Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
g

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"(?<code1><a href=\"\/questions\/\d+.+?\">)(?<code2>.+)(?<code3><\/a)" test_str = ("<!DOCTYPE html>\n" "<html>\n" "<head>\n\n" " <title>Newest Questions - Page 2 - Electrical Engineering Stack Exchange</title>\n" " <link rel=\"shortcut icon\" href=\"//cdn.sstatic.net/electronics/img/favicon.ico\">\n" " <link rel=\"apple-touch-icon image_src\" href=\"//cdn.sstatic.net/electronics/img/apple-touch-icon.png\">\n" " <link rel=\"search\" type=\"application/opensearchdescription+xml\" title=\"Electrical Engineering Stack Exchange\" href=\"/opensearch.xml\">\n\n" " <script type=\"text/javascript\" src=\"//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js\"></script>\n" " <script type=\"text/javascript\" src=\"//cdn.sstatic.net/js/stub.js?v=5d233283ca8d\"></script>\n" " <link rel=\"stylesheet\" type=\"text/css\" href=\"//cdn.sstatic.net/electronics/all.css?v=672ddec9ce04\">\n\n\n" " <script type=\"text/x-mathjax-config\">\n" " MathJax.Hub.Config({\"HTML-CSS\": { preferredFont: \"TeX\", availableFonts: [\"STIX\",\"TeX\"], linebreaks: { automatic:true }, EqnChunk: (MathJax.Hub.Browser.isMobile ? 10 : 50) },\n" " tex2jax: { inlineMath: [ [\"\\\\$\", \"\\\\$\"] ], displayMath: [ [\"$$\",\"$$\"], [\"\\\\[\", \"\\\\]\"] ], processEscapes: true, ignoreClass: \"tex2jax_ignore|dno\" },\n" " TeX: { noUndefined: { attributes: { mathcolor: \"red\", mathbackground: \"#FFEEEE\", mathsize: \"90%\" } }, Macros: { href: \"{}\" } },\n" " messageStyle: \"none\"\n" " });\n" " </script>\n" " <script type=\"text/javascript\" src=\"http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML\"></script>\n\n" " <script type=\"text/javascript\">\n" " StackExchange.ready(function () {\n" " StackExchange.realtime.init('sockets.ny.stackexchange.com');\n" " StackExchange.realtime.subscribeToInboxNotifications();\n" " StackExchange.realtime.subscribeToReputationNotifications('135');\n" " });\n" " </script>\n" " <script type=\"text/javascript\">\n" " StackExchange.init({\"stackAuthUrl\":\"https://stackauth.com\",\"serverTime\":1377686462,\"styleCode\":true,\"enableUserHovercards\":true,\"site\":{\"name\":\"Electrical Engineering Stack Exchange\",\"description\":\"Q&A for electronics and electrical engineering professionals, students, and enthusiasts\",\"isNoticesTabEnabled\":true,\"recaptchaPublicKey\":\"6LdsB7sSAAAAAAzjgEF_Hd8vXv-C42sa_KyofaGR\",\"enableSocialMediaInSharePopup\":true},\"user\":{\"fkey\":\"964caaf8350dc8ae69af722ba29b4a1d\",\"isAnonymous\":true}});\n" " StackExchange.using.setCacheBreakers({\"js/prettify-full.js\":\"6c261bebf56a\",\"js/moderator.js\":\"ed7a8238b2f8\",\"js/full-anon.js\":\"5f9bf5810297\",\"js/full.js\":\"027ac5ea264e\",\"js/wmd.js\":\"cff10cca4fd9\",\"js/third-party/jquery.autocomplete.min.js\":\"e5f01e97f7c3\",\"js/mobile.js\":\"82a79dbb7259\",\"js/help.js\":\"6e6623243cf6\",\"js/tageditor.js\":\"450c9e8426fc\",\"js/tageditornew.js\":\"b6c68ad4c7dd\",\"js/inline-tag-editing.js\":\"8e84e8a137f7\",\"js/revisions.js\":\"d3e781ee5528\",\"js/review.js\":\"947758ba83ea\",\"js/tagsuggestions.js\":\"aa48ef6154df\",\"js/post-validation.js\":\"bb996020492a\",\"js/explore-qlist.js\":\"1c5bbd79b562\",\"js/events.js\":\"27a33f0b2cad\"});\n" " StackExchange.using.setCacheBreakers({\"js/mathjax-editing.js\":\"6da1b6cfe19f\",\"js/external-editor.js\":\"51c0a8d46d29\"});\n" " </script>\n" " <script type=\"text/javascript\">\n" " StackExchange.using(\"gps\", function() {\n" " StackExchange.gps.init(true);\n" " });\n" " </script>\n\n" " <script type=\"text/javascript\">\n" " StackExchange.ready(function () {\n" " $('#nav-tour').click(function () {\n" " StackExchange.using(\"gps\", function() {\n" " StackExchange.gps.track(\"aboutpage.click\", { aboutclick_location: \"headermain\" }, true);\n" " });\n" " });\n" " });\n" " </script>\n" "</head>\n" "<body class=\"questions-page\">\n" " <noscript><div id=\"noscript-padding\"></div></noscript>\n" " <div id=\"notify-container\"></div>\n" " <div id=\"overlay-header\"></div>\n" " <div id=\"custom-header\"></div>\n\n" " <div class=\"container\">\n" " <div id=\"header\" class=headeranon>\n" " <div id=\"portalLink\">\n" " <a class=\"genu\" href=\"http://stackexchange.com\" onclick=\"StackExchange.ready(function(){genuwine.click();});return false;\">Stack Exchange</a>\n" " </div>\n" " <div id=\"topbar\">\n" " <div id=\"hlinks\">\n\n" "<span id=\"hlinks-user\"></span>\n" "<span id=\"hlinks-nav\"> <a href=\"/users/login?returnurl=%2fquestions%3fpage%3d2%26sort%3dnewest\">sign up</a>\n\n" " <span class=\"lsep\">|</span>\n" " <a href=\"/users/login?returnurl=%2fquestions%3fpage%3d2%26sort%3dnewest\">log in</a>\n\n" " <span class=\"lsep\">|</span>\n" "</span>\n" "<span id=\"hlinks-custom\"></span>\n" " </div>\n" " <div id=\"hsearch\">\n" " <form id=\"search\" action=\"/search\" method=\"get\" autocomplete=\"off\">\n" " <div>\n" " <input autocomplete=\"off\" name=\"q\" class=\"textbox\" placeholder=\"search\" tabindex=\"1\" type=\"text\" maxlength=\"240\" size=\"28\" value=\"\">\n" " </div>\n" " </form>\n" " </div>\n" " </div>\n" " <br class=\"cbt\">\n" " <div id=\"hlogo\">\n" " <a href=\"/\">\n" " Electrical Engineering\n" " </a>\n" " </div>\n" " <div id=\"hmenus\">\n" " <div class=\"nav mainnavs mainnavsanon\">\n" " <ul>\n" " <li class=\"youarehere\"><a id=\"nav-questions\" href=\"/questions\">Questions</a></li>\n" " <li><a id=\"nav-tags\" href=\"/tags\">Tags</a></li>\n" " <li><a id=\"nav-tour\" href=\"/about\">Tour</a></li>\n" " <li><a id=\"nav-users\" href=\"/users\">Users</a></li>\n" " </ul>\n" " </div>\n" " <div class=\"nav askquestion\">\n" " <ul>\n" " <li>\n" " <a id=\"nav-askquestion\" href=\"/questions/ask\">Ask Question</a>\n" " </li>\n" " </ul>\n" " </div>\n" " </div>\n" " </div>\n\n\n\n\n" " <div id=\"content\">\n\n" "<div id=\"mainbar\">\n" " <div class=\"subheader\">\n" " <h1 id=\"h-all-questions\">All Questions</h1>\n" " <div id=\"tabs\">\n" "<a class=\"youarehere\" href=\"/questions?sort=newest\" title=\"the most recently asked questions\">newest</a>\n" "<a href=\"/questions?sort=featured\" title=\"questions with open bounties\"><span class='bounty-indicator-tab'>3</span>featured</a>\n" "<a href=\"/questions?sort=frequent\" title=\"questions with the most links\">frequent</a>\n" "<a href=\"/questions?sort=votes\" title=\"questions with the most votes\">votes</a>\n" "<a href=\"/questions?sort=active\" title=\"questions that have recent activity\">active</a>\n" "<a href=\"/questions?sort=unanswered\" title=\"questions that have no upvoted answers\">unanswered</a>\n\n" " </div>\n" " </div>\n\n" " <div id=\"questions\">\n\n" "<div class=\"question-summary\" id=\"question-summary-80417\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>1</strong></span>\n" " <div class=\"viewcount\">vote</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>2</strong>answers\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"65 views\">\n" " 65 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80417/can-i-safely-enclose-battery-powered-electronics-in-an-antistatic-bag-to-protect\" class=\"question-hyperlink\">Can I safely enclose battery-powered electronics in an antistatic bag to protect it from static electricity?</a></h3>\n" " <div class=\"excerpt\">\n" " I am building an enclosure for a Beaglebone and external circuit that I want to be able to wear, and therefore want to be lightweight and somewhat comfortable. I power the Beaglebone using a battery ...\n" " </div>\n\n" " <div class=\"tags t-shielding t-antistatic t-static\">\n" " <a href=\"/questions/tagged/shielding\" class=\"post-tag\" title=\"show questions tagged 'shielding'\" rel=\"tag\">shielding</a> <a href=\"/questions/tagged/antistatic\" class=\"post-tag\" title=\"show questions tagged 'antistatic'\" rel=\"tag\">antistatic</a> <a href=\"/questions/tagged/static\" class=\"post-tag\" title=\"show questions tagged 'static'\" rel=\"tag\">static</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 22:47:03Z\" class=\"relativetime\">11 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/19783/mokogobo\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/045025756373a85e8336c8126ee006c6?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/19783/mokogobo\">mokogobo</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">31</span><span title=\"4 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">4</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80412\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>0</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"22 views\">\n" " 22 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80412/how-to-overwrite-flash-memory-on-stm32l-series\" class=\"question-hyperlink\">How to overwrite flash memory on STM32L series</a></h3>\n" " <div class=\"excerpt\">\n" " I am trying to write a known pattern (ie 0xFFFFFFFF or 0x00000000) on top of already written flash memory, to invalidate portions of it for a primitive file system. But it doesn't work for me on the ...\n" " </div>\n\n" " <div class=\"tags t-stm32 t-flash\">\n" " <a href=\"/questions/tagged/stm32\" class=\"post-tag\" title=\"show questions tagged 'stm32'\" rel=\"tag\">stm32</a> <a href=\"/questions/tagged/flash\" class=\"post-tag\" title=\"show questions tagged 'flash'\" rel=\"tag\">flash</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 22:09:01Z\" class=\"relativetime\">12 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/15757/mark-lakata\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/5fd80d98f96f9adbde7876cbda181715?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/15757/mark-lakata\">Mark Lakata</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">111</span><span title=\"2 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">2</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80407\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>2</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"61 views\">\n" " 61 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80407/about-power-supply-of-opertional-amplifier\" class=\"question-hyperlink\">about power supply of opertional amplifier</a></h3>\n" " <div class=\"excerpt\">\n" " I am constructing an operational amplifier as shown in the following figure. I use a batter as supplier for the OP Amp and set it up as a non-inverting amp circuit. I saw that the output was clipped ...\n" " </div>\n\n" " <div class=\"tags t-op-amp\">\n" " <a href=\"/questions/tagged/op-amp\" class=\"post-tag\" title=\"show questions tagged 'op-amp'\" rel=\"tag\">op-amp</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 21:49:14Z\" class=\"relativetime\">12 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/17060/user1285419\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/08ee68b20a4eceff26f7eee99b708c08?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/17060/user1285419\">user1285419</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">165</span><span title=\"5 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">5</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80405\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>4</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered-accepted\">\n" " <strong>2</strong>answers\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"64 views\">\n" " 64 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80405/5v-regulator-power-dissipation\" class=\"question-hyperlink\">5V Regulator Power Dissipation</a></h3>\n" " <div class=\"excerpt\">\n" " I am using a 5V regulator (LP2950) from ON Semiconductor. I am using this for USB power and I'm feeding in 9V from an adapter. USB requires maximum of 500mA right? So the maximum power dissipation in ...\n" " </div>\n\n" " <div class=\"tags t-voltage-regulator t-surface-mount t-heatsink t-5v t-power-dissipation\">\n" " <a href=\"/questions/tagged/voltage-regulator\" class=\"post-tag\" title=\"show questions tagged 'voltage-regulator'\" rel=\"tag\">voltage-regulator</a> <a href=\"/questions/tagged/surface-mount\" class=\"post-tag\" title=\"show questions tagged 'surface-mount'\" rel=\"tag\">surface-mount</a> <a href=\"/questions/tagged/heatsink\" class=\"post-tag\" title=\"show questions tagged 'heatsink'\" rel=\"tag\">heatsink</a> <a href=\"/questions/tagged/5v\" class=\"post-tag\" title=\"show questions tagged '5v'\" rel=\"tag\">5v</a> <a href=\"/questions/tagged/power-dissipation\" class=\"post-tag\" title=\"show questions tagged 'power-dissipation'\" rel=\"tag\">power-dissipation</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 21:39:31Z\" class=\"relativetime\">13 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/10082/david-norman\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/8b073417e471077280b3fc5ff2eaf1f7?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/10082/david-norman\">David Norman</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">322</span><span title=\"3 silver badges\"><span class=\"badge2\"></span><span class=\"badgecount\">3</span></span><span title=\"10 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">10</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80404\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>0</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"44 views\">\n" " 44 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80404/how-to-stop-two-dc-motors-simultaneously-using-limit-switches\" class=\"question-hyperlink\">How to stop two DC motors simultaneously using limit switches</a></h3>\n" " <div class=\"excerpt\">\n" " I need some help - I'm building a machine but I'm not sure of the best way of doing it.\n\n" "I have three large wire spools. Two empty and one full. The full spool (approx. 500kg) is much larger than the ...\n" " </div>\n\n" " <div class=\"tags t-dc-motor t-switch-mode-power-supply t-servo t-plc t-toggle-switch\">\n" " <a href=\"/questions/tagged/dc-motor\" class=\"post-tag\" title=\"show questions tagged 'dc-motor'\" rel=\"tag\">dc-motor</a> <a href=\"/questions/tagged/switch-mode-power-supply\" class=\"post-tag\" title=\"show questions tagged 'switch-mode-power-supply'\" rel=\"tag\">switch-mode-power-supply</a> <a href=\"/questions/tagged/servo\" class=\"post-tag\" title=\"show questions tagged 'servo'\" rel=\"tag\">servo</a> <a href=\"/questions/tagged/plc\" class=\"post-tag\" title=\"show questions tagged 'plc'\" rel=\"tag\">plc</a> <a href=\"/questions/tagged/toggle-switch\" class=\"post-tag\" title=\"show questions tagged 'toggle-switch'\" rel=\"tag\">toggle-switch</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 21:29:47Z\" class=\"relativetime\">13 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/28090/golden-bucky\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/0d00cc71566104e18dc131bc7f5b4cf1?s=32&d=identicon&r=PG&f=1\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/28090/golden-bucky\">Golden Bucky</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">1</span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80396\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>1</strong></span>\n" " <div class=\"viewcount\">vote</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"58 views\">\n" " 58 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80396/logic-level-translator-caveats\" class=\"question-hyperlink\">Logic Level Translator caveats</a></h3>\n" " <div class=\"excerpt\">\n" " I have a device that runs on 2.5Vcmos logic levels, there are about a half dozen ic's with a mixture of parallel and serial (TWI and I2C) signal lines. Rather than placing my own uC on the board I'd ...\n" " </div>\n\n" " <div class=\"tags t-level-translation\">\n" " <a href=\"/questions/tagged/level-translation\" class=\"post-tag\" title=\"show questions tagged 'level-translation'\" rel=\"tag\">level-translation</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 20:45:03Z\" class=\"relativetime\">13 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/1729/crasic\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/61084e40f265986dd41136b4f3dc028f?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/1729/crasic\">crasic</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">643</span><span title=\"2 silver badges\"><span class=\"badge2\"></span><span class=\"badgecount\">2</span></span><span title=\"8 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">8</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80393\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>1</strong></span>\n" " <div class=\"viewcount\">vote</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"57 views\">\n" " 57 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80393/microcontroller-newbe-here-led-color-pattern-controller-for-arcade-machine\" class=\"question-hyperlink\">Microcontroller Newbe here. LED color pattern controller for arcade machine [on hold]</a></h3>\n" " <div class=\"excerpt\">\n" " I am building an arcade machine and I want to make a cool led light display for the marquee.\n\n" "You can see pictures of what I'm talking about here.\n\n\n\n\n\n" "I want to light up each one of those holes with ...\n" " </div>\n\n" " <div class=\"tags t-microcontroller t-led\">\n" " <a href=\"/questions/tagged/microcontroller\" class=\"post-tag\" title=\"show questions tagged 'microcontroller'\" rel=\"tag\">microcontroller</a> <a href=\"/questions/tagged/led\" class=\"post-tag\" title=\"show questions tagged 'led'\" rel=\"tag\">led</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 20:34:56Z\" class=\"relativetime\">14 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/28086/doug-steinberg\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/f8a5cf563e719e934263883978ab80f1?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/28086/doug-steinberg\">Doug Steinberg</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">6</span><span title=\"1 bronze badge\"><span class=\"badge3\"></span><span class=\"badgecount\">1</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80385\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>1</strong></span>\n" " <div class=\"viewcount\">vote</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>2</strong>answers\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"69 views\">\n" " 69 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80385/how-to-scale-dynamic-range-voltage-to-1-5-volt\" class=\"question-hyperlink\">how to scale dynamic range voltage to 1-5 volt</a></h3>\n" " <div class=\"excerpt\">\n" " how can i make circuit that scale input voltage that have dynamic range to 1-5 volt output?\n\n\n\n" "the circuit will have Vref+ and Vref- as maximum and minimum for Vinput and then scale to 1-5 volt output\n" "...\n" " </div>\n\n" " <div class=\"tags t-voltage t-amplifier\">\n" " <a href=\"/questions/tagged/voltage\" class=\"post-tag\" title=\"show questions tagged 'voltage'\" rel=\"tag\">voltage</a> <a href=\"/questions/tagged/amplifier\" class=\"post-tag\" title=\"show questions tagged 'amplifier'\" rel=\"tag\">amplifier</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 19:30:33Z\" class=\"relativetime\">15 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/28084/user28084\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/2cacd24f99b2bcbd8236d1ce8c3c559f?s=32&d=identicon&r=PG&f=1\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/28084/user28084\">user28084</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">9</span><span title=\"2 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">2</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80383\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>0</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered-accepted\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"38 views\">\n" " 38 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80383/is-it-the-frequency-that-determines-the-current-in-a-lc-tank-parallel-circuit\" class=\"question-hyperlink\">Is it the frequency that determines the current in a LC Tank Parallel Circuit?</a></h3>\n" " <div class=\"excerpt\">\n" " Jump a head to the question if you aren't interested in the background of my project\n\n" "Background of my project\n\n" "I want to create objects of metal. So I need to be able to cast a metal. Aluminium seems ...\n" " </div>\n\n" " <div class=\"tags t-current t-frequency t-solenoid t-induction t-rlc\">\n" " <a href=\"/questions/tagged/current\" class=\"post-tag\" title=\"show questions tagged 'current'\" rel=\"tag\">current</a> <a href=\"/questions/tagged/frequency\" class=\"post-tag\" title=\"show questions tagged 'frequency'\" rel=\"tag\">frequency</a> <a href=\"/questions/tagged/solenoid\" class=\"post-tag\" title=\"show questions tagged 'solenoid'\" rel=\"tag\">solenoid</a> <a href=\"/questions/tagged/induction\" class=\"post-tag\" title=\"show questions tagged 'induction'\" rel=\"tag\">induction</a> <a href=\"/questions/tagged/rlc\" class=\"post-tag\" title=\"show questions tagged 'rlc'\" rel=\"tag\">rlc</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 19:29:24Z\" class=\"relativetime\">15 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/26135/mike-de-klerk\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/7c2d61f7fedb644912d1cef5ed0b250a?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/26135/mike-de-klerk\">Mike de Klerk</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">183</span><span title=\"6 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">6</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80378\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>4</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered-accepted\">\n" " <strong>4</strong>answers\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"54 views\">\n" " 54 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80378/replacing-resistors-with-equivalent-resistor\" class=\"question-hyperlink\">Replacing resistors with equivalent resistor</a></h3>\n" " <div class=\"excerpt\">\n" " This is somewhat a homework assignment, but please bear with me. Given the following schematic, I want to know the overall resistance when measured from node A to node B.\n\n\n\n\n\n\n\n" "simulate this circuit ...\n" " </div>\n\n" " <div class=\"tags t-resistors t-resistance t-circuit-analysis\">\n" " <a href=\"/questions/tagged/resistors\" class=\"post-tag\" title=\"show questions tagged 'resistors'\" rel=\"tag\">resistors</a> <a href=\"/questions/tagged/resistance\" class=\"post-tag\" title=\"show questions tagged 'resistance'\" rel=\"tag\">resistance</a> <a href=\"/questions/tagged/circuit-analysis\" class=\"post-tag\" title=\"show questions tagged 'circuit-analysis'\" rel=\"tag\">circuit-analysis</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 19:07:14Z\" class=\"relativetime\">15 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/9913/nijansen\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/8250825c174a99613ffeec2ccc085bcf?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/9913/nijansen\">nijansen</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">174</span><span title=\"8 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">8</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80371\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>2</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>2</strong>answers\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"32 views\">\n" " 32 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80371/saturation-current-in-inductor-definition\" class=\"question-hyperlink\">Saturation current in inductor - Definition?</a></h3>\n" " <div class=\"excerpt\">\n" " Can somebody explain me what actually is a saturation current of an inductor. You may consider one inductor too and explain the things. This is very much confusing for me. Somebody give me a clear cut ...\n" " </div>\n\n" " <div class=\"tags t-inductor\">\n" " <a href=\"/questions/tagged/inductor\" class=\"post-tag\" title=\"show questions tagged 'inductor'\" rel=\"tag\">inductor</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 18:38:03Z\" class=\"relativetime\">16 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/20352/durgaprasad\"><div class=\"gravatar-wrapper-32\"><img src=\"http://i.stack.imgur.com/iQDud.jpg?s=32&g=1\" alt=\"\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/20352/durgaprasad\">Durgaprasad</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">339</span><span title=\"9 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">9</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80370\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>3</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>2</strong>answers\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"85 views\">\n" " 85 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80370/is-it-possible-for-batteries-to-give-a-false-reading-of-being-charged-with-a-mul\" class=\"question-hyperlink\">Is it possible for batteries to give a false reading of being charged with a multimeter?</a></h3>\n" " <div class=\"excerpt\">\n" " I bought a Stanley SL5W09L spotlight about four years ago and it has performed wonderfully ever since. Recently however it has stopped working.\n\n" "I can plug it in, and the charge light will come on ...\n" " </div>\n\n" " <div class=\"tags t-batteries\">\n" " <a href=\"/questions/tagged/batteries\" class=\"post-tag\" title=\"show questions tagged 'batteries'\" rel=\"tag\">batteries</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 18:36:29Z\" class=\"relativetime\">16 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/24413/steve-french\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/ef46e9c26326bd9d82479c7daf4155a3?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/24413/steve-french\">Steve French</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">119</span><span title=\"1 bronze badge\"><span class=\"badge3\"></span><span class=\"badgecount\">1</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80366\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>0</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"37 views\">\n" " 37 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80366/arduino-accessing-extra-analog-pins-on-32-pin-smt-package\" class=\"question-hyperlink\">Arduino - accessing extra analog pins on 32-pin SMT package</a></h3>\n" " <div class=\"excerpt\">\n" " I've got a 32-pin ATMega328 on a breadboard. I have its analog pin #6 as an input pin from another IC on my board. The IC sends data to this analog pin.\n\n" "Now, the ATMega328 DIP package (used on the ...\n" " </div>\n\n" " <div class=\"tags t-arduino\">\n" " <a href=\"/questions/tagged/arduino\" class=\"post-tag\" title=\"show questions tagged 'arduino'\" rel=\"tag\">arduino</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 18:07:58Z\" class=\"relativetime\">16 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/17082/ryan-tuck\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/57bb887b039eb0ca9f976210fe821a2a?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/17082/ryan-tuck\">Ryan Tuck</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">114</span><span title=\"5 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">5</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80365\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>6</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered-accepted\">\n" " <strong>4</strong>answers\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"88 views\">\n" " 88 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80365/capacitor-inrush-current\" class=\"question-hyperlink\">Capacitor Inrush Current</a></h3>\n" " <div class=\"excerpt\">\n" " I have to filter a power control circuit and as usual I am using lots of capacitors in parallel. Some of these capacitors are Tantalum or Aluminium Polymer types, with ripple current ratings of 3 amps ...\n" " </div>\n\n" " <div class=\"tags t-capacitor t-inrush-current\">\n" " <a href=\"/questions/tagged/capacitor\" class=\"post-tag\" title=\"show questions tagged 'capacitor'\" rel=\"tag\">capacitor</a> <a href=\"/questions/tagged/inrush-current\" class=\"post-tag\" title=\"show questions tagged 'inrush-current'\" rel=\"tag\">inrush-current</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info user-hover\">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 18:04:39Z\" class=\"relativetime\">16 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/15955/mfeinstein\"><div class=\"\"><img src=\"https://www.gravatar.com/avatar/86b9f964b2a1d7cc66a78a6199801f71?s=32&d=identicon&r=PG\" alt=\"\" width=\"32\" height=\"32\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/15955/mfeinstein\">mFeinstein</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">1,006</span><span title=\"11 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">11</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n\n" "<div class=\"question-summary\" id=\"question-summary-80360\">\n" " <div class=\"statscontainer\">\n" " <div class=\"statsarrow\"></div>\n" " <div class=\"stats\">\n" " <div class=\"vote\">\n" " <div class=\"votes\">\n" " <span class=\"vote-count-post \"><strong>0</strong></span>\n" " <div class=\"viewcount\">votes</div>\n" " </div>\n" " </div>\n" " <div class=\"status answered\">\n" " <strong>1</strong>answer\n" " </div>\n" " </div>\n\n\n\n" "<div class=\"views \" title=\"28 views\">\n" " 28 views\n" "</div>\n" " </div>\n" " <div class=\"summary\">\n" " <h3><a href=\"/questions/80360/designing-adc-driver-circuit-using-ltc6406\" class=\"question-hyperlink\">Designing ADC driver circuit using LTC6406</a></h3>\n" " <div class=\"excerpt\">\n" " I am designing the front end(single ended to differential) for the ADC using LTC6406 to interface with the 20MSPS ADC. My input frequency is 140 MHz.\n" "Simulation Sch is shown below:\n\n" "L1, L2 and C1 are ...\n" " </div>\n\n" " <div class=\"tags t-circuit t-adc\">\n" " <a href=\"/questions/tagged/circuit\" class=\"post-tag\" title=\"show questions tagged 'circuit'\" rel=\"tag\">circuit</a> <a href=\"/questions/tagged/adc\" class=\"post-tag\" title=\"show questions tagged 'adc'\" rel=\"tag\">adc</a>\n\n" " </div>\n" " <div class=\"started fr\">\n\n\n" " <div class=\"user-info \">\n" " <div class=\"user-action-time\">\n\n\n" " asked <span title=\"2013-08-27 17:36:42Z\" class=\"relativetime\">17 hours ago</span>\n" " </div>\n" " <div class=\"user-gravatar32\">\n" " <a href=\"/users/25017/anand-kumar-rai\"><div class=\"gravatar-wrapper-32\"><img src=\"http://i.stack.imgur.com/v6adE.jpg?s=32&g=1\" alt=\"\"></div></a>\n" " </div>\n" " <div class=\"user-details\">\n" " <a href=\"/users/25017/anand-kumar-rai\">Anand Kumar Rai</a><br>\n" " <span class=\"reputation-score\" title=\"reputation score\" dir=\"ltr\">183</span><span title=\"1 silver badge\"><span class=\"badge2\"></span><span class=\"badgecount\">1</span></span><span title=\"10 bronze badges\"><span class=\"badge3\"></span><span class=\"badgecount\">10</span></span>\n" " </div>\n" " </div>\n\n" " </div>\n" " </div>\n" "</div>\n" " </div>\n\n" " <br class=\"cbt\">\n\n\n" " <div class=\"page-sizer fr\">\n" " <a href=\"/questions?pagesize=15&amp;sort=newest\" title=\"show 15 items per page\" class=\"page-numbers current\">15</a>\n" " <a href=\"/questions?pagesize=30&amp;sort=newest\" title=\"show 30 items per page\" class=\"page-numbers \">30</a>\n" " <a href=\"/questions?pagesize=50&amp;sort=newest\" title=\"show 50 items per page\" class=\"page-numbers \">50</a>\n" " <span class=\"page-numbers desc\">per page</span>\n" " </div>\n" "<div class=\"pager fl\" >\n" "<a href=\"/questions?page=1&amp;sort=newest\" title=\"go to page 1\" rel=\"prev\"><span class=\"page-numbers prev\">prev </span></a>\n" "<a href=\"/questions?page=1&amp;sort=newest\" title=\"go to page 1\"><span class=\"page-numbers\">1</span></a>\n" "<span class=\"page-numbers current\">2</span>\n" "<a href=\"/questions?page=3&amp;sort=newest\" title=\"go to page 3\"><span class=\"page-numbers\">3</span></a>\n" "<a href=\"/questions?page=4&amp;sort=newest\" title=\"go to page 4\"><span class=\"page-numbers\">4</span></a>\n" "<a href=\"/questions?page=5&amp;sort=newest\" title=\"go to page 5\"><span class=\"page-numbers\">5</span></a>\n" "<span class=\"page-numbers dots\">&hellip;</span>\n" "<a href=\"/questions?page=1340&amp;sort=newest\" title=\"go to page 1340\"><span class=\"page-numbers\">1340</span></a>\n" "<a href=\"/questions?page=3&amp;sort=newest\" title=\"go to page 3\" rel=\"next\"><span class=\"page-numbers next\"> next</span></a>\n" "</div>\n\n" "</div>\n" "<div id=\"sidebar\">\n" " <div class=\"module\" id=\"questions-count\">\n" " <div class=\"summarycount al\">20,098</div>\n" " <p>questions</p>\n" " </div>\n\n\n\n\n\n\n\n" " <div class=\"module\" id=\"related-tags\">\n" " <h4 id=\"h-related-tags\">Related Tags</h4>\n\n" " <a href=\"/questions/tagged/arduino\" class=\"post-tag\" title=\"show questions tagged 'arduino'\" rel=\"tag\">arduino</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">2030</span></span><br>\n" " <a href=\"/questions/tagged/microcontroller\" class=\"post-tag\" title=\"show questions tagged 'microcontroller'\" rel=\"tag\">microcontroller</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">1432</span></span><br>\n" " <a href=\"/questions/tagged/power-supply\" class=\"post-tag\" title=\"show questions tagged 'power-supply'\" rel=\"tag\">power-supply</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">899</span></span><br>\n" " <a href=\"/questions/tagged/led\" class=\"post-tag\" title=\"show questions tagged 'led'\" rel=\"tag\">led</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">789</span></span><br>\n" " <a href=\"/questions/tagged/pic\" class=\"post-tag\" title=\"show questions tagged 'pic'\" rel=\"tag\">pic</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">735</span></span><br>\n" " <a href=\"/questions/tagged/power\" class=\"post-tag\" title=\"show questions tagged 'power'\" rel=\"tag\">power</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">730</span></span><br>\n" " <a href=\"/questions/tagged/voltage\" class=\"post-tag\" title=\"show questions tagged 'voltage'\" rel=\"tag\">voltage</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">608</span></span><br>\n" " <a href=\"/questions/tagged/batteries\" class=\"post-tag\" title=\"show questions tagged 'batteries'\" rel=\"tag\">batteries</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">593</span></span><br>\n" " <a href=\"/questions/tagged/transistors\" class=\"post-tag\" title=\"show questions tagged 'transistors'\" rel=\"tag\">transistors</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">577</span></span><br>\n" " <a href=\"/questions/tagged/pcb\" class=\"post-tag\" title=\"show questions tagged 'pcb'\" rel=\"tag\">pcb</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">570</span></span><br>\n" " <a href=\"/questions/tagged/capacitor\" class=\"post-tag\" title=\"show questions tagged 'capacitor'\" rel=\"tag\">capacitor</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">564</span></span><br>\n" " <a href=\"/questions/tagged/usb\" class=\"post-tag\" title=\"show questions tagged 'usb'\" rel=\"tag\">usb</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">538</span></span><br>\n" " <a href=\"/questions/tagged/digital-logic\" class=\"post-tag\" title=\"show questions tagged 'digital-logic'\" rel=\"tag\">digital-logic</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">522</span></span><br>\n" " <a href=\"/questions/tagged/sensor\" class=\"post-tag\" title=\"show questions tagged 'sensor'\" rel=\"tag\">sensor</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">500</span></span><br>\n" " <a href=\"/questions/tagged/avr\" class=\"post-tag\" title=\"show questions tagged 'avr'\" rel=\"tag\">avr</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">493</span></span><br>\n" " <a href=\"/questions/tagged/op-amp\" class=\"post-tag\" title=\"show questions tagged 'op-amp'\" rel=\"tag\">op-amp</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">447</span></span><br>\n" " <a href=\"/questions/tagged/current\" class=\"post-tag\" title=\"show questions tagged 'current'\" rel=\"tag\">current</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">436</span></span><br>\n" " <a href=\"/questions/tagged/fpga\" class=\"post-tag\" title=\"show questions tagged 'fpga'\" rel=\"tag\">fpga</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">431</span></span><br>\n" " <a href=\"/questions/tagged/circuit\" class=\"post-tag\" title=\"show questions tagged 'circuit'\" rel=\"tag\">circuit</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">423</span></span><br>\n" " <a href=\"/questions/tagged/resistors\" class=\"post-tag\" title=\"show questions tagged 'resistors'\" rel=\"tag\">resistors</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">394</span></span><br>\n" " <a href=\"/questions/tagged/audio\" class=\"post-tag\" title=\"show questions tagged 'audio'\" rel=\"tag\">audio</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">394</span></span><br>\n" " <a href=\"/questions/tagged/motor\" class=\"post-tag\" title=\"show questions tagged 'motor'\" rel=\"tag\">motor</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">384</span></span><br>\n" " <a href=\"/questions/tagged/voltage-regulator\" class=\"post-tag\" title=\"show questions tagged 'voltage-regulator'\" rel=\"tag\">voltage-regulator</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">377</span></span><br>\n" " <a href=\"/questions/tagged/mosfet\" class=\"post-tag\" title=\"show questions tagged 'mosfet'\" rel=\"tag\">mosfet</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">374</span></span><br>\n" " <a href=\"/questions/tagged/switches\" class=\"post-tag\" title=\"show questions tagged 'switches'\" rel=\"tag\">switches</a>&nbsp;<span class=\"item-multiplier\"><span class=\"item-multiplier-x\">&times;</span>&nbsp;<span class=\"item-multiplier-count\">344</span></span><br>\n" " </div>\n" "</div>\n\n" " </div>\n" " </div>\n" " <div id=\"footer\" class=\"categories\">\n" " <div class=\"footerwrap\">\n" " <div id=\"footer-menu\">\n" " <div class=\"top-footer-links\">\n" " <a href=\"/about\">about</a>\n" " <a href=\"/help\">help</a>\n" " <a href=\"/help/badges\">badges</a>\n" " <a href=\"http://blog.stackexchange.com?blb=1\">blog</a>\n" " <a href=\"http://chat.stackexchange.com\">chat</a>\n" " <a href=\"http://data.stackexchange.com\">data</a>\n" " <a href=\"http://stackexchange.com/legal\">legal</a>\n" " <a href=\"http://stackexchange.com/legal/privacy-policy\">privacy policy</a>\n" " <a href=\"http://stackexchange.com/about/hiring\">jobs</a>\n" " <a href=\"http://stackexchange.com/about/contact\">advertising info</a>\n\n" " <a onclick='StackExchange.switchMobile(\"on\", \"/questions?page=2&amp;sort=newest\")'>mobile</a>\n" " <b><a href=\"/contact\">contact us</a></b>\n" " <b><a href=\"http://meta.electronics.stackexchange.com\">feedback</a></b>\n\n" " </div>\n" " <div id=\"footer-sites\">\n" " <table>\n" " <tr>\n" " <th colspan=3>\n" " Technology\n" " </th>\n" " <th >\n" " Life / Arts\n" " </th>\n" " <th >\n" " Culture / Recreation\n" " </th>\n" " <th >\n" " Science\n" " </th>\n" " <th >\n" " Other\n" " </th>\n" " </tr>\n" " <tr>\n" " <td>\n" " <ol>\n" " <li><a href=\"http://stackoverflow.com\" title=\"professional and enthusiast programmers\">Stack Overflow</a></li>\n" " <li><a href=\"http://serverfault.com\" title=\"professional system and network administrators\">Server Fault</a></li>\n" " <li><a href=\"http://superuser.com\" title=\"computer enthusiasts and power users\">Super User</a></li>\n" " <li><a href=\"http://webapps.stackexchange.com\" title=\"power users of web applications\">Web Applications</a></li>\n" " <li><a href=\"http://askubuntu.com\" title=\"Ubuntu users and developers\">Ask Ubuntu</a></li>\n" " <li><a href=\"http://webmasters.stackexchange.com\" title=\"pro webmasters\">Webmasters</a></li>\n" " <li><a href=\"http://gamedev.stackexchange.com\" title=\"professional and independent game developers\">Game Development</a></li>\n" " <li><a href=\"http://tex.stackexchange.com\" title=\"users of TeX, LaTeX, ConTeXt, and related typesetting systems\">TeX - LaTeX</a></li>\n" " </ol></td><td><ol>\n" " <li><a href=\"http://programmers.stackexchange.com\" title=\"professional programmers interested in conceptual questions about software development\">Programmers</a></li>\n" " <li><a href=\"http://unix.stackexchange.com\" title=\"users of Linux, FreeBSD and other Un*x-like operating systems.\">Unix &amp; Linux</a></li>\n" " <li><a href=\"http://apple.stackexchange.com\" title=\"power users of Apple hardware and software\">Ask Different (Apple)</a></li>\n" " <li><a href=\"http://wordpress.stackexchange.com\" title=\"WordPress developers and administrators\">WordPress Answers</a></li>\n" " <li><a href=\"http://gis.stackexchange.com\" title=\"cartographers, geographers and GIS professionals\">Geographic Information Systems</a></li>\n" " <li><a href=\"http://electronics.stackexchange.com\" title=\"electronics and electrical engineering professionals, students, and enthusiasts\">Electrical Engineering</a></li>\n" " <li><a href=\"http://android.stackexchange.com\" title=\"enthusiasts and power users of the Android operating system\">Android Enthusiasts</a></li>\n" " <li><a href=\"http://security.stackexchange.com\" title=\"IT security professionals\">IT Security</a></li>\n" " </ol></td><td><ol>\n" " <li><a href=\"http://dba.stackexchange.com\" title=\"database professionals who wish to improve their database skills and learn from others in the community\">Database Administrators</a></li>\n" " <li><a href=\"http://drupal.stackexchange.com\" title=\"Drupal developers and administrators\">Drupal Answers</a></li>\n" " <li><a href=\"http://sharepoint.stackexchange.com\" title=\"SharePoint enthusiasts\">SharePoint</a></li>\n" " <li><a href=\"http://ux.stackexchange.com\" title=\"user experience researchers and experts\">User Experience</a></li>\n" " <li><a href=\"http://mathematica.stackexchange.com\" title=\"users of Mathematica\">Mathematica</a></li>\n\n" " <li>\n" " <a href=\"http://stackexchange.com/sites#technology\" class=\"more\">\n" " more (13)\n" " </a>\n" " </li>\n" " </ol>\n" " </td>\n" " <td>\n" " <ol>\n" " <li><a href=\"http://photo.stackexchange.com\" title=\"professional, enthusiast and amateur photographers\">Photography</a></li>\n" " <li><a href=\"http://scifi.stackexchange.com\" title=\"science fiction and fantasy enthusiasts\">Science Fiction &amp; Fantasy</a></li>\n" " <li><a href=\"http://cooking.stackexchange.com\" title=\"professional and amateur chefs\">Seasoned Advice (cooking)</a></li>\n" " <li><a href=\"http://diy.stackexchange.com\" title=\"contractors and serious DIYers\">Home Improvement</a></li>\n\n" " <li>\n" " <a href=\"http://stackexchange.com/sites#lifearts\" class=\"more\">\n" " more (13)\n" " </a>\n" " </li>\n" " </ol>\n" " </td>\n" " <td>\n" " <ol>\n" " <li><a href=\"http://english.stackexchange.com\" title=\"linguists, etymologists, and serious English language enthusiasts\">English Language &amp; Usage</a></li>\n" " <li><a href=\"http://skeptics.stackexchange.com\" title=\"scientific skepticism\">Skeptics</a></li>\n" " <li><a href=\"http://judaism.stackexchange.com\" title=\"those who base their lives on Jewish law and tradition and anyone interested in learning more\">Mi Yodeya (Judaism)</a></li>\n" " <li><a href=\"http://travel.stackexchange.com\" title=\"road warriors and seasoned travelers\">Travel</a></li>\n" " <li><a href=\"http://christianity.stackexchange.com\" title=\"committed Christians, experts in Christianity and those interested in learning more\">Christianity</a></li>\n" " <li><a href=\"http://gaming.stackexchange.com\" title=\"passionate videogamers on all platforms\">Arqade (gaming)</a></li>\n" " <li><a href=\"http://bicycles.stackexchange.com\" title=\"people who build and repair bicycles, people who train cycling, or commute on bicycles\">Bicycles</a></li>\n" " <li><a href=\"http://rpg.stackexchange.com\" title=\"gamemasters and players of tabletop, paper-and-pencil role-playing games\">Role-playing Games</a></li>\n\n" " <li>\n" " <a href=\"http://stackexchange.com/sites#culturerecreation\" class=\"more\">\n" " more (21)\n" " </a>\n" " </li>\n" " </ol>\n" " </td>\n" " <td>\n" " <ol>\n" " <li><a href=\"http://math.stackexchange.com\" title=\"people studying math at any level and professionals in related fields\">Mathematics</a></li>\n" " <li><a href=\"http://stats.stackexchange.com\" title=\"statisticians, data analysts, data miners and data visualization experts\">Cross Validated (stats)</a></li>\n" " <li><a href=\"http://cstheory.stackexchange.com\" title=\"theoretical computer scientists and researchers in related fields\">Theoretical Computer Science</a></li>\n" " <li><a href=\"http://physics.stackexchange.com\" title=\"active researchers, academics and students of physics\">Physics</a></li>\n" " <li><a href=\"http://mathoverflow.net\" title=\"professional mathematicians\">MathOverflow</a></li>\n\n" " <li>\n" " <a href=\"http://stackexchange.com/sites#science\" class=\"more\">\n" " more (7)\n" " </a>\n" " </li>\n" " </ol>\n" " </td>\n" " <td>\n" " <ol>\n" " <li><a href=\"http://stackapps.com\" title=\"apps, scripts, and development with the Stack Exchange API\">Stack Apps</a></li>\n" " <li><a href=\"http://meta.stackoverflow.com\" title=\"meta-discussion of the Stack Exchange family of Q&amp;A websites\">Meta Stack Overflow</a></li>\n" " <li><a href=\"http://area51.stackexchange.com\" title=\"proposing new sites in the Stack Exchange network\">Area 51</a></li>\n" " <li><a href=\"http://careers.stackoverflow.com\">Stack Overflow Careers</a></li>\n\n" " </ol>\n" " </td>\n" " </tr>\n" "</table>\n" " </div>\n" " </div>\n\n" " <div id=\"copyright\">\n" " site design / logo &copy; 2013 stack exchange inc;\n" " user contributions licensed under <a href=\"http://creativecommons.org/licenses/by-sa/3.0/\" rel=\"license\">cc-wiki</a>\n" " with <a href=\"http://blog.stackoverflow.com/2009/06/attribution-required/\" rel=\"license\">attribution required</a>\n" " </div>\n" " <div id=\"footer-flair\">\n" " <a href=\"http://creativecommons.org/licenses/by-sa/3.0/\" class=\"cc-wiki-link\"></a>\n" " </div>\n" " <div id=\"svnrev\">\n" " rev 2013.8.28.977\n" " </div>\n\n" " </div>\n" " </div>\n" " <noscript>\n" " <div id=\"noscript-warning\">Electrical Engineering Stack Exchange works best with JavaScript enabled<img src=\"http://pixel.quantserve.com/pixel/p-c1rF4kxgLUzNc.gif\" alt=\"\" class=\"dno\"></div>\n" " </noscript>\n\n" " <script type=\"text/javascript\">var _gaq=_gaq||[];_gaq.push(['_setAccount','UA-5620270-24']);\n" " _gaq.push(['_setDomainName','.stackexchange.com']);\n" "_gaq.push(['_trackPageview']);\n" " var _qevents = _qevents || [];\n" " (function () {\n" " var ssl='https:'==document.location.protocol,\n" " s=document.getElementsByTagName('script')[0],\n" " ga=document.createElement('script');\n" " ga.type='text/javascript';\n" " ga.async=true;\n" " ga.src=(ssl?'https://ssl':'http://www')+'.google-analytics.com/ga.js';\n" " s.parentNode.insertBefore(ga,s);\n" " var sc=document.createElement('script');\n" " sc.type='text/javascript';\n" " sc.async=true;\n" " sc.src=(ssl?'https://secure':'http://edge')+'.quantserve.com/quant.js';\n" " s.parentNode.insertBefore(sc,s);\n" " })();\n" " _qevents.push({ qacct: \"p-c1rF4kxgLUzNc\" });\n" " </script>\n\n" "</body>\n" "</html>") matches = re.finditer(regex, test_str) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html