Reverse Voltage Protection with a P-channel MOSFET
Reverse polarity protection
Everything was working fine for a long time. But suddenly the device is getting slower than usual (e.g. apps react slowly when starting an action -- like the RSS reader takes "ages" to open an article). Also, several apps start crashing: force-closes as well as unexpected restarts. Sometimes this even involves some automatic reboot of the device.  Is there anything I can do, besides doing a factory-reset? Preferably it should work on un-rooted devices.  Remark: not all described problems may occur together, so on one device e.g. there might be no automatic reboot involved. Question remains the same, nonetheless. How can I use function's parameter in it? What are Identity Columns? I was reviewing the  for PostgreSQL and I saw that Pg is likely going to get "identity columns" sometime soon.  I found some mention in  but nothing much  is_identity         yes_or_no         Applies to a feature not available in PostgreSQL identity_generation character_data    Applies to a feature not available in PostgreSQL identity_start      character_data    Applies to a feature not available in PostgreSQL identity_increment  character_data    Applies to a feature not available in PostgreSQL identity_maximum    character_data    Applies to a feature not available in PostgreSQL identity_minimum    character_data    Applies to a feature not available in PostgreSQL identity_cycle      yes_or_no         Applies to a feature not available in PostgreSQL    doesn't say much either     An identity column differs from a primary key in that its values are managed by the server and usually cannot be modified. In many cases an identity column is used as a primary key; however, this is not always the case.   But, I don't see anything else on them. How do identity columns work? Do they provide any new functionality or is this just a standard method to create sequences? Any breakdown of the new feature and how it works? Package pgfplots Error: CRITICAL: shader=interp: got unsupported pdf shading type '0' For the set of data , the following code can't compile showing the error     Package pgfplots Error: CRITICAL: shader=interp: got unsupported pdf   shading type '0'. This may corrupt your pdf!.   \documentclass[border= 5mm]{standalone} \usepackage{pgfplots} \pgfplotsset{compat=newest} \begin{document}     \begin{tikzpicture}     \begin{axis}[unbounded coords=jump, view={70}{40}]     \addplot3 [surf,shader=interp]      table [x index={0}, y index={1}, col sep=tab] {mySurfaceData.txt};     \end{axis}     \end{tikzpicture} \end{document}    So, what went wrong to cause this?  P.S. the original data without NaN is available , where I would like to skip plotting those points of z=1. "How are" or "How is" the wife and kid? How do I install python imaging library (PIL)? How do I install the python imaging library (PIL) on Ubuntu?  I tried doing  sudo apt-get install python-imaging   but now when i run     python selftest.py (a script I got from somewhere on the  website) I get (among other warning messages):  ... *** JPEG support not installed *** ZLIB (PNG/ZIP) support not installed ... *** 1 tests of 57 failed.   Have I somehow messed up the PIL -- how do I fix that?  Is maybe the PIL just fine, but that "selftest.py" is not really the right program for checking to see if PIL is installed properly -- how else can I tell if PIL is installed properly or not?  (I'm using Ubuntu 12.04 LTS "Precise Pangolin").  (What I'm ultimately trying to do is to add a 2D barcode generator to some python code, and all the 2D barcode generators I could find that were written in python all seemed to use the PIL). Oven temperature for multiple ducks? Why did the slaver in Astapor think Daenerys wouldn't do exactly what she did? Spoilers! (do I have to even say that here?)  I recently rewatched the episode of Game of Thrones where Daenerys is in Astapor. She makes the deal with the master slaver guy, where she trades him one of her dragons for 8,000 of his very tough slaves. I immediately thought this was stupid for two reasons:   Why would he think the dragon would immediately obey him rather than her? Maybe he doesn't quite believe the 'Mother of Dragons' lore, but it's still basically a pet at the very least. This one isn't as bad though, as... Why would he possibly think she wouldn't betray him and use her freshly bought slaves to take back her dragon? He just traded her literally all his slaves and he has not been kind to her so far. He has motivation to not go back on the deal -- he's running a business, basically... but she has no reason not to.   I guess you could argue that he was blinded by greed, but I think that would be poor writing -- he's in a vicious trade, I can't imagine he would've survived long thinking so naively.  Does anyone have a good explanation? Gravatar profile image not showing sometimes It seems that with some profiles the Gravatar image is broken. I am not sure if this is an issue with SE or Gravatar, or both, so posting here.  As an example,  shows an error on , which shows a HTTP 500 on Gravatar.  Profile image on SO:        Image on Gravatar:        Switching to the MSE profile of the user, the image is working (but has a different hash).  Is this a bug on the SE side? Can anything be done to make Gravatar fix this?    Update 2016-10-04:  It happened to me again two times today. The last user profile was . Calling the service two or three times fixes the issue. I tried to install Ubuntu 18.10 on my XPS 15 9570 earlier. Everything was working fine until I got to the partition selection part of the installation. That's when the installer crashed and I had to shut down my machine. I think it's because I had my SATA configuration set to RAID ON instead of AHCI, which is now fixed.  Now when I try to run the installer from my bootable USB I get the following error  Failed to open \EFI\BOOT\mmx64.efi - Not Found Failed to load image \EFI\BOOT\mmx64.efi: Not Found Failed to start MokManager: Not Fond Something has gone seriously wrong: import_mok_state() failed   Hoping someone might have some idea as to what is going on Make your own .sty files Sorry to start a subjective question, but want to understand "own.sty" file.  Other than all \usepackage{} what sort of other commands can be added to the makeyourown.sty file.  Can you include \let command, and \newcommands in it.   What sort of precaution / structure newbies should follow. How do I fix these M4 macro errors? I am trying to compile  but when I run ./autogen.sh the script terminates with these errors  Checking for required M4 macros...   libtool.m4 not found   glib-gettext.m4 not found   intltool.m4 not found   pkg.m4 not found   gtk-doc.m4 not found   yelp.m4 not found ***Error***: some autoconf macros required to build mate-desktop   were not found in your aclocal path, or some forbidden   macros were found.  Perhaps you need to adjust your   ACLOCAL_FLAGS?   What do I need to do to get rid of these errors? I tired installing the latest versions of inittool, glib, gtk, yelp, etc... but I still get the macros errors. I am struggling with this question from Halmos's text, please ignore the imperative language.  "Suppose that $L, M$  and $N$ are subspaces of a vector space. Show that the equation    $$L \cap (M + N) = (L \cap M) + (L \cap N)$$   is not necessarily true.  Since each of these subspaces has origin in them, clearly there intersections could not be empty. I wasn't able to formulate an example where this result did n't hold. Any help would be highly appreciated. How do you Set Custom Time in Ubuntu? Editing photo dimensions in large batches If I had the time, I would go through each and every photo to make sure that the dimensions and quality are pixel perfect. However, I'm in a time crunch, and need to make the couple hundred photos that are 4320 x 3240 into 950x630.   now I could- 1. Upload them into WordPress, uses native image reducing components and J query go from there. 2. Go through each and every photo, reduce file size, and proportion and bring it to Yahoo's PNG processing script.  However, maybe I'm missing a choice or alternative workflow that would allow for processing all of these photos in a clear manner without losing quality or perspectives. Any workflow suggestions? If $f^3=\rm id$ then it is identity function Let $f:\mathbb{R}\to \mathbb{R}$ be a continuous function such that $f^3(x)=f\circ f\circ f(x)=x$ for all $x$.  How can I prove $f$ is the identity function? What is Attribute Based Encryption? Geometric proof that a Pythagorean triple has a number divisible by $3$? Can I infer from “If $a,b \in \mathbb{N}$ such that $(a,3)=(b,3)=1$ then $a^2+b^2\neq c^2$ for any $c\in\mathbb{N}$” that any pythagorean triple has a number which is divisible by $3$? If so, how can this relationship be proved geometrically? How to edit Parameters for an Object after it is created? Proof involving absolute value and maximums Given the definition for any real numbers a and b, the max function is   $\max\{a, b\} =  \begin{cases}                                    a \text{ if } a \geq b \\                                    b \text{ if } a &lt; b \\   \end{cases} $  Lemma: for any two real numbers $a\text{ and }b, a \leq \max\{a,b\}$ and $ b \leq \max\{a,b\}$.  Prove that for real numbers, $a, b$, and $x$, if a $\leq x \leq$ b then $|x| \leq \max\{|a|,|b|\}$.  So far, I have  $x \geq 0$ or $x &lt; 0$ by the law of trichotomy  Case 1: $x\geq 0$  $|x| = x$ by the definition of absolute value  and I'm not sure where to go from there. Any hints?