aerospace Engineering. Me and my team are doing a project that helps visualize vortices (throught food coloring and water currents. . .pretty usual) the main point is to talk about delta wings. Im going to specify in delta wings at super sonic speeds and...
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