Everyone knows that capacitors and resistors play a crucial role in LED strips. This article will focus on the resistor calculation guide for 2835 and 5050 LED strips.
The following details how to calculate resistance for standard 2835 and 5050 at 12 V Led Strip and 24 V Led Strip, 60 LEDs/m, 120 LEDs/m, and 240 LEDs/m Led Strip. We can see that varying the number of LEDs also determines the resistance value. The calculation logic for the current-limiting resistor is also explained. Take into account the power, voltage, current per meter, and the ratio of LEDs to resistors within each unit.
This article also uses a 5050 RGB LED light strip as an example. Explain the structure of the three chips within the LEDs and the voltage and resistance design for each red, green, and blue LED. This article not only has the calculation process, but also has pictures, which are practical and easy to use. LED engineers and LED enthusiasts can actually operate according to the steps.
Understanding 2835 and 5050 LEDs：
First, let’s look at the differences between 2835 and 5050 LEDs. While 2835 and 5050 may seem like simple numbers, they actually refer to the size of the LED chip (e.g., 2835: 2.8 mm × 3.5 mm; 5050: 5.0 mm × 5.0 mm).
5050 LEDs: 5050s are larger, have been on the market longer, and are generally less efficient. A 5050 chip typically contains three individual LEDs (typically red, green, and blue in RGB strips). Operating current is typically 20 to 25 mA, so a full-white 5050 LED can consume up to 60 mA.
2835 LEDs: 2835s are arguably more advanced, smaller, and more efficient. Their brightness is comparable to or even higher than that of a 5050, while consuming less power. 2835 LEDs draw a current of approximately 20 to 30 mA.
If you want to know more detailed parameters or pictures of 2835 LED Strip and 5050 LED Strip, you can check out the following link: https://suntechlite.com/led-strip/
If you want to know more about the differences between LED chips, you can also check out our other blog:
1、2835 vs 5050 vs 3838 vs 3535 RGB
This blog explains how to calculate resistor values for common 2835 and 5050 LED strips under 12V and 24V input. We’ll break down power consumption, voltage drops, and current distribution, and include wiring diagrams for better understanding.
Ohm’s Law: V = I × R
Where:
V = Voltage (Volts, V)
I = Current (Amp, A)
R = Resistance (Ohms, Ω)
The answer we need is resistance (R), so the formula becomes:
R = (Power Supply Voltage – LED Operating Voltage) / LED Operating Current
Based on this formula, we can see the following calculation process.
1、2835 LED Strip 60 LEDs/m (DC12V)
Power: 8W/m
Cutting Units: 20 per meter
Each Unit: 3 LEDs + 1 resistor
LED Voltage: 3V per LED
Calculation:
Total voltage: 12V
LED voltage drop: 3V × 3 = 9V
Resistor voltage drop: 12V – 9V = 3V
Total current: 8W / 12V = 666mA
Current per unit: 666mA / 20 = 33mA
Resistor value: 3V / 33mA = 100Ω
Diagram:
2、2835 LED Strip 120 LEDs/m (DC24V)
Power: 14W/m
Cutting Units: 20 per meter
Each Unit: 6 LEDs + 2 resistors
LED Voltage: 3V per LED
Calculation:
LED voltage drop: 3V × 6 = 18V
Resistor voltage drop: 24V – 18V = 6V
Total current: 14W / 24V = 583mA
Current per unit: 583mA / 20 = 30mA
Resistor value: 6V / 30mA/2 = 100Ω
Diagram:
3、2835 LED Strip 240 LEDs/m (DC24V)
Power: 19.2W/m
Cutting Units: 40 per meter
Each Unit: 6 LEDs + 2 resistors
LED Voltage: 3V per LED
Calculation:
LED voltage drop: 3V × 6 = 18V
Resistor voltage drop: 24V – 18V = 6V
Total current: 19.2W / 24V = 800mA
Current per unit: 800mA / 40 = 20mA
Resistor value: 6V / 20mA /2 = 150Ω
Diagram:
4、5050 RGB LED Structure
Each 5050 LED package contains 3 chips (R, G, B) inside one shell.
| Color | Voltage Drop (LEDs) | Resistor Voltage | Current | Resistor Value |
|---|---|---|---|---|
| Red | 6V | 6V | 20mA | 300Ω |
| Green | 9V | 3V | 20mA | 150Ω |
| Blue | 9V | 3V | 20mA | 150Ω |
5、5050 RGB LED Strip 60 LEDs/m (DC12V)
Power: 14.4W/m
Cutting Units: 20 per meter
Each Unit: 3 RGB LEDs + 3 resistors (one per color)
Rated Voltages: Red: 2V, Green/Blue: 3V
Calculation:
Red LED voltage: 2V × 3 = 6V → Resistor voltage: 12V – 6V = 6V
Green/Blue voltage: 3V × 3 = 9V → Resistor voltage: 12V – 9V = 3V
Total current: 14.4W / 12V = 1200mA
Current per unit: 1200mA / 20 = 60mA
Each color draws: 60mA / 3 = 20mA
Resistor value: R:300Ω,G:150Ω,B:150Ω
Diagram:
Please see the table below for a comparison of resistors:
| LED Type | Voltage | LEDs/m | Watts/m | Cut Units/m | LEDs/Unit | Resistor Voltage | Current/Unit | Resistor Value |
|---|---|---|---|---|---|---|---|---|
| 2835 (12V, 60leds) | 12V | 60 | 8W | 20 | 3 | 3V | 33mA | 100Ω |
| 2835 (24V, 120leds) | 24V | 120 | 14W | 20 | 6 | 6V | 30mA | 100Ω |
| 2835 (24V, 240leds) | 24V | 240 | 19.2W | 40 | 6 | 6V | 20mA | 150Ω |
| 5050 RGB (12V, 60) | 12V | 60 | 14.4W | 20 | 3 | 3V/6V | 20mA/color | 150Ω/300Ω |
Based on Ohm’s law and our table, you should now know how to calculate the resistance of an LED strip. We encourage you to practice this calculation. Calculating the resistance of LED strips has many benefits, including: 1. ensuring stable illumination of each LED chip; 2. extending the lifespan of the LED chips; and 3. significantly improving the safety of the strip. Overall, calculating accurate resistance values offers numerous advantages.
If you have any questions about calculations or encounter problems with LED circuit design or resistor selection, please visit our official websites at suntechlite.com. Our professional engineering team can assist you in resolving any issues. Feel free to contact us!
If you want to know more about resistors, you can also check out our other blog: 1206 vs 0805 vs 0603 vs 0402 Resistor in LED Strip