I'm working on a small project which involves current measurement.  I'm using R10 to measure Voltage drop (100 mV) when 10 mA current goes through it.  Next I'm amplifing that signal around 37 times using an op-amp (LM358N) which is powered using 0-5 VDC and works as differential amplifier. There should be 3.73 V on the output BUT...  My problem is:  The op-amp is completely ignoring the inputs and it still outputs a value around VCC minus 1.2 V.  Making a symmetrical power supply does not help. I checked everything about 100 times and can't find any solution... If anybody of you know how to help me I'd be grateful.
I've built a current sense differential amplifier that measures the voltage across a 1 Ohm resistor, to give me a reading for the current through it.  I've connected it as follows, all resistors are matched 10k to give a gain of 1:    (Image source: )  I am powering it from a single rail 12 volt source. The problem is even though this is a rail to rail opamp (Output Low swing from 5-20mV) I'm getting a constant error of 0.62V and it seems the opamp is not able to go below this value.   I have tried to resolve this by connected Vout to ground using a 10k resistor, but that makes no difference whatsoever.  I tried it with dual supply configuration (+8V, -8V) and that seems to resolve the issue. However I want to run this off a single supply rail, so this is not a viable option.  How can I resolve this? I'm trying to measure the voltage drop across a 1 ohm resistor to give me a reading for current through the circuit (0-1V represents 0-1 A) so I can set up a current limit. A better way (or practice) to doing this is also welcomed. The initial (but not ideal) fix I can think of, is to offset the readings by a few volts?  Edit:  Changed R1-R4 from 10k to 100k and I'm down to about 30-50mV!
Infinite-Scroll Plugin and Jetpack Infinite Scroll Plugin - Adding to "Thoughts" Theme How do I enable infinite scroll (either with the infinite-scroll plugin OR the built in infinite scroll jetpack) on the "Thoughts" Wordpress theme?  I'm a total noob at editing this stuff so if you are kind enough to help please keep it very simple as if I do not know anything. Alert on edit after a downvote I wonder if it would be possible to extend the current notification system.   Namely, if I downvote a question and that thing had an edit, I'd be happy to see that in my inbox. As possibly the cause for downvote was cleaned up and it should be undone. I am having trouble with the following problem.      Let $R$ be an integral domain, and let $a \in R$ be a non-zero element. Let $D = \{1, a, a^2, ...\}$. I need to show that $R_D \cong R[x]/(ax-1)$.    I just want a hint.  Basically, I've been looking for a surjective homomorphism from $R[x]$ to $R_D$, but everything I've tried has failed. I think the fact that $f(a)$ is a unit, where $f$ is our mapping, is relevant, but I'm not sure. Thanks I was wondering how one can construct a Borel set that doesn't have full measure on any interval of the real line but does have positive measure everywhere.   To be precise, if $\mu$ denotes Lebesgue measure, how would one construct a Borel set $A \subset \mathbb{R}$ such that $$0 &lt; \mu(A \cap I) &lt; \mu(I)$$ for every interval $I$ in $\mathbb{R}$?   Moreover, would such a set necessarily have to contain infinite measure? I have a directory which contains numbered image files, something like this:  01.png 02.png 03.png 03.svg 04.png 05.png 06.jpg 07.png 08.png 09.png 09.svg 10.png   Sometimes there may be multiple versions of a file in different formats (eg. a png and svg version of the 03 and 09 files above) but the numbers are otherwise consecutive.  Typically there are 40-80 such files in each directory.  The numbers correspond to the order these images appear in a manuscript (a Word document, but that's not important).  There is no other way to determine the order of the images.  If I add a new image to the manuscript I need to place a copy of the image in this directory with the correct numbering.  So if the new image is the fifth in the manuscript I need to rename the files in the directory to this in order to make room for it:  01.png 02.png 03.png 03.svg 04.png 06.png 07.jpg 08.png 09.png 10.png 10.svg 11.png   What is the most straightforward way from the command line, or from a script or macro to renumber all the files starting at a certain number?  I have a standard Fedora Linux install using bash. What does [t] and [ht] mean? I would appreciate if someone could tell me difference between [t] and [ht] in the following example? I don't see a difference in the output pdf file.  \begin{figure}[ht] ... \end{figure}   and  \begin{figure}[t] ... \end{figure} Been looking to pivot rows (progress_check) into columns check 1, check 2 etc... No sum or totals required, just to display the results hopefully... Can anyone help, Thanks Ad I'm training a neural network for regression. The input vector consists of $140$ entries.   For each feature vector entry, I calculate both min and max over the training set. The difference max-min of some entries are smaller than 1e-5. I understand I can normalize such feature entries by say MinMaxScalar. However, if the difference max-min is this small, can I discard such entries since they seem to be so insensitive? Curious about text alignment on websites. For a blog, for example, is it better to have left-aligned or justified text? I like the look of justified text but I'm not sure if there's any downsides to it. How to select a clustering method? How to validate a cluster solution (to warrant the method choice)? One of the biggest issue with cluster analysis is that we may happen to have to derive different conclusion when base on different clustering methods used  (including different linkage methods in hierarchical clustering).  I would like to know your opinion on this - which method will you select, and how. One might say "the best method of clustering is which gives you the right answer"; but I may question in response that cluster analysis is supposed to be an unsupervised technique - so how do I know which method or linkage is the right answer?  In general: is a clustering alone robust enough to rely on? Or we need a second method and get a shared result to be based on both?  My question is not only about possible ways to validate / evaluate clustering performance, but is broader - on what basis do we select/prefer one clustering method/algorithm over another one. Also, is there common warnings that we should look around when we are selecting a method to cluster our data?  I know that it is very general question and very difficult to answer. I only would like to know if you have any comment or any advise or any suggestion for me to learn more about this. Propose a privilege to sit in the 500 reputation mark Bash while read loop breaking early I've been banging my head against for wall for a while with this one.  I want to SSH into a set of machines and check whether they are available (accepting connections and not being used). I have created a small script, tssh, which does just that:  #!/bin/bash  host=$1 timeout=${2:-1}  ssh -qo "ConnectTimeout $timeout" $host "[ \`who | cut -f1 | wc -l \` -eq 0 ] &amp;&amp; exit 0 || exit 1"   This script works correctly. Returning 255 if there was a connection problem, 1 if the machine is busy and 0 if everything is good. If anyone knows a better way to do this please let me know.  So next I try and call tssh on my set of machines using a while read loop, and this is where it all goes wrong. The loop exits as soon as tssh returns 0 and never completes the full set.   while read nu ; do tssh "MYBOXES$nu" ; done &lt; &lt;(ruby -e '(0..20).each { |i| puts i }')   At first I thought this was a subshell problem but apparently not. Any help, along with comments on style/content, would be much appreciated! I know I'm going to kick myself when I find out why... How do I install and manage GNOME Shell extensions? How do I install GNOME Shell extensions?  Is it possible to update, remove and manage the extensions? Is there a platform-agnostic and filesystem-agnostic method to obtain the full path of the directory from where a program is running using C/C++? Not to be confused with the current working directory. (Please don't suggest libraries unless they're standard ones like clib or STL.)  (If there's no platform/filesystem-agnostic method, suggestions that work in Windows and Linux for specific filesystems are welcome too.) How can I install more recent versions of software than what Debian provides? I ran into the "mysterious"  \pdfendlink ended up in different nesting level than \pdfstartlink   error.  According to , "this happens when hyperref is used under pdftex and a citation splits across a page boundary".  The given solution is to manual fix the citation to not split across the page boundary.  However, this workaround isn't feasible for me, as the documents are automatically generated on a server with no user interaction.  Is there any solution to the problem known, perhaps an experimental hyperref action or a patch to pdftex?  (Probably, one could use luatex to solve the problem, but for other reasons, luatex is not an option in this project.)  MWE:  \documentclass[%draft               ]{article} \usepackage{hyperref} \setlength{\textwidth}{3cm} \setlength{\textheight}{3cm}  \begin{document} Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna \href{http://www.tug.org/errors}{aliquyam erat, sed diam voluptua.} \end{document} I'm new to the ICS os, coming from Gingerbread from another phone. The phone's quite nice and fast when I first used it, but just this morning it started exhibiting weird actions. Camera360 doesn't open up automatically when I click it, the Camera closes for no reason, Pocket restarts when an article has an image, and TTPod resets the song to the previous song on my widget in the middle of a new song I'm playing.  I checked out the ram, and and was surprised to see 500+ mb used, 0 mb available. I looked at the list of programs and I see the usual culprits like Facebook, but the ram they're using doesn't add up to 500+ mb. Yeah, I know that the whole ram indicated isn't usable by the apps, but I don't think I've done anything to warrant the 0 mb. I close my apps. There are times when there's free 4 to 5 mb, but I think that too shouldn't be the case. I tried installing Advance Task Killer, it listed less than 10 apps, killed it, still the ram is what it is above.   I did a reboot, and now it reads 300+ mb usage, 200 something free.   What can I do? How do I ensure an app's closed on ICS? I installed GoLaucher because it has a handy task killer and I can see the ram freed in an instant, but I would like to know if there's a better way to handle the RAM. Is the graviton hypothetical? Recursivly Deleted Root Directory I recursively deleted the contents of my root directory with sudo privileges. My display reset, and windowing stopped working. I could no longer run non-buitin commands. Most of my directories (including the home directory disappeared).  What I meant to run:  sudo rm ./* -rf   What I believe I ran:  sudo rm /* -rf   I understand how this command works (see ).  I'm trying to get a better sense of how much (and what parts) of the original files and directory-structure physically remains on the hard-drive.  How much of these "remains" are recoverable? E.g is it possible to use data recovery software like TestDisk/PhotoRec to recover the full home dir itself? What about config files? In my resume, I'm describing several projects I've worked on in the past. Most of them were done in teamwork. What is the best way to say this?  Examples:  Together with XY, I built ... OR  In collaboration with XY, I built ... OR  XY and I built ...  Are the first two examples grammatically correct? I'm unsure since first I state that something has been done in collaboration with a second person, but then I use "I built ...".