3535 Dual-Band UVC + UVA LED Bead - 275nm Germicidal + 395nm Indicator (5-7V)

Specifications:

• Package: 3535 SMD (3.5mm x 3.5mm) Ceramic Base
• Wavelength 1 (Sterilization): 270nm - 280nm (Peak 275nm UVC)
• Wavelength 2 (Indicator): 395nm - 400nm (Visible UVA Purple)
• Forward Voltage (Vf): 5.0V - 7.0V (Dual Series Internal) 
• Forward Current (If): 40mA - 100mA (Recommended 60mA)
• Radiant Flux (UVC): 2mW - 5mW (Standard for 3535)
• Beam Angle: 120 Degrees (Quartz Glass Lens)
• Lifespan: 10,000 Hours (UVC degrades faster than standard LEDs)

Key Applications & Projects

• Portable Sterilizers: DIY sanitizing wands for keyboards, masks, and parcels.
• Water Purification: Embedding into bottle caps or small tanks (requires quartz window).
• Surface Disinfection: Automated rovers that scan and clean countertops.
• Horticulture Research: Experiments on UV stress response in plants.
• Bio-Safety Cabinets: Low-cost sterilization for maker biology labs.

Project Evolution 

• Past Projects: Using "Blacklight" strips hoping they kill germs (they don't).
• Feature Upgrade: This component brings Medical-Grade Physics to your workbench. By designing a simple 555 timer circuit or using an Arduino, you can create a "Smart Sanitizer" that activates for 60 seconds when a lid is closed, ensuring dosage without exposure.
• Effort Level: Intermediate. Requires reflow soldering (SMD component) or careful hand soldering to a PCB star.

Virtual Technician & Wiring

• BIO-HAZARD WARNING: 275nm UVC is Carcinogenic and damaging to eyes/skin. It causes DNA damage. NEVER expose eyes or skin. Enclose your project in a box with a safety interlock switch.

   

• Thermal Management: Despite the small size, UVC efficiency is low (<5%), meaning 95% of power becomes heat. You MUST solder this to an Aluminum PCB (Star Board) for cooling.

• Driving: Probots™ Logic-Safe ⚡ Rule: This is a sensitive semiconductor. Use a Constant Current source (e.g., LM317 set to 60mA). Do not use a simple resistor on a fluctuating voltage source.

• Soldering: Requires Reflow Oven or Hot Plate (260°C max for 3 sec). Hand soldering is difficult due to the ceramic base heat sink.

​Packages include:

1 X 3535 Dual-Band UVC + UVA LED Bead - 275nm Germicidal + 395nm Indicator (5-7V)

Frequently Asked Questions (FAQ)

1. Does this actually kill viruses?
   Yes, 275nm UVC effectively destroys the DNA/RNA of bacteria and viruses, preventing replication. Effectiveness depends on distance and time.
2. Why does it glow purple if UVC is invisible?
   That is the secondary 395nm chip. It is added intentionally so you know the device is ON. Without it, you wouldn't see the UVC.
3. Can I power this with a 9V battery?
   Yes, but you need a driver or appropriate resistor to drop the voltage to ~6V and limit current to 60mA.
4. Is it safe to look at?
   NO. Even brief exposure can cause "welder's flash" (painful eye irritation). Long exposure causes cataracts.
5. What voltage do I use?
   Typically 5.0V - 7.0V. Test with a constant current supply starting low.
6. Can I solder wires directly to the bead?
   No. It is a tiny SMD part with pads on the bottom. You must reflow it onto a PCB.
7. Does it generate ozone?
   No. 275nm does not generate ozone. Ozone is generated by <240nm (Vacuum UV).
8. How long does it take to sterilize?
   At 2cm distance, typical kill time for surface bacteria is 30-60 seconds.
9. Will it fade plastic?
   Yes, UVC is very aggressive and will degrade plastics/rubbers rapidly.
10. Is the lens glass or plastic?
    It is Quartz Glass. Regular plastic/glass blocks UVC, so Quartz is required.
11. Can I use it for resin curing?
    It works poorly for curing. Use the 405nm LEDs for that. This is for germs.
12. Why is it more expensive than blue LEDs?
    UVC chips use AlGaN substrates which are difficult to grow and manufacture.
13. Is it waterproof?
    The bead itself is hermetic, but your connections are not.
14. Can I use it in an aquarium?
    Yes, for water sterilization inside a filter. Do not shine directly on fish.
15. Is it Probots™ Lab Verified ?
    Yes, verified for peak emission at 275nm.
16. How much current?
    Max 100mA, but 60mA is best for lifespan.
17. Can I use a 5V USB supply?
    Maybe not directly. If Vf is 6V, 5V won't light it. You might need a boost module.
18. Does it get hot?
    Yes, for its size. It needs a heatsink PCB.
19. What is the radiant power?
    Approx 2-5mW of UVC energy. This is standard for low-cost 3535 chips.
20. Can I test it with a banana?
    You can test it on a banana peel; UVC will turn the peel brown/black in the exposed area overnight (oxidation).