--- title: How to measure the output of a constant voltage LED driver description: Learn how to read an LED driver label so you can find the right replacement when a driver fails. image: https://insights.regencysupply.com/hubfs/LED-Driver-CV.png --- - [Corporate](https://www.regencysupply.com/) - [Shop](https://shop.regencysupply.com/) - [Studio](https://rl.studio/) [Login/Signup](https://shop.regencysupply.com/b2b/portal/login/) [![Regency Supply Logo](https://regencysupply.com/wp-content/uploads/rs-logo-r-2.svg)](https://regencysupply.com/) Menu - [Search Site](https://www.regencysupply.com/searching/) - [Shop Products](https://shop.regencysupply.com/) - [Services](https://www.regencysupply.com/services/) - [Architectural Lighting Design](https://www.regencysupply.com/services/architectural-lighting-design/) - [Lighting Supply](https://www.regencysupply.com/services/lighting-supply/) - [Electrical Supply](https://www.regencysupply.com/services/electrical-supply/) - [Construction Services](https://www.regencysupply.com/services/construction-supplier/) - [Lighting Retrofits](https://www.regencysupply.com/services/lighting-retrofits/) - [Lighting Maintenance](https://www.regencysupply.com/services/maintenance/) - [Product Lines](https://www.regencysupply.com/lighting-solutions-and-services/product-lines/) - [Client Success Stories](https://www.regencysupply.com/lighting-solutions-and-services/client-success-stories/) - [Resources](https://www.regencysupply.com/lighting-resources/) - [About Us](https://www.regencysupply.com/about-regency-lighting/) - [Leadership](https://www.regencysupply.com/about-regency-lighting/leadership-team/) - [Evan Regenstreif](https://www.regencysupply.com/about-regency-lighting/leadership-team/evan-regenstreif/) - [Isaac Regenstreif](https://www.regencysupply.com/about-regency-lighting/leadership-team/isaac-regenstreif/) - [Judah Regenstreif](https://www.regencysupply.com/about-regency-lighting/leadership-team/judah-regenstreif/) - [Scott Anderson](https://www.regencysupply.com/about-regency-lighting/leadership-team/scott-anderson/) - [Hoon Kim](https://www.regencysupply.com/about-regency-lighting/leadership-team/hoon-kim/) - [Ron Regenstreif](https://www.regencysupply.com/about-regency-lighting/leadership-team/ron-regenstreif/) - [Mike Goldstone](https://www.regencysupply.com/about-regency-lighting/leadership-team/mike-goldstone/) - [Careers](https://www.regencysupply.com/about-regency-lighting/careers/) - [Regency Supply News](https://news.regencysupply.com/) - [Event And Social Photos](https://www.regencysupply.com/about-regency-lighting/event-and-social-photos/) - [Contact Us](https://www.regencysupply.com/contact-us/) - [Credit Application](https://www.regencysupply.com/contact-us/credit-application-for-lighting-services/) - [Apply For Tax Exemption](https://app.certcapture.com/logins/login) - [Office Locations](https://www.regencysupply.com/contact-us/#rl-locations) - [Search](https://www.regencysupply.com/searching/) - [Store Login](https://shop.regencysupply.com/) ### REGENCY INSIGHTS BLOG Practical advice on commercial lighting from LED retrofts to lighting design [ Back to blog home](https://insights.regencysupply.com) [View all posts  ](https://insights.regencysupply.com/all) ![](https://insights.regencysupply.com/hubfs/LED-Driver-CV.png) # How to measure the output of a constant voltage LED driver Posted by [Andrew Thomas](https://insights.regencysupply.com/author/andrew-thomas) on February 5, 2025 ![print](https://www.regencysupply.com/rl-custom/printer.png "Print this page") [![Share on Facebook](https://insights.regencysupply.com/hubfs/Icons/icon-facebook.svg)](http://www.facebook.com/share.php?u=https%3A%2F%2Finsights.regencysupply.com%2Fhow-to-measure-constant-voltage-led-driver-output%3Futm_medium%3Dsocial%26utm_source%3Dfacebook) [![Share on LinkedIn](https://insights.regencysupply.com/hubfs/Icons/icon-linkedin.svg)](http://www.linkedin.com/shareArticle?mini=true&url=https%3A%2F%2Finsights.regencysupply.com%2Fhow-to-measure-constant-voltage-led-driver-output%3Futm_medium%3Dsocial%26utm_source%3Dlinkedin) [![Share on Twitter](https://insights.regencysupply.com/hubfs/Icons/icon-x.svg)](https://twitter.com/intent/tweet?original_referer=https%3A%2F%2Finsights.regencysupply.com%2Fhow-to-measure-constant-voltage-led-driver-output%3Futm_medium%3Dsocial%26utm_source%3Dtwitter&url=https%3A%2F%2Finsights.regencysupply.com%2Fhow-to-measure-constant-voltage-led-driver-output%3Futm_medium%3Dsocial%26utm_source%3Dtwitter&source=tweetbutton&text=How%20to%20measure%20the%20output%20of%20a%20constant%20voltage%20LED%20driver) [![Share on Pinterest](https://insights.regencysupply.com/hubfs/Icons/icon-pinterest.svg)](http://pinterest.com/pin/create/button/?url=https%3A%2F%2Finsights.regencysupply.com%2Fhow-to-measure-constant-voltage-led-driver-output%3Futm_medium%3Dsocial%26utm_source%3Dpinterest&media=http%3A%2F%2Fcdn1.hubspot.com%2Fhub%2F158015%2F305390_10100548508246879_837195_59275782_6882128_n.jpg) [![Share on Email](https://insights.regencysupply.com/hubfs/Icons/icon-mail.svg)](mailto:?subject=Check%20out%20https%3A%2F%2Finsights.regencysupply.com%2Fhow-to-measure-constant-voltage-led-driver-output%3Futm_medium%3Dsocial%26utm_source%3Demail%20&body=Check%20out%20https%3A%2F%2Finsights.regencysupply.com%2Fhow-to-measure-constant-voltage-led-driver-output%3Futm_medium%3Dsocial%26utm_source%3Demail) WRITTEN BY A HUMAN   Constant voltage LED drivers are less common than constant current drivers, but they are still used in many commercial applications. You'll generally see these when you're powering a configurable run of LEDs like tape light, rope light, or some configurable linear systems.  When you're replacing one of these drivers, your key specifications to consider are the output voltage and total system wattage, but what happens if you don't know the output voltage for your existing driver? If a driver label is damaged or you have a programmable driver and don't know the output settings, this article will help you measure the output of your constant voltage LED driver. If you're reading this, you probably have a good sense that you're working with a constant voltage driver, but if you're not sure what kind of LED driver you have, check out these resources:  - [What are the types of LED drivers?](https://insights.regencysupply.com/what-are-the-types-of-led-drivers) - [How to read an LED driver label](https://insights.regencysupply.com/how-to-read-led-driver-label) It's also worth noting that this test requires a working driver, so if you are replacing a driver that has already failed, you can do this measurement on another working fixture in your facility.  We're including detailed instructions below, but you can also check out our explainer video:  ## Tools needed to test your LED driver Before you begin, you'll need these tools to test the output of your driver. - **Multimeter:** Use a [quality multimeter](https://shop.regencysupply.com/digital-multimeter-trms-auto-ranging-1000v-includes-temperature-probe-klein-mm720-mm720.html) that will measure DC voltage.  - **Wire connectors:** You can use any type of wire connector, but we've found that [Wago Lever Lock wire connectors](https://shop.regencysupply.com/catalogsearch/result/?q=wago%20lever) are safe, quick, and easy for doing tests like this.  - **Other tools:** You may also need tools (screwdriver, etc.) to open your fixture and get access to the driver. ⚠️ Safety note! This may seem obvious, but safety is important. Turn off power to any light fixtures before you begin working on them and be sure to use appropriate personal protective equipment. ## Step 1: Configure your meter to read DC voltage The first step to measuring the amperage output of your driver is to set up your [multimeter](https://shop.regencysupply.com/digital-multimeter-trms-auto-ranging-1000v-includes-temperature-probe-klein-mm720-mm720.html) properly. You'll want to make sure your testing leads are plugged into the correct ports (they should be labeled COM and V), that the dial or mode selector is measuring voltage, and that your meter is set to read DC. It will probably look similar to this:  ![CV-Driver-Meter](https://insights.regencysupply.com/hs-fs/hubfs/CV-Driver-Meter.png?width=839&height=629&name=CV-Driver-Meter.png) ## Step 2: Connect your meter in parallel to the LED driver output To measure output amperage, you'll need to connect the meter *in parallel* with the output of the LED driver.  You'll need to identify the two wires supplying power to the LED board (typically red and black). Connect the red lead of the meter to the (+) output of the driver and the black lead of the meter to the (−) output of the driver.    If the driver has screw terminals for the wiring connections, you can touch your meter leads to the appropriate +/− terminals on the driver without disconnecting any wires. If you don't have access to screw terminals, your connections may look similar to this: ![CV-Driver-Wiring](https://insights.regencysupply.com/hs-fs/hubfs/CV-Driver-Wiring.png?width=839&height=629&name=CV-Driver-Wiring.png) ## Step 3: Turn on power to the fixture Now that your meter is set up and you're connected in series with the driver and LEDs, you can turn on power to the fixture.  In our example, we have an LED driver for configurable light modules that produces a constant 24VDC output: ![CV-Driver-Output](https://insights.regencysupply.com/hs-fs/hubfs/CV-Driver-Output.png?width=839&height=629&name=CV-Driver-Output.png) This means we can replace this with a constant current driver rated for 24VDC that is rated for at least the amount of wattage as the connected LED modules. As an example, if you have 50W of tape light being supplied by a 12VDC constant voltage driver, your replacement constant voltage driver must be configured to produce 12VDC and must be rated for at least 50W.  ## Finding a replacement constant voltage driver for your LED fixture Drivers are hard. The technical secs can be confusing, and it's essential to get the details right so you don't damage your fixture. So, it's okay if you feel stuck finding a replacement constant voltage driver or you're still not 100% sure what type of driver you need. Here are some resources to help:  If you're trying to read an LED driver label or take note of the output from your testing, don't forget to use our [guide](https://info.regencysupply.com/led-driver-guide) to record your specifications. Then head over to our [Replacement LED Driver Wizard](https://www.regencysupply.com/resources/led-driver-wizard-2/) to get replacement recommendations.  And if you need a helping hand, our team is [always here to help](https://www.regencysupply.com/contact-us/).  [![CTA-LEDDRG-B – 1](https://insights.regencysupply.com/hs-fs/hubfs/Call-to-Action_Images/CTA-LEDDRG-B%20%E2%80%93%201.png?width=600&height=233&name=CTA-LEDDRG-B%20%E2%80%93%201.png)](https://info.regencysupply.com/led-driver-guide)   [![](https://www.regencylighting.com/rl-custom/images/search-posts-graphic.svg)](https://www.regencysupply.com/searching/) Keep up with our latest updates [Subscribe Now](https://info.regencysupply.com/en-us/lighting-blog-signup) [![Get your business account](https://no-cache.hubspot.com/cta/default/455757/da04c52a-287d-4340-ab12-055921e93293.png)](https://cta-redirect.hubspot.com/cta/redirect/455757/da04c52a-287d-4340-ab12-055921e93293) [![Get your free lighting review](https://no-cache.hubspot.com/cta/default/455757/ef6d50f0-0bdc-4896-8156-a7d2b0415c92.png)](https://cta-redirect.hubspot.com/cta/redirect/455757/ef6d50f0-0bdc-4896-8156-a7d2b0415c92) #### Related Posts [![](https://insights.regencysupply.com/hubfs/LED-Driver-CC.png) How to measure the output of a constant current LED driver](https://insights.regencysupply.com/how-to-measure-constant-current-led-driver-output) [![](https://insights.regencysupply.com/hubfs/LED-Driver-Types.jpg) What are the types of LED drivers?](https://insights.regencysupply.com/what-are-the-types-of-led-drivers) [![](https://insights.regencysupply.com/hubfs/LED-Driver-Labels.jpg) How to read an LED driver label](https://insights.regencysupply.com/how-to-read-led-driver-label) [![](https://insights.regencysupply.com/hubfs/What-to-do-about-the-fluorescent-bulb-bans.png) What should I do about the fluorescent bulb bans?](https://insights.regencysupply.com/what-to-do-about-fluorescent-bulb-bans) [![](https://insights.regencysupply.com/hubfs/Blog_Images/UTD-HID-LED-retrofit.jpg) UT Dallas retrofits from HID to LED in arena to boost performance and controllability](https://insights.regencysupply.com/ut-dallas-goes-from-hid-to-led-in-arena-to-boost-performance-and-controllability) [![](https://insights.regencysupply.com/hubfs/Blog_Images/dummy-load-resistor-led-dimming-flickering-stop.jpg) Can you stop LED flickering with a "dummy load" or load resistor?](https://insights.regencysupply.com/can-you-stop-led-flickering-with-a-dummy-load-or-load-resistor) View all posts   #### Related Topics [LED](https://insights.regencysupply.com/topic/led) [LED Drivers](https://insights.regencysupply.com/topic/led-drivers) #### Popular Topics [LED Lighting](https://insights.regencysupply.com/topic/led) [Product Comparison](https://insights.regencysupply.com/topic/product-comparison) [Lighting Controls](https://insights.regencysupply.com/topic/lighting-controls) [Lighting as a Service](https://insights.regencysupply.com/topic/lighting-as-a-service) [Energy Savings](https://insights.regencysupply.com/topic/energy-savings) [Title 24](https://insights.regencysupply.com/topic/title-24) [Technology](https://insights.regencysupply.com/topic/lighting-technology) [Indoor Air Quality](https://insights.regencysupply.com/topic/indoor-air-quality) [Cleaning & Disinfection](https://insights.regencysupply.com/topic/cleaning-disinfection) [FAQs](https://insights.regencysupply.com/topic/faqs) [Lighting Maintenance](https://insights.regencysupply.com/topic/lighting-maintenance) [Lighting 101](https://insights.regencysupply.com/topic/lighting-101) [![](https://www.regencysupply.com/rl-custom/images/search-posts-graphic.svg)](https://www.regencysupply.com/searching/) Keep up with our latest updates [Subscribe Now](https://info.regencysupply.com/en-us/lighting-blog-signup) HQ 9261 Jordan Avenue Chatsworth, CA 91311 **Phone:** [+1-800-284-2024](tel:+18002842024) **[Send us a message.](http://www.regencysupply.com/contact-us/contact-us/)** **[Find a location.](https://www.regencysupply.com/contact-us/#RS-locations)** Family owned and operated since 1983 [![](https://www.regencysupply.com/wp-content/uploads/rs-main-badge-w.svg)](https://insights.regencysupply.com/newname) What's the story with our rebrand? [Learn more.](https://www.regencysupply.com/newname) [![RSS](https://www.regencysupply.com/wp-includes/images/rss.png)](https://insights.regencysupply.com/rss.xml) [Lighting Insights](https://insights.regencysupply.com/) - [4 reasons lighting causes developers' schedules to fall behind on construction projects](https://insights.regencysupply.com/4-reasons-lighting-causes-developers-schedules-to-fall-behind-on-construction-projects) Aug 1, 2022 - [What is DLC v5.1 and how does it impact my lighting purchase?](https://insights.regencysupply.com/what-is-dlc-5.1) Jul 26, 2022 - [Trends in pricing and quality in LED lighting](https://insights.regencysupply.com/trends-in-pricing-and-quality-in-led-lighting) Jul 19, 2022 - [California's light bulb ban](https://insights.regencysupply.com/california-light-bulb-ban) Jul 13, 2022 - [Is there an incandescent light bulb ban?](https://insights.regencysupply.com/was-there-actually-an-incandescent-light-bulb-ban) Jul 11, 2022 - [A state by state look at light bulb bans \[Interactive map\]](https://insights.regencysupply.com/state-light-bulb-bans) Jul 6, 2022 #### Looking for products? [View Product Lines](https://www.regencysupply.com/lighting-solutions-and-services/product-lines/) [Shop our Store](https://shop.regencysupply.com/) © Regency Supply, All Rights Reserved. - [RL Studio](https://rl.studio) - [Shop Lighting](https://shop.regencysupply.com/) - [Branding](https://www.regencysupply.com/branding/) - [Privacy Policy](https://www.regencysupply.com/privacy-policy/) - [Site Map](https://www.regencysupply.com/site-map/) ![](https://secure.deng3rada.com/216972.png) ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Andrew Thomas", "url" : "https://insights.regencysupply.com/author/andrew-thomas" }, "dateModified" : "2025-02-05T13:30:00.549Z", "datePublished" : "2025-02-05T13:30:00.000Z", "headline" : "How to measure the output of a constant voltage LED driver", "image" : [ "https://insights.regencysupply.com/hubfs/LED-Driver-CV.png" ], "mainEntityOfPage" : { "@id" : "https://insights.regencysupply.com/how-to-measure-constant-voltage-led-driver-output", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://insights.regencysupply.com/hubfs/RS-Logo-R-1.png" }, "name" : "Regency Supply" } } ```