{"id":3634,"date":"2026-10-03T14:00:00","date_gmt":"2026-10-03T14:00:00","guid":{"rendered":"https:\/\/onpowbutton.com\/news\/ac-vs-dc-indicator-light\/"},"modified":"2026-10-06T09:12:22","modified_gmt":"2026-10-06T09:12:22","slug":"ac-vs-dc-indicator-light","status":"publish","type":"post","link":"https:\/\/onpowbutton.com\/es\/news\/ac-vs-dc-indicator-light\/","title":{"rendered":"AC vs DC Indicator Lights: Matching the Panel Supply"},"content":{"rendered":"<style>@media(max-width:767px){.onpow-backfill-article{box-sizing:border-box!important;padding-right:28px!important;max-width:100%!important;}}<\/style>\n<div class=\"onpow-backfill-article\">\n<p>An AC indicator light must be selected for its declared AC supply conditions; a DC indicator light must match its declared DC voltage range and any polarity requirements. The same nominal voltage number does not make the two versions interchangeable. A complete panel lamp may include rectification, current limiting, or another internal circuit, so its rating must come from the exact model and suffix. Do not connect a bare LED as if it were a rated panel indicator, and do not assume an AC-only lamp can operate correctly on DC. Confirm supply, terminals, signal source, and environment together.<\/p>\n<nav aria-label=\"Contents\"><strong>Contents<\/strong><\/p>\n<ul>\n<li><a href=\"#identify-the-supply-at-the-lamp-s-actual-connection\">Identify the supply at the lamp&#8217;s actual connection<\/a><\/li>\n<li><a href=\"#read-the-complete-rating-and-suffix\">Read the complete rating and suffix<\/a><\/li>\n<li><a href=\"#a-bare-led-and-a-complete-panel-lamp-are-different-devices\">A bare LED and a complete panel lamp are different devices<\/a><\/li>\n<li><a href=\"#ac-voltage-notation-does-not-describe-a-dc-operating-point\">AC voltage notation does not describe a DC operating point<\/a><\/li>\n<li><a href=\"#verify-polarity-from-the-manufacturer-s-drawing\">Verify polarity from the manufacturer&#8217;s drawing<\/a><\/li>\n<li><a href=\"#check-compatibility-with-electronic-outputs\">Check compatibility with electronic outputs<\/a><\/li>\n<li><a href=\"#specify-what-the-light-is-meant-to-prove\">Specify what the light is meant to prove<\/a><\/li>\n<li><a href=\"#environment-and-mounting-remain-part-of-the-decision\">Environment and mounting remain part of the decision<\/a><\/li>\n<li><a href=\"#verify-safely-and-record-the-approved-variant\">Verify safely and record the approved variant<\/a><\/li>\n<li><a href=\"#frequently-asked-questions\">Frequently asked questions<\/a><\/li>\n<\/ul>\n<\/nav>\n<h2 id=\"identify-the-supply-at-the-lamp-s-actual-connection\">Identify the supply at the lamp&#8217;s actual connection<\/h2>\n<p>Start with the circuit drawing and identify where the lamp receives power. The machine can contain mains AC, a control transformer, a DC power supply, and electronic outputs. The cabinet&#8217;s incoming supply does not necessarily match the indicator circuit.<\/p>\n<p>Record the intended nominal voltage, allowed variation, AC frequency where relevant, and whether the signal is switched by a relay contact, transistor output, or another device. A measured value without its circuit context can be misleading. Use qualified personnel and the equipment&#8217;s approved electrical-work procedure for any measurement.<\/p>\n<p>For voltage-specific questions, the <a href=\"https:\/\/onpowbutton.com\/news\/12v-vs-24v-led-indicator-lights\/\">12V versus 24V indicator-light guide<\/a> and <a href=\"https:\/\/onpowbutton.com\/news\/120v-ac-indicator-light\/\">120V AC indicator-light guide<\/a> provide related selection contexts. This article addresses the distinction between supply types rather than choosing one nominal voltage for every panel.<\/p>\n<h2 id=\"read-the-complete-rating-and-suffix\">Read the complete rating and suffix<\/h2>\n<p>A product family can include several voltage and circuit variants with the same front appearance. The full order code should identify the required supply version. Keep the current product data, label, and purchase record together so that a familiar lens color does not become the basis for substitution.<\/p>\n<p>An AC rating may state a frequency or operating range. A DC version may specify polarity or particular terminal connections. A dual-rated product must explicitly declare both capabilities. Do not infer a dual rating from two terminals, a similar body, or a seller&#8217;s generic family photograph.<\/p>\n<div aria-label=\"Article comparison table\" role=\"region\" style=\"overflow-x:auto!important;max-width:100%!important;width:100%!important;display:block!important\" tabindex=\"0\">\n<table style=\"min-width:600px!important;width:100%!important;border-collapse:collapse\">\n<thead>\n<tr>\n<th>Selection question<\/th>\n<th>AC variant<\/th>\n<th>DC variant<\/th>\n<th>Dual-rated variant<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Supply match<\/td>\n<td>Confirm stated AC voltage and frequency conditions<\/td>\n<td>Confirm stated DC voltage and allowed range<\/td>\n<td>Confirm both declared ranges and conditions<\/td>\n<\/tr>\n<tr>\n<td>Terminal connection<\/td>\n<td>Use the exact installation drawing<\/td>\n<td>Check declared polarity and terminal map<\/td>\n<td>Follow the declared terminal requirements<\/td>\n<\/tr>\n<tr>\n<td>Output interface<\/td>\n<td>Check switching device and load compatibility<\/td>\n<td>Check output type, reference, leakage, and current<\/td>\n<td>Verify suitability for the actual circuit used<\/td>\n<\/tr>\n<tr>\n<td>Replacement record<\/td>\n<td>Preserve full AC variant code<\/td>\n<td>Preserve full DC variant code<\/td>\n<td>Preserve full dual-rated variant code<\/td>\n<\/tr>\n<tr>\n<td>Missing data<\/td>\n<td>Do not assume DC compatibility<\/td>\n<td>Do not assume AC compatibility<\/td>\n<td>Do not describe a product as dual-rated without evidence<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>The table is a purchasing method, not a statement that every ONPOW model is offered in all three forms.<\/p>\n<figure><img decoding=\"async\" alt=\"ONPOW indicator light reference example for ac vs dc indicator lights: matching the panel supply, component detail\" loading=\"lazy\" src=\"https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-body1.webp\" style=\"width:100%;height:auto\" title=\"AC vs DC Indicator Lights: Matching the Panel Supply \u2014 body1\"\/><figcaption>Reference-based illustration of an ONPOW indicator light example. Confirm the exact variant drawing and ratings before specifying the application.<\/figcaption><\/figure>\n<h2 id=\"a-bare-led-and-a-complete-panel-lamp-are-different-devices\">A bare LED and a complete panel lamp are different devices<\/h2>\n<p>A bare LED is a semiconductor light source that requires an appropriately designed electrical circuit. Its behavior does not directly describe a complete industrial indicator. A panel device can package one or more LEDs with circuitry and a mounting structure intended for a declared supply.<\/p>\n<p>The complete device&#8217;s documentation should state how it is connected. Adding an external resistor to a panel lamp without checking its internal circuit can change brightness and operation. Conversely, applying a panel-supply voltage directly to a bare LED can damage it. Identify which type of device is actually being specified.<\/p>\n<p>If a replacement has different internal circuitry, review its current, input behavior, and compatibility with the switching output. A lamp that lights on a bench once has not been qualified for the equipment&#8217;s supply range or environment.<\/p>\n<h2 id=\"ac-voltage-notation-does-not-describe-a-dc-operating-point\">AC voltage notation does not describe a DC operating point<\/h2>\n<p>AC and DC ratings represent different operating conditions. A numerical AC voltage commonly refers to an RMS value in the stated context; it is not a declaration that a product accepts the same number as a steady DC voltage. Internal rectification and current-limiting arrangements can make the differences important.<\/p>\n<p>Do not determine compatibility by converting one supply number with a generic formula. The complete lamp&#8217;s circuit and declared operating range govern. If the data sheet does not state DC use, obtain written clarification or choose a documented DC variant.<\/p>\n<p>For the standards context, <a href=\"https:\/\/webstore.iec.ch\/en\/publication\/65935\" rel=\"noopener\" target=\"_blank\">IEC 60947-5-1<\/a> covers relevant electromechanical control-circuit devices and signalling equipment. Its published scope is not a substitute for an individual indicator&#8217;s AC\/DC rating, current, or installation instructions.<\/p>\n<h2 id=\"verify-polarity-from-the-manufacturer-s-drawing\">Verify polarity from the manufacturer&#8217;s drawing<\/h2>\n<p>Some DC indicators require a defined positive and negative connection. Others may have a documented internal arrangement that permits a different connection convention. Do not generalize either case to all products in the same family.<\/p>\n<p>Use terminal labels and the exact diagram. Wire color is a helpful installation record but not proof of terminal polarity. If a lamp does not illuminate after installation, do not reverse wires repeatedly or apply a higher voltage as an experiment. Check the ordered variant, supply condition, terminal map, and signal source through the approved diagnostic process.<\/p>\n<p>A symbol on the schematic also does not establish the complete panel lamp&#8217;s internal circuit. The <a href=\"https:\/\/onpowbutton.com\/news\/indicator-light-vs-illuminated-push-button\/\">indicator versus illuminated push-button guide<\/a> explains why the lamp function and operator contacts may need separate electrical records.<\/p>\n<h2 id=\"check-compatibility-with-electronic-outputs\">Check compatibility with electronic outputs<\/h2>\n<p>A controller&#8217;s transistor output has an electrical interface that differs from a dry relay contact. Review its sourcing or sinking arrangement, voltage range, available current, residual voltage, and leakage specifications. Compare those with the indicator&#8217;s input requirements.<\/p>\n<p>A small leakage current can make certain lamps glow when the output is nominally off. That observation does not necessarily mean the lamp is the wrong AC\/DC type, but the complete circuit needs review. Do not add an arbitrary shunt resistor or change a supply without the output and lamp manufacturers&#8217; permitted design information.<\/p>\n<p>The <a href=\"https:\/\/onpowbutton.com\/news\/indicator-light-leakage-current\/\">indicator-light leakage-current guide<\/a> addresses this separate issue. Keep unwanted off-state glow distinct from a wrong supply variant, reversed polarity, or failed controller output when diagnosing a panel.<\/p>\n<h2 id=\"specify-what-the-light-is-meant-to-prove\">Specify what the light is meant to prove<\/h2>\n<p>A power indicator can show the presence of a particular control supply, but it may not indicate every source of energy in the cabinet. A run indicator may follow a command, feedback contact, drive status, or measured condition. Its label should identify the intended meaning.<\/p>\n<p>Do not use a dark indicator as proof that equipment is electrically isolated. The lamp can fail, a conductor can open, or another supply can remain energized. The required verification of an electrical condition belongs to the appropriate work procedure and instruments, not an assumed interpretation of a panel lens.<\/p>\n<p>Use the <a href=\"https:\/\/onpowbutton.com\/news\/industrial-indicator-light-colors\/\">industrial indicator-light color guide<\/a> for visual communication. Color and supply type answer different design questions and should be documented separately.<\/p>\n<figure><img decoding=\"async\" alt=\"ONPOW indicator light reference example for ac vs dc indicator lights: matching the panel supply, installation planning\" loading=\"lazy\" src=\"https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-body2.webp\" style=\"width:100%;height:auto\" title=\"AC vs DC Indicator Lights: Matching the Panel Supply \u2014 body2\"\/><figcaption>Reference-based illustration of an ONPOW indicator light example. Confirm the exact variant drawing and ratings before specifying the application.<\/figcaption><\/figure>\n<h2 id=\"environment-and-mounting-remain-part-of-the-decision\">Environment and mounting remain part of the decision<\/h2>\n<p>Check ambient conditions, enclosure space, front-panel mounting, rear clearance, terminals, and the complete installation&#8217;s exposure. A dual-rated electrical circuit does not establish ingress protection, chemical resistance, or suitability for an outdoor panel.<\/p>\n<p>Heat and service access can matter in a crowded cabinet. Use the exact product&#8217;s declared conditions and mounting instructions. A substitute with a different body length can fit the same cutout but interfere with cable routing or nearby components.<\/p>\n<p>The illustrations use a real <a href=\"https:\/\/onpowbutton.com\/ad16-22d-product\/\">ONPOW AD16-22D product reference<\/a>. They show physical form, not proof that the pictured variant accepts both AC and DC. Request the current order-code table and electrical data for the desired supply before ordering.<\/p>\n<h2 id=\"verify-safely-and-record-the-approved-variant\">Verify safely and record the approved variant<\/h2>\n<p>Electrical inspection and work must be performed by qualified personnel following the applicable procedure. For United States workplaces, <a href=\"https:\/\/www.ecfr.gov\/current\/title-29\/section-1910.333\" rel=\"noopener\" target=\"_blank\">29 CFR 1910.333<\/a> addresses relevant work practices. Where machine servicing involves hazardous energy, <a href=\"https:\/\/www.ecfr.gov\/current\/title-29\/section-1910.147\" rel=\"noopener\" target=\"_blank\">29 CFR 1910.147<\/a> provides additional context. Apply the rules relevant to the actual work.<\/p>\n<p>A document review should confirm supply, variant, terminal map, output interface, and intended indication before connection. During authorized commissioning, verify the on-state, off-state, brightness at the relevant viewing conditions, and the defined source signal. Use the engineering plan for any supply-range or fault-response test.<\/p>\n<p>Record the full part number, drawing revision, supply, output reference, and results. Mark an unresolved rating as pending rather than inheriting another model&#8217;s data. A future replacement should preserve the approved electrical variant as carefully as the mounting dimensions and lens color.<\/p>\n<h2 id=\"educational-video\">Educational video<\/h2>\n<div style=\"position:relative;padding-bottom:56.25%;height:0;overflow:hidden\"><iframe allowfullscreen=\"\" loading=\"lazy\" src=\"https:\/\/www.youtube-nocookie.com\/embed\/1LTlVFSXkSI\" style=\"position:absolute;inset:0;width:100%;height:100%;border:0\" title=\"PLC Stack Light Logic\"><\/iframe><\/div>\n<p>PLC Stack Light Logic by Instrumentation Tools. General educational background. Use the selected product drawing and the machine design for the actual circuit and installation. <a href=\"https:\/\/www.youtube.com\/watch?v=1LTlVFSXkSI\" rel=\"noopener\" target=\"_blank\">Watch on YouTube<\/a>.<\/p>\n<h2 id=\"frequently-asked-questions\">Frequently asked questions<\/h2>\n<h3>Can an AC indicator lamp run on DC at the same voltage?<\/h3>\n<p>Only if the exact product declares that use. Matching voltage numbers alone do not establish compatibility.<\/p>\n<h3>Does every DC indicator need correct polarity?<\/h3>\n<p>Check the manufacturer&#8217;s drawing. Some require defined polarity and others have a documented different arrangement; neither rule can be assumed for every panel lamp.<\/p>\n<h3>Is a two-terminal lamp automatically dual-rated?<\/h3>\n<p>No. Terminal count does not identify the internal circuit or permitted supply. Obtain the exact variant&#8217;s declared rating.<\/p>\n<h3>Can a dark power lamp prove that a cabinet is isolated?<\/h3>\n<p>No. The lamp or its circuit can fail and other energy sources can remain present. Follow the required isolation and verification procedure.<\/p>\n<h3>What information should be sent to ONPOW?<\/h3>\n<p>Provide supply type and range, AC frequency if applicable, switching-output reference, intended signal meaning, mounting requirements, environment, and the existing part code.<\/p>\n<p><script type=\"application\/ld+json\">{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"Can an AC indicator lamp run on DC at the same voltage?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Only if the exact product declares that use. Matching voltage numbers alone do not establish compatibility.\"}}, {\"@type\": \"Question\", \"name\": \"Does every DC indicator need correct polarity?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Check the manufacturer's drawing. Some require defined polarity and others have a documented different arrangement; neither rule can be assumed for every panel lamp.\"}}, {\"@type\": \"Question\", \"name\": \"Is a two-terminal lamp automatically dual-rated?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No. Terminal count does not identify the internal circuit or permitted supply. Obtain the exact variant's declared rating.\"}}, {\"@type\": \"Question\", \"name\": \"Can a dark power lamp prove that a cabinet is isolated?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No. The lamp or its circuit can fail and other energy sources can remain present. Follow the required isolation and verification procedure.\"}}, {\"@type\": \"Question\", \"name\": \"What information should be sent to ONPOW?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Provide supply type and range, AC frequency if applicable, switching-output reference, intended signal meaning, mounting requirements, environment, and the existing part code.\"}}]}<\/script><\/div>","protected":false},"excerpt":{"rendered":"<p>Match a panel indicator to its declared AC or DC supply. Check exact variants, polarity, electronic outputs, leakage and the intended signal.<\/p>","protected":false},"author":6,"featured_media":3610,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-3634","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"uagb_featured_image_src":{"full":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature.webp",1536,1024,false],"thumbnail":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature-150x150.webp",150,150,true],"medium":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature-300x200.webp",300,200,true],"medium_large":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature-768x512.webp",768,512,true],"large":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature-1024x683.webp",1024,683,true],"1536x1536":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature.webp",1536,1024,false],"2048x2048":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature.webp",1536,1024,false],"trp-custom-language-flag":["https:\/\/onpowbutton.com\/wp-content\/uploads\/2026\/10\/onpow-backfill-ac-vs-dc-indicator-light-feature-18x12.webp",18,12,true]},"uagb_author_info":{"display_name":"Turbo","author_link":"https:\/\/onpowbutton.com\/es\/author\/turbo\/"},"uagb_comment_info":0,"uagb_excerpt":"Match a panel indicator to its declared AC or DC supply. Check exact variants, polarity, electronic outputs, leakage and the intended signal.","_links":{"self":[{"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/posts\/3634","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/comments?post=3634"}],"version-history":[{"count":3,"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/posts\/3634\/revisions"}],"predecessor-version":[{"id":3679,"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/posts\/3634\/revisions\/3679"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/media\/3610"}],"wp:attachment":[{"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/media?parent=3634"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/categories?post=3634"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/onpowbutton.com\/es\/wp-json\/wp\/v2\/tags?post=3634"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}