Superflux / Piranha 3mm

3mm piranha LEDs (also called 3mm superflux LEDs) are the compact variant of the piranha family, combining the four-lead square body and wide-angle…

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3mm piranha LEDs (also called 3mm superflux LEDs) are the compact variant of the piranha family, combining the four-lead square body and wide-angle light distribution that define all piranha LEDs with a smaller 3mm lens dome that reduces the overall package height. The lower profile makes 3mm piranhas the preferred choice when vertical clearance is tight — inside shallow gauge cluster housings, behind thin control panel overlays, or in slim-profile signage channels where a 5mm dome would interfere with the diffuser panel. Despite the smaller lens, 3mm piranhas still deliver strong brightness (typically 7,000–11,000mcd depending on color) and maintain the wide 100–120° viewing angle that makes the piranha design effective for backlighting applications. We stock 3mm piranha LEDs in every standard color: red, orange, yellow, green, blue, white (warm and cool), pink, UV, and RGB (both common anode and common cathode).

Automotive instrument cluster repair remains the dominant application for 3mm piranha LEDs. Many factory gauge clusters — particularly in GM, Ford, and Toyota vehicles from the late 1990s through the 2010s — use compact LED cavities behind the gauge faces where a full-size 5mm piranha dome would sit too high and create a visible hot spot. The 3mm lens sits lower in the cavity, producing more even backlighting across the gauge face with less risk of bright-spot artifacts. Technicians rebuilding clusters typically replace the entire LED set at once, matching all gauges to the same color for a uniform appearance. Popular color choices include ice blue for a modern look, green to match factory OEM color on older GM trucks, and white for a clean, bright appearance on any vehicle. Beyond gauge clusters, 3mm piranhas are used in HVAC control panel backlighting, radio and infotainment display illumination, seat heater buttons, and other interior dashboard indicators where the LED mounts directly to a PCB inside a compact housing.

Signage and channel letter lighting is the second major market for 3mm piranha LEDs. Illuminated signs, menu boards, and point-of-sale displays use arrays of piranha LEDs behind acrylic or polycarbonate diffuser panels. The 3mm variant allows thinner sign housings without sacrificing even light distribution, since the lower dome height means the LEDs can sit closer to the front panel and still spread light across the full viewing angle. Each LED in the array connects through a current-limiting resistor to the sign’s DC power supply. For large arrays, running multiple LEDs in series through a single higher-value resistor is a common technique — use our LED resistor calculator to determine the correct resistor value for your supply voltage and the combined forward voltage drop of the series string.

RGB piranha LEDs in 3mm add color-mixing capability to the piranha form factor. Like all RGB LEDs, the 3mm RGB piranha contains three separate dies (red, green, blue) inside one package, with four pins: three individual color leads and one common lead (either anode or cathode, depending on the variant you select). By adjusting the current through each channel with PWM from an Arduino, ESP32, or LED driver IC, you can produce any color in the visible spectrum. Common anode 3mm RGB piranhas work naturally with current-sinking LED drivers (TLC5940, PCA9685). Common cathode variants are simpler for direct Arduino GPIO control. Each channel requires its own current-limiting resistor because the red die (2.0–2.2Vf) has a lower forward voltage than the green and blue dies (3.0–3.2Vf).

Mechanical and electrical specifications: 3mm piranha LEDs share the same square body dimensions and 2.54mm pin pitch as all piranha variants — the “3mm” designation refers only to the lens dome diameter, not the body size. The body measures approximately 7.6mm × 7.6mm with four leads at the corners. Forward voltage depends on color: red/orange/yellow/amber runs 2.0–2.2Vf; blue/green/white/UV/pink runs 3.0–3.4Vf. Maximum continuous current is 20mA for all single-color models. The four leads provide excellent mechanical grip on a PCB — once soldered, a piranha LED is extremely difficult to dislodge, which is critical in automotive applications subject to vibration. Thermal performance is also superior to standard two-lead DIP LEDs because heat dissipates through four solder joints instead of two.

Installation tips for gauge cluster work: when desoldering factory LEDs from a cluster PCB, use a solder sucker or desoldering braid to clear the holes cleanly before inserting the new 3mm piranha. Ensure the polarity notch on the piranha body aligns with the PCB silkscreen markings. Solder all four leads, then trim the excess lead length flush with the back of the board to prevent shorts against the cluster housing. Test each LED before reassembling the cluster by applying 12V through the appropriate resistor to confirm it lights up in the correct color. If the factory circuit already has a resistor on the PCB trace (many GM clusters do), verify its value is compatible with the new LED’s forward voltage before relying on it.

If you need higher brightness than the 3mm dome provides, step up to our 5mm piranha LEDs, which offer larger lenses and higher mcd ratings. If you need the lowest possible profile, our flat piranha LEDs eliminate the dome entirely for an ultra-slim package. For projects where you want to skip resistor calculations, our 12V built-in resistor LEDs connect directly to 12V DC with no external components. New to LEDs? Pre-wired LEDs are the easiest starting point — the resistor is already built in, so you just connect power and ground.

Frequently Asked Questions

A 3mm piranha LED is a through-hole LED with a square body, four leads, and a 3mm-diameter lens dome. The “3mm” refers to the lens size, not the body — the body is approximately 7.6mm × 7.6mm, the same as all piranha variants. The four-lead design provides better mechanical stability and thermal dissipation than standard two-lead round LEDs. 3mm piranhas are the lower-profile option in the piranha family, ideal for applications where vertical clearance is limited, such as shallow automotive gauge cluster housings.
Both share the same square body and four-lead pinout. The difference is the lens dome: 3mm piranhas have a smaller dome that sits lower, making them better for tight vertical spaces. 5mm piranhas have a larger dome that captures more light, producing higher brightness ratings (typically 1,000–3,000mcd more than the 3mm equivalent in the same color). Choose 3mm when clearance matters most; choose 5mm when maximum brightness matters most. For the lowest profile of all, our flat piranhas have no dome at all.
Yes — gauge cluster backlighting is the primary use case for 3mm piranha LEDs. The lower profile dome fits shallow cluster cavities without creating hot spots on the gauge face. Desolder the factory LEDs, insert the 3mm piranhas with correct polarity (match the notch to the PCB silkscreen), solder all four leads, and trim flush. Use a current-limiting resistor if the cluster PCB does not already include one on the trace. For a uniform look, replace all gauge LEDs at once in the same color.
The exact resistor value depends on the LED’s forward voltage and your desired drive current. Use our LED resistor calculator — enter your supply voltage (12V for most automotive applications, or 14V to account for alternator charging), the LED’s forward voltage from the product page, and 20mA as the target current. The calculator gives you the exact resistor value and the nearest standard value available.
Yes. We stock 3mm piranha RGB LEDs in both common anode and common cathode configurations. The four pins map to one common lead and three individual color leads (red, green, blue). Each color channel requires its own current-limiting resistor because the red die has a different forward voltage (~2.0V) than the green and blue dies (~3.0V). Drive each channel with PWM from an Arduino or LED driver IC to mix any color in the visible spectrum.
3mm piranha LEDs typically have a viewing angle of 100–120°, which is much wider than standard clear-top round LEDs (15–30°) and comparable to diffused LEDs. This wide angle is what makes piranhas ideal for backlighting — light spreads across a large area behind a gauge face or diffuser panel rather than concentrating in a narrow forward beam. Flat piranhas push the angle even wider, up to 140°.