What Is a COB LED Strip Light? How It Works and Why It’s Different

A standard LED strip shows a dotted runway of bright spots with dim gaps. COB — chip on board — mounts a dense array of chips directly on the circuit board under a phosphor coating. That coating diffuses each chip’s output into its neighbors, so the strip reads as one even ribbon of light. For under-cabinet runs, shelves, and anywhere the strip stays visible, that smoothness is the draw.

How Does a COB LED Strip Light Actually Work?

COB strips place a tight row of LED chips on the PCB, then a phosphor layer spreads their light into a seamless band. A conventional SMD strip has distinct emitters, so each shows as a hotspot; COB packs them so closely that no single chip stands out.

Density explains the smoothness. Datasheets list COB strips at 300 LED/m, 480 LEDs/m, 528 LEDs/m, and up to 546 LED chips per meter. Barthelme’s led strip basic cob runs 546 chips per meter with a 170° beam angle; Lyyt’s Seamless COB strip packs 528 LEDs per meter at 2 mm spacing and a 180° beam angle; Adafruit’s COB strip lists 480 LEDs/m and 180°.

Wider angles and tighter spacing make the output look continuous — a 160° to 180° spread matters most when the strip sits close to what it’s lighting.

Voltage is a separate decision. Most datasheets call for 24V DC (Barthelme, QLT, and the IP-12730 model); Adafruit’s strip is 12V DC, and some COB products run 5V DC. Dimming works on many COB models, but only with a compatible driver or controller — QLT’s sheet names PWM, 0–10V, DALI, and DMX support.

Why COB Strips Look Different From Standard LED Tape

The difference is point sources versus a continuous emitter: SMD tape shows every LED as a bright dot, while COB hides the chips behind the phosphor layer so the strip produces one unbroken line.

CRI ratings on COB datasheets cluster at 90 or higher, keeping colors natural. Efficiency varies widely — the Barthelme strip produces 1350 lm/m at 2700K and 1400 lm/m at 3000K at 18 W/m; QLT’s IP65 model lands at 910 to 970 lm/m at 12 W/m; the IP-12730 hits 1000 lm/m ±10% at 10 W/m. Higher wattage doesn’t automatically mean better light, so check lumens-per-watt on the exact model.

Each strip on that list is a different product with a different job. To compare specific models side by side, our roundup of tested COB LED strip light options breaks down how they stack up for real installations.

What To Check Before You Buy Or Cut A COB Strip

Four specs decide whether a COB strip works in your project: voltage, IP rating, cut length, and driver compatibility.

Voltage must match the driver exactly. A 24V DC strip on a 12V supply is underdriven; the reverse can damage the strip. Cut points are model-specific: Barthelme marks 38.5 mm, Lyyt 4.5 cm, and the IP-12730 a 5 cm module length. Cutting anywhere else kills the section past the cut.

The IP rating decides where the strip can live. IP20 versions, including the Lyyt model and Barthelme’s IP00 strip, are indoor, dry-location products only. For damp or outdoor runs, look at sealed versions like QLT’s IP65 or the IP-12730 at IP66.

Dimming needs a compatible driver, not just any dimmer — check the datasheet for the protocol your controller uses. Fine references for exact figures are the Farnell LED datasheet collection, which documents model-level specs, cut lengths, and dimming support.

Don’t assume every COB strip is sealed, dimmable, or interchangeable. The category spans 5V to 24V, IP00 to IP66, and densities from 300 to 546 chips per meter. Reading the exact model’s sheet takes two minutes and prevents most installation mistakes.