Bicolor LED Wiring: 2-Pin and 3-Pin Types Explained
Quick answer: 2-pin bicolor LEDs light red with current one way and green the other way; 3-pin bicolor LEDs have two dies sharing a common pin — identify the type first, then wire accordingly with one resistor per color path.
Type 1: 2-Pin (Inverse-Parallel)
- Two dies wired anti-parallel inside one package.
- Current A→B lights color 1; B→A lights color 2.
- Drive from two MCU pins, or from AC/alternating drive for both colors (yellow mix).
- One resistor is enough because only one die conducts at a time.
Type 2: 3-Pin (Common Anode or Common Cathode)
- Longest center lead is the common pin; outer leads are one color each.
- Common cathode: common pin to GND, drive each anode high through its own resistor.
- Common anode: common pin to V+, pull each cathode low through its own resistor.
- Both colors can be on at once — always use a separate resistor per die.
How to Tell Which Type You Have
Count the leads. For 3-pin parts, test with diode mode: common-anode conducts from the common pin to each outer pin. The pinout drawing in the datasheet settles it definitively.
Resistor Sizing
Size each color separately — red (2.0 V) and green (2.2 V) need slightly different values for equal brightness: R = (Vs - Vf)/If per die.
Need datasheets, samples or a bulk quote? Browse our LED datasheet center or product center. Bi-color options: SMD and through-hole series. Hongcheng Optoelectronics, a member of Guangyu Group, has 20+ years of LED packaging experience with A-grade chips and 99.99% pure gold wire bonding.
