3mm Diffused Flat Top LED

3mm diffused flat-top LEDs combine a colored translucent lens with a flat, flush-mounted top surface in a compact 3mm (T-1) through-hole package.

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3mm diffused flat-top LEDs combine a colored translucent lens with a flat, flush-mounted top surface in a compact 3mm (T-1) through-hole package. Unlike the standard domed round-top shape, the flat-top LED sits level with the panel surface when mounted, creating a clean, professional flush appearance. The flat emitting surface also distributes light more evenly across the upper hemisphere — there is no dome to focus or redirect light, so the viewing angle is wide (typically 100–130°) and the illumination is exceptionally uniform. The colored lens tint matches the emitter color, providing at-a-glance identification even when the LED is unpowered. This combination of flush mounting, wide diffusion, and compact 3mm size makes the 3mm diffused flat-top ideal for tight-space indicator panels, guitar pedal status lights, miniature model electronics, and custom control interfaces.

Flush-mount panel indicators: The primary advantage of a flat-top LED over a round-top is the mounting profile. When installed in a panel hole or LED holder, the flat top sits level with the panel surface instead of protruding above it. This creates a sleek, integrated appearance used in professional audio equipment, test instruments, rack-mount gear, and custom electronics enclosures. The 3mm flat-top is particularly popular in dense panel layouts where multiple indicators are tightly spaced — the flat surface prevents adjacent LED domes from overlapping visually. Guitar pedal builders who want a flush indicator light rather than a protruding dome use 3mm flat-tops in standard 3mm bezels for a clean, modern pedal face. The flat surface also resists accidental bumps better than a dome — important for pedals that get stepped on during live performance.

Model railroad signals and electronics: Model railroaders building custom signal heads, control panels, and dispatcher boards use 3mm diffused flat-top LEDs where the flat surface produces a more realistic signal face than a dome. Scale signal lamps are flat — they do not have a domed protrusion — so a flat-top LED more closely replicates the prototype appearance. The diffused lens ensures the signal light is visible from wide angles around the layout table. Red, green, and amber are the standard North American signaling colors. HO scale modelers also use 3mm flat-tops for flush-mounted locomotive number board lights and classification lamp indicators.

Wargaming, props, and small-scale builds: Miniature wargaming hobbyists use 3mm diffused flat-tops in builds where the LED is surface-mounted on a base, terrain piece, or vehicle model and needs to sit flush rather than protrude. The flat top prevents the LED from snagging on terrain features during gameplay and provides a more integrated look. Prop builders use 3mm flat-tops in costume electronics, gauntlet displays, and handheld device replicas where a flush panel indicator is more realistic than a domed one. The 3mm body fits into tight spaces inside 28mm scale models and compact prop housings.

Flat top vs. round top — when to choose each: Flat-top and round-top LEDs are electrically identical — same forward voltage, same current, same resistor values. The choice is entirely about the physical profile and light distribution. Flat-tops produce a wider, more uniform light spread and sit flush with a panel surface. Round-tops protrude slightly above the panel and produce a visible dome that some builders prefer for decorative or traditional indicator looks. If your build requires a flush panel surface or you need the widest possible light distribution in a 3mm package, choose flat-top. If you want the classic domed indicator look, choose 3mm diffused round-top. For the same flat-top shape with a neutral milky white lens, see our 3mm diffused flat-top frosted LEDs.

Colors, wavelengths, and electrical specifications: Available in red, orange, amber, yellow, green, blue, warm white, cool white, and pink. Each product page lists the peak emission wavelength in nanometers. Forward voltage by color: red/orange/yellow/amber ≈ 2.0–2.2V; blue/green/white/UV ≈ 3.0–3.2V. Maximum forward current: 20mA. A current-limiting resistor is required in series with every bare LED. Use our LED resistor calculator to find the correct value for your supply voltage, or check the resistor table on each product page. The 3mm body fits a 3.2mm (1/8″) panel-mount hole. The longer lead is the anode (+); the shorter lead is the cathode (−).

Power sources and related categories: For AC model railroad transformers, DCC track voltage, or 12V AC landscape wire, add a bridge rectifier and smoothing capacitor to convert to clean DC. See the AC/DCC wiring guide. If you need the flat-top profile with a neutral milky lens, see our 3mm diffused flat-top frosted LEDs. For a larger flat-top indicator, browse 5mm diffused flat-top LEDs. For maximum on-axis brightness, clear-top 3mm flat-top LEDs focus light into a tighter beam. For automatic blinking effects, see animated LEDs. New to LEDs? Pre-wired LEDs include the resistor on the wire.

A flat-top LED has a flat, flush upper surface instead of the traditional rounded dome. When installed in a panel, it sits level with the surface rather than protruding above it. The flat surface distributes light more evenly across the upper hemisphere, producing wider, more uniform illumination. Electrically, flat-top and round-top LEDs are identical — same forward voltage, same 20mA max current, same resistor requirements.
Typically 100–130°. The flat emitting surface spreads light more evenly across the upper hemisphere than a domed lens, and the diffused tint further scatters the output. The result is a wide, uniform glow visible from most viewing positions above the LED plane. The exact angle varies by color and is listed on each product page.
The resistor value depends on your supply voltage and LED color, not the lens shape. A flat-top LED uses the same resistor as a round-top LED of the same color. Use our LED resistor calculator for the exact value, or check the product page resistor table. New to LEDs? Pre-wired LEDs include the resistor on the wire — just connect power and ground.
Yes. The body diameter is the standard 3mm, so flat-top LEDs fit the same 3mm LED holders, bezels, and 3.2mm (1/8″) panel holes as round-top 3mm LEDs. The only difference is that the top sits flush instead of protruding as a dome.
Both work well. Flat-top LEDs sit flush with the pedal enclosure for a sleek, modern look and resist accidental bumps from foot traffic. Round-top LEDs protrude slightly and produce the traditional domed indicator appearance. It is purely a cosmetic and physical preference — electrically they are identical. Many boutique pedal builders prefer flat-top for a cleaner design aesthetic.
LEDs require DC power. For DCC track voltage or AC transformers, add a bridge rectifier and smoothing capacitor to convert to clean DC. See our AC/DCC wiring guide for a complete wiring diagram.