How to Use a 3mm LED Diode Mixed 5 Colour Kit

Quick answer

To use a 3mm LED diode mixed 5 colour kit, identify polarity (longer leg is positive), choose the right resistor using an LED resistor calculator, and wire them in series or parallel on a breadboard.

Step-by-step guide

1. Identify polarity: Each LED has two legs: the longer one is the anode (positive), the shorter is the cathode (negative). Also, the cathode side of the LED body is usually flat. A common mistake is to assume all LEDs have the same leg length; always check individually. Use a multimeter in diode mode or a simple coin cell to test polarity if unsure.
2. Choose the resistor: Use an LED resistor calculator: input your supply voltage (e.g., 5V), LED forward voltage (approx. 2V for red/green/yellow, 3V for blue/white), and desired current (20 mA). The calculator will output the resistor value (e.g., 150 ohms). A common mistake is using a resistor that is too small, risking LED burnout. Always round up to the next standard resistor value if the exact value isn't available.
3. Wire on a breadboard: Connect the resistor to the anode leg of the LED, then connect the resistor's other end to the positive terminal of your power source. Connect the cathode leg to the negative terminal. For multiple LEDs, wire them in parallel with individual resistors. A common mistake is wiring LEDs in series without adjusting resistor values, which can cause uneven brightness. Test each LED individually before assembling the full circuit.

Product facts

• 3mm Led Diode Mixed 5 Colour x 100each -500pcs: 3mm Led Diode Mixed 5 Colour x 100each -500pcs This kit gives you 500 LEDs in five colors, enough for multiple breadboard prototypes or learning projects without buying separate packs.