Choosing the Right Protection for Digital and ADC Inputs | Electronics Forum (Circuits, Projects and Microcontrollers)

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It may not display this or other websites correctly.<br />You should upgrade or use an <a href="https://www.google.com/chrome/" target="_blank" rel="noopener">alternative browser</a>.</div> <div class="p-body-header"> <div class="p-title "> <h1 class="p-title-value">Choosing the Right Protection for Digital and ADC Inputs</h1> </div> <div class="p-description"> <ul class="listInline listInline--bullet"> <li> <i class="fa--xf fal fa-user" aria-hidden="true" title="Thread starter"></i> <span class="u-srOnly">Thread starter</span> <a href="/members/saeedk9574.323190/" class="username u-concealed" dir="auto" data-user-id="323190" data-xf-init="member-tooltip">Saeedk9574</a> </li> <li> <i class="fa--xf fal fa-clock" aria-hidden="true" title="Start date"></i> <span class="u-srOnly">Start date</span> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/" class="u-concealed"><time class="u-dt" dir="auto" datetime="2024-10-19T03:26:25-0700" data-time="1729333585" data-date-string="Oct 19, 2024" data-time-string="3:26 AM" title="Oct 19, 2024 at 3:26 AM">Oct 19, 2024</time></a> </li> </ul> </div> </div> <div class="p-body-main p-body-main--withSidebar "> <div class="p-body-contentCol"></div> <div class="p-body-sidebarCol"></div> <div class="p-body-content"> <div class="p-body-pageContent"> <div class="block block--messages " data-xf-init="lightbox select-to-quote" data-message-selector=".js-post" data-lb-id="thread-166759"> <div class="block-outer"></div> <div class="block-outer js-threadStatusField"></div> <div class="block-container"> <div class="block-body"> <article class="message message--post js-post js-inlineModContainer " data-author="Saeedk9574" data-content="post-1456477" id="js-post-1456477" > <span class="u-anchorTarget" id="post-1456477"></span> <div class="message-inner"> <div class="message-cell message-cell--user"> <section class="message-user" > <div class="message-avatar "> <div class="message-avatar-wrapper"> <a href="/members/saeedk9574.323190/" class="avatar avatar--m avatar--default avatar--default--dynamic" data-user-id="323190" data-xf-init="member-tooltip" style="background-color: #666633; color: #c3c388"> <span class="avatar-u323190-m" role="img" aria-label="Saeedk9574">S</span> </a> </div> </div> <div class="message-userDetails"> <h4 class="message-name"><a href="/members/saeedk9574.323190/" class="username " dir="auto" data-user-id="323190" data-xf-init="member-tooltip">Saeedk9574</a></h4> <h5 class="userTitle message-userTitle" dir="auto">New Member</h5> </div> <span class="message-userArrow"></span> </section> </div> <div class="message-cell message-cell--main"> <div class="message-main js-quickEditTarget"> <header class="message-attribution message-attribution--split"> <ul class="message-attribution-main listInline "> <li class="u-concealed"> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/post-1456477" rel="nofollow" > <time class="u-dt" dir="auto" datetime="2024-10-19T03:26:25-0700" data-time="1729333585" data-date-string="Oct 19, 2024" data-time-string="3:26 AM" title="Oct 19, 2024 at 3:26 AM">Oct 19, 2024</time> </a> </li> </ul> <ul class="message-attribution-opposite message-attribution-opposite--list "> <li> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/post-1456477" class="message-attribution-gadget" data-xf-init="share-tooltip" data-href="/posts/1456477/share" aria-label="Share" rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/post-1456477" rel="nofollow"> #1 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1456477" data-lb-caption-desc="Saeedk9574 · Oct 19, 2024 at 3:26 AM"> <article class="message-body js-selectToQuote"> <div > <div class="bbWrapper">Hi everyone,<br /> <br /> I have some questions about MCU input protection. Although this topic has been discussed many times in this forum and others, I find myself baffled by the differing answers. Thank you in advance for your insights!<br /> <br /> In my project, I will be using both digital input (for a motion detector) and ADC input (for temperature and photocell sensors). First, I would like to know if the protection circuits for digital input and ADC input are different.<br /> <br /> Secondly, which of these circuits is recommended, or is there another circuit you would suggest for protecting both digital and ADC inputs?<br /> <br /> Thanks again for your help!<br /> <br /> <br /> <script class="js-extraPhrases" type="application/json"> { "lightbox_close": "Close", "lightbox_next": "Next", "lightbox_previous": "Previous", "lightbox_error": "The requested content cannot be loaded. 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href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/" class="tabs-tab is-active" rel="nofollow"> Sort by date </a> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/?order=vote_score" class="tabs-tab " rel="nofollow"> Sort by votes </a> </div> </div></div> <div class="block-container lbContainer" data-xf-init="lightbox select-to-quote" data-message-selector=".js-post" data-lb-id="thread-166759" data-lb-universal="0"> <div class="block-body js-replyNewMessageContainer"> <article class="message message--post js-post js-inlineModContainer " data-author="ronsimpson" data-content="post-1456483" id="js-post-1456483" itemscope itemtype="https://schema.org/Answer" itemid="https://www.electro-tech-online.com/posts/1456483/"> <meta itemprop="parentItem" itemscope itemid="https://www.electro-tech-online.com/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/" /> <span class="u-anchorTarget" id="post-1456483"></span> <div class="message-inner"> <div class="message-cell message-cell--user"> <section class="message-user" itemprop="author" itemscope itemtype="https://schema.org/Person" itemid="https://www.electro-tech-online.com/members/ronsimpson.63099/"> <meta itemprop="url" content="https://www.electro-tech-online.com/members/ronsimpson.63099/" /> <div class="message-avatar "> <div class="message-avatar-wrapper"> <a href="/members/ronsimpson.63099/" class="avatar avatar--m" data-user-id="63099" data-xf-init="member-tooltip"> <img src="/data/avatars/m/63/63099.jpg?1378874985" alt="ronsimpson" class="avatar-u63099-m" width="96" height="96" loading="lazy" itemprop="image" /> </a> </div> </div> <div class="message-userDetails"> <h4 class="message-name"><a href="/members/ronsimpson.63099/" class="username " dir="auto" data-user-id="63099" data-xf-init="member-tooltip"><span itemprop="name">ronsimpson</span></a></h4> <h5 class="userTitle message-userTitle" dir="auto" itemprop="jobTitle">Well-Known Member</h5> <div class="userBanner userBanner userBanner--gray message-userBanner" itemprop="jobTitle"><span class="userBanner-before"></span><strong>Most Helpful Member</strong><span class="userBanner-after"></span></div> </div> <span class="message-userArrow"></span> </section> </div> <div class="message-cell message-cell--main"> <div class="message-main js-quickEditTarget"> <header class="message-attribution message-attribution--split"> <ul class="message-attribution-main listInline "> <li class="u-concealed"> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/post-1456483" rel="nofollow" itemprop="url"> <time class="u-dt" dir="auto" datetime="2024-10-19T07:48:59-0700" data-time="1729349339" data-date-string="Oct 19, 2024" data-time-string="7:48 AM" title="Oct 19, 2024 at 7:48 AM" itemprop="datePublished">Oct 19, 2024</time> </a> </li> </ul> <ul class="message-attribution-opposite message-attribution-opposite--list "> <li> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/post-1456483" class="message-attribution-gadget" data-xf-init="share-tooltip" data-href="/posts/1456483/share" aria-label="Share" rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/post-1456483" rel="nofollow"> #2 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1456483" data-lb-caption-desc="ronsimpson · Oct 19, 2024 at 7:48 AM"> <article class="message-body js-selectToQuote"> <div itemprop="text"> <div class="bbWrapper"><b>Bottom</b> schematic. The power of the overvoltage is clamped by a Diode and Zener. The 10 and 1k resistors limit the current. This is good for TTL but not good for analog if the signal voltage is near 4V. Low voltage Zeners will leak current. The knee is soft. You will see errors in the voltage. <br /> <br /> <b>Top</b> schematic. The Zener problem goes away. You can have the input signal in the 0 to 5V range without problems. But now if the power in the overvoltage is too much it will lift the +5V supply. It the wire is connected to +12V it will lift the 5V supply. In this example you will have about 0.5A flowing into the +5V.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" itemtype="https://schema.org/InteractionCounter" itemscope> <meta itemprop="userInteractionCount" content="0" /> <meta itemprop="interactionType" content="https://schema.org/LikeAction" /> </div> <div class="reactionsBar js-reactionsList is-active"> <ul class="reactionSummary"> <li><span class="reaction reaction--small reaction--1" data-reaction-id="1"><i aria-hidden="true"></i><img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="reaction-sprite js-reaction" alt="Like" title="Like" /></span></li> </ul> <span class="u-srOnly">Reactions:</span> <a class="reactionsBar-link" href="/posts/1456483/reactions" data-xf-click="overlay" data-cache="false" rel="nofollow"><bdi>rjenkinsgb</bdi> and <bdi>Diver300</bdi></a> 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<article class="message-body js-selectToQuote"> <div itemprop="text"> <div class="bbWrapper">For 12V inputs, use a resistor divider to reduce the voltage at the device input, before the clamp circuit; never rely on clamping for signals outside the MCU supply voltage.<br /> <br /> eg. A 6.8K in series with the 12V device input and 4.7K from that to 0V, THEN the filter and protection circuit. Also put use a higher value resistor before the clamp diodes, to limit the worst-case clamp current.<br /> <br /> You could use just a 100K series, 0.1uF to 0V, then another 100K in series to the input, for a digital sensor.<br /> That will limit the input current to a negligible value and add noise filtering/debounce, when the sensing speed is not critical.<br /> <br /> Use schmitt trigger input mode on the device.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" itemtype="https://schema.org/InteractionCounter" itemscope> <meta itemprop="userInteractionCount" content="0" /> <meta itemprop="interactionType" content="https://schema.org/LikeAction" /> </div> <div class="reactionsBar js-reactionsList "> </div> <div class="js-historyTarget message-historyTarget toggleTarget" data-href="trigger-href"></div> </footer> </div> </div> <div class="message-cell message-cell--vote"> <div class="message-column"> <div class="contentVote js-contentVote " data-xf-init="content-vote" data-content-id="post-1456503"> <meta itemprop="upvoteCount" content="0" /> <a href="javascript:" class="contentVote-vote is-disabled contentVote-vote--up " data-vote="up"><span class="u-srOnly">Upvote</span></a> <span class="contentVote-score js-voteCount" data-score="0">0</span> <a href="javascript:" class="contentVote-vote is-disabled contentVote-vote--down " data-vote="down"><span class="u-srOnly">Downvote</span></a> </div> </div> </div> </div> </article> <article class="message message--post js-post js-inlineModContainer " data-author="Matthewjtaylor" data-content="post-1458695" id="js-post-1458695" itemscope itemtype="https://schema.org/Answer" itemid="https://www.electro-tech-online.com/posts/1458695/"> <meta itemprop="parentItem" itemscope itemid="https://www.electro-tech-online.com/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/" /> <span class="u-anchorTarget" id="post-1458695"></span> <div class="message-inner"> <div class="message-cell message-cell--user"> <section class="message-user" itemprop="author" itemscope itemtype="https://schema.org/Person" itemid="https://www.electro-tech-online.com/members/matthewjtaylor.328284/"> <meta itemprop="url" content="https://www.electro-tech-online.com/members/matthewjtaylor.328284/" /> <div class="message-avatar "> <div class="message-avatar-wrapper"> <a href="/members/matthewjtaylor.328284/" class="avatar avatar--m avatar--default avatar--default--dynamic" data-user-id="328284" data-xf-init="member-tooltip" style="background-color: #995cd6; 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Although this topic has been discussed many times in this forum and others, I find myself baffled by the differing answers. Thank you in advance for your insights!<br /> <br /> In my project, I will be using both digital input (for a motion detector) and ADC input (for temperature and photocell sensors). First, I would like to know if the protection circuits for digital input and ADC input are different.<br /> <br /> Secondly, which of these circuits is recommended, or is there another circuit you would suggest for protecting both digital and ADC inputs?<br /> <br /> Thanks again for your help!<br /> <br /> just as an MCU input protection circuit safeguards sensitive components from voltage spikes or interference, roofing materials and systems protect a building from environmental elements like rain, wind, and sunlight i know it importance as <a href="https://toituremascouche.ca/" target="_blank" class="link link--external" rel="nofollow ugc noopener">toiture mascouche</a>, for example, in both cases, ensuring the right filtering (like resistors or capacitors in circuits) and shielding (like clamping diodes or roofing underlayment) is critical to prevent damage, whether it’s to a circuit board or the structure of a home.<br /> <a href="https://www.electro-tech-online.com/attachments/147481/" target="_blank">View attachment 147481</a><a href="https://www.electro-tech-online.com/attachments/147482/" target="_blank">View attachment 147482</a> </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote>For both digital and ADC inputs, protection circuits should be tailored to the signal type. For digital inputs, a resistor divider (as suggested by rjenkinsgb) can help reduce voltage before the clamping circuit. For ADC inputs, avoid using low-voltage Zeners, as they can introduce errors, and use a higher-value resistor with low-pass filtering (e.g., 0.1µF). Adding a Schmitt trigger will help improve noise immunity.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" itemtype="https://schema.org/InteractionCounter" itemscope> <meta itemprop="userInteractionCount" content="0" /> <meta itemprop="interactionType" content="https://schema.org/LikeAction" /> </div> <div class="reactionsBar js-reactionsList "> </div> <div class="js-historyTarget message-historyTarget toggleTarget" data-href="trigger-href"></div> </footer> </div> </div> <div class="message-cell message-cell--vote"> <div class="message-column"> <div class="contentVote js-contentVote " data-xf-init="content-vote" data-content-id="post-1458695"> <meta itemprop="upvoteCount" content="0" /> <a href="javascript:" class="contentVote-vote is-disabled contentVote-vote--up " data-vote="up"><span class="u-srOnly">Upvote</span></a> <span class="contentVote-score 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rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/post-1458699" rel="nofollow"> #6 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1458699" data-lb-caption-desc="danadak · Dec 21, 2024 at 4:22 AM"> <article class="message-body js-selectToQuote"> <div itemprop="text"> <div class="bbWrapper">Consult data sheet and application notes for part of choice.<br /> <br /> Simply adding a LPF, specifically a cap, to ADC inputs can affect the sampling<br /> behavior of the ADC input, so arbitrary application of C at input may adversely<br /> affect measurement error, speed.<br /> <br /> Regards, Dana.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" 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Are you sure you want to submit this form?", attach: "Attach files", rich_text_box: "Rich text box", close: "Close", link_copied_to_clipboard: "Link copied to clipboard.", text_copied_to_clipboard: "Text copied to clipboard.", loading: "Loading…", you_have_exceeded_maximum_number_of_selectable_items: "You have exceeded the maximum number of selectable items.", processing: "Processing", 'processing...': "Processing…", showing_x_of_y_items: "Showing {count} of {total} items", showing_all_items: "Showing all items", no_items_to_display: "No items to display", number_button_up: "Increase", number_button_down: "Decrease", push_enable_notification_title: "Push notifications enabled successfully at Electronics Forum (Circuits, Projects and Microcontrollers)", push_enable_notification_body: "Thank you for enabling push notifications!", pull_down_to_refresh: "Pull down to refresh", release_to_refresh: "Release to refresh", refreshing: "Refreshing…" , "svStandardLib_time.day": "{count} day", "svStandardLib_time.days": "{count} days", "svStandardLib_time.hour": "{count} hour", "svStandardLib_time.hours": "{count} hours", "svStandardLib_time.minute": "{count} minutes", "svStandardLib_time.minutes": "{count} minutes", "svStandardLib_time.month": "{count} month", "svStandardLib_time.months": "{count} months", "svStandardLib_time.second": "{count} second", "svStandardLib_time.seconds": "{count} seconds", "svStandardLib_time.week": "time.week", "svStandardLib_time.weeks": "{count} weeks", "svStandardLib_time.year": "{count} year", "svStandardLib_time.years": "{count} years" }); </script> <form style="display:none" hidden="hidden"> <input type="text" name="_xfClientLoadTime" value="" id="_xfClientLoadTime" title="_xfClientLoadTime" tabindex="-1" /> </form>    <div id='div-gpt-eto_wallpaper'> <script> googletag.cmd.push(function() { googletag.display('div-gpt-eto_wallpaper'); }); </script> </div>  <script type="application/ld+json"> { "@context": "https://schema.org", "@type": "QAPage", "url": "https://www.electro-tech-online.com/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/", "mainEntity": { "@type": "Question", "@id": "https://www.electro-tech-online.com/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/", "name": "Choosing the Right Protection for Digital and ADC Inputs", "datePublished": "2024-10-19T10:26:25+00:00", "url": "https://www.electro-tech-online.com/threads/choosing-the-right-protection-for-digital-and-adc-inputs.166759/", "image": "https://www.electro-tech-online.com/attachments/1729333474191-png.147481/", "text": "Hi everyone,\n\nI have some questions about MCU input protection. Although this topic has been discussed many times in this forum and others, I find myself baffled by the differing answers. Thank you in advance for your insights!\n\nIn my project, I will be using both digital input (for a motion detector) and ADC input (for temperature and photocell sensors). First, I would like to know if the protection circuits for digital input and ADC input are different.\n\nSecondly, which of these circuits is recommended, or is there another circuit you would suggest for protecting both digital and ADC inputs?\n\nThanks again for your help!", "answerCount": 5, "upvoteCount": 0, "author": { "@type": "Person", "@id": "https://www.electro-tech-online.com/members/saeedk9574.323190/", "name": "Saeedk9574", "url": "https://www.electro-tech-online.com/members/saeedk9574.323190/" }, "suggestedAnswer": [ { "@type": "Answer", "datePublished": "2024-12-21T12:22:26+00:00", "url": "https://www.electro-tech-online.com/posts/1458699/", "text": "Consult data sheet and application notes for part of choice.\n\nSimply adding a LPF, specifically a cap, to ADC inputs can affect the sampling\nbehavior of the ADC input, so arbitrary application of C at input may adversely\naffect measurement error, speed.\n\nRegards, Dana.", "upvoteCount": 0, "author": { "@type": "Person", "@id": "https://www.electro-tech-online.com/members/danadak.285320/", "name": "danadak", "url": "https://www.electro-tech-online.com/members/danadak.285320/" } }, { "@type": "Answer", "datePublished": "2024-12-21T08:03:03+00:00", "url": "https://www.electro-tech-online.com/posts/1458695/", "text": "Hi everyone,\n\nI have some questions about MCU input protection. Although this topic has been discussed many times in this forum and others, I find myself baffled by the differing answers. Thank you in advance for your insights!\n\nIn my project, I will be using both digital input (for a motion detector) and ADC input (for temperature and photocell sensors). First, I would like to know if the protection circuits for digital input and ADC input are different.\n\nSecondly, which of these circuits is recommended, or is there another circuit you would suggest for protecting both digital and ADC inputs?\n\nThanks again for your help!\n\njust as an MCU input protection circuit safeguards sensitive components from voltage spikes or interference, roofing materials and systems protect a building from environmental elements like rain, wind, and sunlight i know it importance as toiture mascouche, for example, in both cases, ensuring the right filtering (like resistors or capacitors in circuits) and shielding (like clamping diodes or roofing underlayment) is critical to prevent damage, whether it\u2019s to a circuit board or the structure of a home.\n\n\nFor both digital and ADC inputs, protection circuits should be tailored to the signal type. For digital inputs, a resistor divider (as suggested by rjenkinsgb) can help reduce voltage before the clamping circuit. For ADC inputs, avoid using low-voltage Zeners, as they can introduce errors, and use a higher-value resistor with low-pass filtering (e.g., 0.1\u00b5F). Adding a Schmitt trigger will help improve noise immunity.", "upvoteCount": 0, "author": { "@type": "Person", "@id": "https://www.electro-tech-online.com/members/matthewjtaylor.328284/", "name": "Matthewjtaylor", "url": "https://www.electro-tech-online.com/members/matthewjtaylor.328284/" } }, { "@type": "Answer", "datePublished": "2024-10-20T06:14:38+00:00", "url": "https://www.electro-tech-online.com/posts/1456503/", "text": "For 12V inputs, use a resistor divider to reduce the voltage at the device input, before the clamp circuit; never rely on clamping for signals outside the MCU supply voltage.\n\neg. A 6.8K in series with the 12V device input and 4.7K from that to 0V, THEN the filter and protection circuit. Also put use a higher value resistor before the clamp diodes, to limit the worst-case clamp current.\n\nYou could use just a 100K series, 0.1uF to 0V, then another 100K in series to the input, for a digital sensor.\nThat will limit the input current to a negligible value and add noise filtering/debounce, when the sensing speed is not critical.\n\nUse schmitt trigger input mode on the device.", "upvoteCount": 0, "author": { "@type": "Person", "@id": "https://www.electro-tech-online.com/members/rjenkinsgb.273344/", "name": "rjenkinsgb", "url": "https://www.electro-tech-online.com/members/rjenkinsgb.273344/" } } ] }, "publisher": { "@type": "Organization", "name": "Electronics Forum (Circuits, Projects and Microcontrollers)", "description": "An electronics forum to talk all about circuits and projects.", "url": "https://www.electro-tech-online.com" } } </script>  <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-MMC9PJ9" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>   <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-KLX5R59" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>  <script> $(function(){ var notice = $('.xb-welcome-notice'); if(notice.length){ var cookie = XF.Cookie.get('hide_welcome_notice'); if(!cookie){ XF.Cookie.set('hide_welcome_notice', Date.now()); notice.show(); } else if ((Date.now() - cookie) > 8.64e+7){ XF.Cookie.set('hide_welcome_notice', Date.now()); notice.show(); } else { notice.hide(); } } }); </script> </div> </body> </html>

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Choosing the Right Protection for Digital and ADC Inputs | Electronics Forum (Circuits, Projects and Microcontrollers)