I have device with one PCB with 6 parallel LEDs (30mA and 3.8V forward voltage each). This very small PCB is connected via 2 vires to main PCB where 555 timer is generating PWM signal based on voltage input (potentiometer). Everything is supplied with 5V DC. And now's question:  It's better to add resistor for each LED or lower voltage to 3.8V on main PCB (with voltage divider maybe)?  Also, on LEDs PBC I have space only for 0603 resistors, which power is lower than LEDs power.  Thanks for help :)
Why can't you use a single resistor for a number of LEDs in parallel instead of one each?
How to Backup and Restore Android OS without Rooting Is flair tab working correctly? Is the flair tab working correctly?  It is counting aproximately 3 times more points and over 2 times more bronze badges at the time I'm posting it. How can I reliably get the operating system's name? Say I am logged into a remote system, how can I know what it's running? On most modern Linuxes (Linuces?), you have the lsb_release command:  $ lsb_release -ic     Distributor ID: LinuxMint Codename:       debian   Which as far as I can tell just gives the same info as /etc/lsb-release. What if that file is not present? I seem to recall that the lsb_release command is relatively new so what if I have to get the OS of an older system?  In any case, lsb stands for Linux Standard Base so I am assuming it won't work on non-Linux Unices. As far as I know, there is no way of getting this information from uname so how can I get this on systems that do not use lsb_release? How to pivot rows into columns MySQL 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 Handling mouse events for tool called by button? I have a dockable window with a 2 buttons that call 2 different tools (Draw Marker and Select Features), What i want to happen is when the user clicks on the relevant button on the dockable window and then clicks on the map, a onMouseUp event is called and it runs code i need to run.   Where does the onMouseUp event need to be placed so this can be done? Is $x^x=y$ solvable for $x$? How can I find more music similar to the ones I like? What are the relationship between administrators groups of domain, dev computer and of Sharepoint services? I know-know I can search and read but anyway I would need to ask in order to escape possible typos, personal misunderstandings and to better remember.     I develop on a machine with installed Sharepoint 2010 Sever where I have local groups:     Administrators Description: Administrators have complete and unrestricted access to the computer/domain   WSS_Admin_WPG Description: Members of this group have write access to system resources used by Microsoft SharePoint Foundation      **Does the description of "Administrators" ("computer/domain") imply all privileges of "WSS_Admin_WPG" ?    Does the description of **WSS_Admin_WPG (in part of "system resources used by Microsoft SharePoint Foundation") imply Sharepoint Server?**    The WSS_Admin_WPG group has entries of:     "BUILTIN\Administrators (S-1-5-32-544)" group   and some user domain accounts   Is "BUILTIN\Administrators (S-1-5-32-544)" group the same (alias to?) as "BUILTIN\Administrators" entry I observe among Sharepoint Farm Administrators (through "Central Administration")?       Is the entries of domain accounts excessive (or necessary)     in "WSS_Admin_WPG" if these accounts make part of "Administrators" group?     in "Farm Administrators" if these accounts are part of "BUILTIN\Administrators (S-1-5-32-544)" group?     What are relationship (difference) between "BUILTIN\Administrators" and "Administrators"? Cu has an unpaired electron in 4s, but it is diamagnetic. I thought that it has to be paramagnetic. What am I missing? Full Wi-fi/ethernet signal but no internet I'm really hoping someone here can help me, as I'm getting pretty frustrated with my macbook now. I have a late 2011 model 15" macbook pro running OSX 10.9.5 that refuses to connect to Internet on my home network. I have the same problem whether it's WiFi or through ethernet cable, I have full signal but not getting online. Every other device connects fine; android phones and tablets,xbox one, iPhone and other macbooks, all online and browsing the net. I have had no problems connecting to other networks with my macbook pro before and I just tried at a friend's house to check, with no problems. A little something, that may be a clue to someone: when I open network diagnostic tool, my macbook pro connects for something that seems like a microsecond and it tells me I'm connected to Internet and everything seems fine. My IP is 192.168.0.5 subnet mask 255.255.255.0 and IPv6 is set to automatic. None of the options are checked under the proxies tab. Now I've tried the following, in different order and a number of times, to no avail:   Renewing/turning off&amp;on/inputting manually DHCP.  Restarting/resetting the router and the macbook.  Turning WiFi on/off. Remove &amp; add services (WiFi &amp; ethernet). Checked and copied all network settings from another macbook pro that's connected and online on my network. Ran network diagnostic and assistant tools Duplicated/removed/added location Removed the /Library/Preferences/SystemConfiguration folder. Removed network password from keychain.      I've tried other things too, but can't remember what else right now.  Response from ifconfig en1:  en1: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500              ether 28:cf:da:e6:95:0a              inet6 fe80::2acf:daff:fee6:950a%en1 prefixlen 64 scopeid 0x5               inet 192.168.0.5 netmask 0xffffff00 broadcast 192.168.0.255              nd6 options=1&lt;PERFORMNUD&gt;              media: autoselect               status: active    I'm praying that someone out there has the magic words or the 2-click solution for me, but I would be grateful for a long thorough guidelines to solve it too! &lt;3        Regards Trond Let us say I have added a PPA that has X package that I want but it also has Y package that I do not want to use or receive updates from. How can I, from the same PPA, receive updates for a specific package but deny updates from the same PPA for other packages.  A step by step example would be good since this has happened to me in several PPAs that have a particular package I want but also add a whole bunch of others that I do not yet want to update. BibTeX loses capitals when creating .bbl file In C++, what is a virtual base class? I want to know what a "virtual base class" is and what it means.  Let me show an example:  class Foo { public:     void DoSomething() { /* ... */ } };  class Bar : public virtual Foo { public:     void DoSpecific() { /* ... */ } }; how to solve $\int_{-\infty}^\infty e^{-x^2-x{\tau}} \cdot x\ dx$? Gauss's mean value theorem problem Suppose that  $f(z)$ is analytic and $f(z)\neq0$  on the disc $|z|&lt;1$ .  Show that for $0&lt;r&lt;1$,  $$ \exp\left[\frac{1}{2\pi}\int_{0}^{2\pi}{\log}|f(re^{i\theta})|\,d\theta\right] = |f(0)| $$  Any other theorems needed to solve this problem? I don't have any idea just with "Gauss's MVT"  Thank you in advanced. Android OS without Google Services? I'm making a mini game (bomb squad) and the armor needs to be enchanted. I know that armor can be enchanted through command blocks and that is what I intend to do. I am wondering if it is possible to enchant armor twice in one command block or should I need multiple command blocks as I have done in the past? From everything I've read about quantum mechanics and quantum entanglement phenomena, it's not obvious to me why quantum entanglement is considered to be an active link. That is, it's stated every time that measurement of one particle affects the other.  In my head, there is a less magic explanation: the entangling measurement affects both particles in a way which makes their states identical, though unknown. In this case measuring one particle will reveal information about state of the other, but without a magical instant modification of remote entangled particle.  Obviously, I'm not the only one who had this idea. What are the problems associated with this view, and why is the magic view preferred? Explain $\iint \mathrm dx\,\mathrm dy = \iint r \,\mathrm \,d\alpha\,\mathrm dr$ It is changing the coordinate from one coordinate to another. There is an angle and radius on the right side. What is it? And why?  I got:  $2\,\mathrm dy\,\mathrm dx = r(\cos^2\alpha-\sin^2\alpha)\,\mathrm d\alpha \,\mathrm dr$,  where $x = r \cos(\alpha)$ and $y = r \sin(\alpha)$.  but cannot understand and get the right side. The problem emerged when trying to integrate $\displaystyle \int_0^\infty e^{\frac{-x^2}{n^2}}\,\mathrm dx$ where I tried to change the problem knowing $r^2=x^2+y^2$ but stuck to this part. What is the change in the title called and why is it so? Variance of dot product When reading a proof I came across the following step:  $$\operatorname{Var}(x^Ty) = x^T\operatorname{Var}(y)x$$ $x$ and $y$ are column vectors. How can you derive this?