The operation voltage of the two-color LED KY-011 is between 2V and 2.5V. Therefore we need a resistor in series for the red and green light input to reduce the output voltage on our micocontroller. We will use 330Ω resistors for the Arduino with an operation voltage of 5V and 100Ω resistors for ESP8266 and ESP32 microcontroller with an Unfortunately they often come in SMD packages, which can be complicated to work with. The example project: Ambient light activated lamp - 5050 LED strip Edition. The operating conditions: The power supply voltage is . U SYS = 12V typical. The LEDs are a 2m long 5050 LED strip with 120LEDs . I LED = 0.8A; The logic signal voltage is . U IO = 5V Show activity on this post. The forward voltage is the voltage drop across the diode (LEDs) if the voltage at the anode is more positive than the voltage at the cathode (if you connect + to the anode). It is not a fixed value. Coming back to LEDs, the brightness of an LED depends on the amount of current passing through it, which is a function For the first time I want to include some SMD LED (0603) vom LCSC. However, I am not sure about the choice of resistors. Of course, I did my homework and looked up the forward voltage and the corresponding current and calculated the required resistor value for 3.3 V supply voltage. However, compared to other PCBs desings I saw, the values seem Assume the LED will have a forward drop of around 1V (could be less, could be more). Start with 1mA of forward current and go from there. ILED = 12V − 1V 1mA = 11kΩ I L E D = 12 V − 1 V 1 m A = 11 k Ω. Then, install the resistor in series with the LED, apply power, and measure the battery voltage and the resistor voltage to actually Step 1: The Pinout. One of the most annoying part of these little gems is the lack of a pinout diagram that was useful. While looking at the photo, you will notice that the four pins are three different lengths. Also there is a flat side of the housing on the left side. amtra5. • 6 yr. ago. You won't be able to use the WS2812 LEDs due to their size and power consumption. Each WS2812 uses 18mA, and USB 2.0 has a power draw limit of 500mA. Instead, you'll have to use RGB LEDs without an integrated controller and wire them up in a matrix to a dedicated LED driver. In addition, you'll have to write much of the 10v supply. If you have established that you want to put 300mA into the disk, and you know that the VFwd is going to be (in the vicinity of) 3 x 3.3 = 9.9. Known: Current through the resistor = 0.3A. Voltage over the resistor = 10 - 9.9 = 0.1. So it follows by Ohm's law: Resistor = 0.1v / 0.3A = 0.33' Ohms. Logged. You mentioned running from 3.3V. With a FET, the voltage drop across the FET will be Rds * current. With 0.05 Ohm (50 milliohm) FET and 60 mA of current, that will be just .003V, so you have 3.297 to go across your LED & resistor. With a 3.2V Vf diode, that could be enough to drive it. \$\begingroup\$ LED strips usually use multiples of 3 LEDs plus a resistor across 12v. So IF each LED drew 60 mA you'd get 60 mA x 12V per 3 LEDS or 6A for 300. BUT a 5050 pkg in a LED strip probably has 3 x individual LEDS in the pkg rated at 20 m each or 60 mA the 3 in parallel or 20 mA in series. Which gives the answer I gave. Nkio.