Prewired 12V 3mm UV LEDs are small, ready-to-install ultraviolet indicator lamps sold in a 30-piece set. Each diode is mounted behind a clear 3mm lens and comes with a preloaded resistor and insulated lead wires, making them convenient for quick wiring into low-voltage DC circuits without extra resistor selection or soldering to bare LEDs.
What these LEDs are — quick technical snapshot
This pack includes 30 prewired 3mm UV light-emitting diodes intended for DC 12V systems. Key parameters supplied by the manufacturer include:
- Prewired with resistor: Each LED has a 1/4W metal film resistor already attached to suit DC 12V operation.
- Wire leads: 7.8 inch lead length, 7-core pure copper with tinned ends for easier soldering or connector insertion.
- Polarity colors: Anode is purple, cathode is black for straightforward identification.
- Electrical: Forward voltage: DC 12V; forward current: 20mA.
- Optics: 3mm clear lens with a 30° viewing angle.
- Quantity and life: 30 pieces per set and a rated lifespan of 20,000+ hours.
Key features in context
- Preloaded resistor simplifies hookups. Because a 1/4W metal-film resistor is already included, you can plug these into a 12V DC source without calculating and wiring a separate resistor in series. That saves time on prototyping and reduces wiring mistakes.
- Long, tinned leads for flexibility. The 7.8 inch lead length gives reach for panel mounting, small enclosures, or breadboard-to-board wiring. Tinned ends improve solderability and compatibility with crimp or screw terminals.
- Narrow beam and small lens. With a 30° viewing angle and a clear 3mm lens, these LEDs produce a focused UV spot rather than a wide wash of light. That makes them useful where directed illumination is desired.
- Durability expectation. The rated lifespan of over 20,000 hours indicates they’re meant for prolonged hobby or decorative use under appropriate operating conditions.
Polarity, connectors and mounting tips
Each diode’s leads are color-coded: the anode uses a purple wire and the cathode uses a black wire. Match the anode to positive 12V and the cathode to ground when connecting. Because leads are pre-tinned, they will accept quick solder joints or can be placed into small screw terminals or breadboard jumpers.
Electrical requirements and what the built-in resistor means
These LEDs are specified for DC 12V operation at about 20mA forward current. The included 1/4W metal-film resistor is chosen to limit current at 12V so you do not need an external dropping resistor in most simple installations. Avoid applying voltages significantly higher than 12V, and keep wiring secure to prevent short circuits that could bypass the resistor.
Practical uses and project ideas
- DIY electronics: Use them as indicator lights on custom control panels, status indicators on hobby boards, or visual cues in microcontroller projects where UV is needed.
- Decoration and props: Their small size and narrow beam make them suitable for accent lighting in scale models, art projects, or themed displays requiring ultraviolet tones.
- Instructional demonstrations: Handy for classroom experiments where a controlled UV source is needed to show fluorescence with safe samples.
- Multiple small installations: A 30-piece set enables distributed placement—multiple indicators, strings, or modular panels—while keeping wiring uniform thanks to the prewired leads.
If you need a curing lamp for nail gels, consider pairing these diodes with a compatible unit such as the Mini Flash Cure Lamp: Mini Flash Cure Lamp
Limitations and suitability
These diodes are compact 3mm devices with a clear lens and a 30° beam. They are intended for low-current, low-voltage applications and are not substitutes for high-power UV curing lamps or lamps that require a broad, high-intensity ultraviolet field. The prewired resistor is matched to 12V; altering the supply voltage or removing the resistor will change current and could damage the diode.
Safety and handling notes
- Avoid direct eye exposure: Even small UV LEDs can be harmful to eyes with prolonged direct viewing. Use shields or indirect viewing when experimenting.
- Respect polarity and insulation: Wire colors denote anode (purple) and cathode (black); confirm connections before powering to prevent reverse-biasing the diode.
- Heat and enclosure: While these are low-power parts, install them where heat can dissipate and where the prewired connections won’t be pinched or abraded.
Buying notes and price
The set is offered as a 30-piece kit. At the time of writing the set lists for USD 8.99; prices may change.
Conclusion
For hobbyists and small-scale electronics makers, this 30-piece pack of prewired 12V 3mm UV LEDs provides an easy-to-use UV source with built-in current limiting, long tinned leads, and standardized polarity coloring. They are best applied to indicator roles, accent lighting, and educational demonstrations rather than as replacements for high-power curing equipment. Use proper handling and appropriate enclosures to get reliable, long-lived performance from the kit.