Tools & Accessories
LED Blue
৳2
Standard 5 mm blue LED with a forward voltage around 3.2V — noticeably higher than red or green, so it wants roughly a 100Ω resistor on 5V.
Blue and white LEDs use a different semiconductor to the older colours, which is why the forward voltage jumps and why the same 220Ω resistor leaves them looking dim.
What you can build
- Modern-looking status and accent lighting
- Indicators that need to stand out from red and green
- Display backlighting
Not sure it will work? Test your circuit free in Tekko Sim — on your phone, in Bangla or English.
| Category | Tools & Accessories |
| Model no. | 5mm blue |
| Availability | In stock |
| In stock | 25 pcs |
| Delivery | Cash on Delivery, nationwide Bangladesh |
| Colour | blue |
| Size | 5 mm through-hole |
| Forward Voltage | roughly 3.0–3.4V |
| Forward Current | 20 mA typical |
| Suggested Resistor on 5V | 100Ω |
| Polarity | long leg is the anode, positive |
| Note | forward voltage is too high to run reliably from 3.3V |
Questions about the LED Blue
Why is my blue LED dim with a 220Ω resistor?
Because blue needs around 3.2V, leaving only about 1.8V across the resistor on a 5V rail — that is roughly 8 mA instead of 20. Drop to 100Ω and it brightens right up. This is the most common surprise when swapping a red LED for a blue one.
Can I run a blue LED from 3.3V?
Barely, and not reliably. The forward voltage is close to 3.3V, leaving almost no headroom for a resistor, so brightness varies wildly with the supply. Run blue LEDs from 5V.
Which leg is positive?
The longer leg is the anode, and the flat notch on the rim marks the negative cathode.
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