How to choose F3/F5 (3mm/5mm) direct insertion LED indicator beads? Round head, straw hat, flat head, concave, matte, transparent, all explained in one go

For device indicator lights, direct insertion of LED is still the first choice for many engineers: it can be installed without opening steel mesh, manual welding, good directionality, and low cost. But there are various forms of direct insertion light beads - round head, straw hat, flat head, concave, matte, transparent - choosing the wrong form, only to find it "too dazzling" or "not visible from the side" when installed on the panel.

This article compiles the most commonly asked questions when providing selection support to customers on a daily basis at Hongcheng Optoelectronics into a comparative guide.

1、 First, determine the size: 3mm or 5mm

One sentence: Choose 3mm for small panel openings, 5mm for conventional equipment, and 8mm/10mm for visible openings every few meters.

2、 Re shaping: The shape of the head determines the direction of light

Round head (ball head)The emission angle is usually 20 ° -60 °, and the light is concentrated forward with strong directionality. Suitable for status indication facing the observer, such as power lights and running lights. For scenes that require "seeing from a distance at a glance", choose the ball head spotlight model.

Flat head (flat top)The emission angle can reach 90 ° -120 °, and the light is evenly dispersed. A panel indicator suitable for close range and multi angle viewing, which can also be seen from the side.

Grass hat (helmet)Large angle (120 ° -160 °) scattering, low front brightness but overall uniformity, commonly used for light strings, decorative lighting, and low-cost indicators.

concaveThe luminous surface is concave, taking into account both focusing and a certain angle, with a soft light spot. It is commonly used in instrument panels and situations that require soft and high brightness indicators.

3、 Final decision on colloid: matte or transparent

This is the most commonly overlooked but visually impactful indicator light selection:

• Transparent adhesiveSpotlight, strong penetration, bright when viewed from the front, but glaring at close range, and rapid attenuation of brightness on the side. Suitable for remote indication and scenes that require the use of dark panels.
• Foggy surface (milky white diffusion) colloidThe light is uniformly scattered by diffusing particles, and the entire colloid emits light uniformly without being dazzling, with consistent brightness from any angle. For occasions such as control cabinets, operation panels, and charging stations where people come close to observe, it is recommended to choose a matte finish.
• Colored colloids (red to red, green to green)When the lights are turned off, colors can be distinguished. The panel with multiple lights arranged side by side prevents installation errors, but sacrifices about 10% -20% of brightness.

4、 Don't forget to check the electrical parameters

Conventional electrical specifications for direct insertion indicator lights:

• Red, yellow, orange, and green: forward voltage 1.8-2.2V, 20mA drive
• Blue, pure green, white: forward voltage 2.8-3.4V, 20mA drive
• When low voltage red and high voltage pure green are mixed, the current limiting resistor must be calculated separately

The 5V system drives a single red light: R=(5-2.0)/0.02 ≈ 150 Ω; drives blue/white lights: R=(5-3.2)/0.02 ≈ 91 Ω (taken as 100 Ω).

5、 Frequently Asked Questions (FAQ)

Q: Is the pin spacing between 3mm and 5mm LED beads the same?

Similarly, the standard foot spacing is 2.54mm and can be directly replaced (pay attention to whether the shape matches the panel opening).

Q: Can I customize the lighting angle and foot length?

Okay. Our direct insertion series supports customization of angles (15 ° -160 °), foot lengths (long and short feet, bent foot forming), and gel colors. Standard stock items are available for standard shapes.

Q: How long does the indicator light decay after use?

The lamp beads packaged with regular chips and gold wires can control the light attenuation within 3% after 1000 hours under 20mA rated drive. The actual lifespan largely depends on the driving current and heat dissipation - long-term use of overcurrent is the primary cause of dead lights.

6、 Summary

Three steps for selecting direct insertion indicator lights:Size (3mm/5mm) → Shape (Round head spotlight/Flat head large angle/Straw hat scattering/Concave soft light) → Colloid (Transparent spotlight/Uniform matte surface)After three steps of determining the voltage and current, it is unlikely to overturn.

Hongcheng Optoelectronics' 3mm/5mm direct insertion indicator beads cover the full forms of round head, straw hat, flat head, and concave, with complete transparent/matte/colored colloids. Standard products are available in both red and green colors, as well as red, yellow, and green colors, and support free sample testing. If you need specifications or samples, please feel free to contact: 139 2571 4318 (same WeChat account), sales@led-hc.com .