If you need multiple LEDs on the same circuit, you can share a resistor and wire the LEDs in series. This changes the resistor calculation a little. For example, with two LEDs off 12V you get (12-2-2)=8V across the resistor instead of (12-2)=10V, so for 20mA you would need 400 ohms instead of 500 (say 470 instead of 560 using real values). Step 3: Test the turn after the wires are tapped. If the turn signal still hyper flashes, take the wires out and tap it to another wire and try again. The most times you will try to tap the wires is three times. We are going to assign each wire with a letter for easier reference: Red-A, Green-B, and Black-C. I know leds need resistors or at least with the through hole leds I've been working with. Now I'm looking to upgrade but most are smd type. Are they… LED driver boards are extra helpers that make working with LEDs easier. SparkFun has several boards customized for different LEDs and different applications. Some, like the Lumidrive, connect to a computer over USB so you can control the LEDs directly from your computer. Others, such as the FemtoBuck, enable a low-current microcontroller to Update: It was suggested that the resistors are in parallel, and that the normal 5630 leds take 150 mA @ 3.4V. That may be true. (12V Source Voltage - (3 Leds * 3.4V)) / 13.5 Ohms = 0.150 Amps (150 mA) Only way to be sure would be to trace the circuit and measure the current or voltages with a multimeter. Share. Firstly, either apply the three LEDs in series, with one resistor in series, or if you must have them in parallel, each will need a series resistor. simulate this circuit. The above indicative values of resistors are assuming 20 mA per LED as optimal. Do your own calculations for your specific LEDs. Detail: 330 ohms may be used by some people as a "get you going" value that works "well enough" in many cases. The purpose of the resistor is to "drop" voltage that is not required to operate the LED, when the LED is operating at the desired current. As the forward voltage of LEDs varies both with colour and chemistry used and with current, and as the " The stated specs are nominal, typical figures, and there will be variations. One LED may be 10mA at 1.9 VF, but another may be 8 or 12 mA or different at the same VF. That's not even taking brightness into account. Two leds with the same IV curve can be noticeably different in color and brightness too. You also have to account for your supply's The schematic diagram above contains two LEDs, two NPN transistors, two non-polarized capacitors, and four resistors. The two 47k resistors and the capacitance of C1 and C2 determine the charging time of the two capacitors, while the two 470 Ohm resistors are there to limit the current flowing through each LED. 5eZYM.

do smd leds need resistors