![]() ![]() Voltage differences can always be measured across components, e.g. Voltage is the potential difference between two points in a circuit. The current flow direction you have shown correctly, however, no voltage flows, as illustrated by you. U (v) = R (ohm) * I (A) or I = U / R or R = U / I Ohm's law is always and everywhere valid in electronics and always applies to the entire circuit. So you need to take LEDs that have less than 2.5V breakdown voltage so that the voltage proportions are correct and voltage can drop / should over the resistor. If you want the 2.5V to drop across the LEDs, you do not need a dropping resistor, which greatly shortens the life of your LEDs! This leaves only 4.2V or 2.1V per LED for the LEDs. If you are running a 40 ohm resistor at 20mA, 0.8V will drop across the resistor. When looking at your chart I noticed that it is wrong - not in the presentation, but in the values. In this respect, one should consider, rather take a MEGA more into the system, rather than consuming perform power and Pinsparberechnungen.įor "power guzzlers", such as stepper motors, you should plan a separate power supply from the outset, because 2 steppers are already a MEGA lame. Mobiflight, on the other hand, can control any number of MEGAs (up to 127, depending on the operating system). A MEGA costs about 10 euros / piece and can control up to 40 LEDs or 50 switches. ![]() Optimization or not, but to maximize the maximum, I do not consider it appropriate to push the MEGA to its limits and save pins. A less goes too and ensures a longer life of the LEDs. can be connected in series to exploit the operating voltage, it may lead to differences in brightness, because the LEDs are subject to both the brightness and the breakdown voltage of a production-related scattering.īy switching the LEDs that you want to connect in series in parallel, you still have the option of individually balancing the brightness by adjusting the pre-resistance.Īs you have correctly stated in your update, and I had already recommended that, LEDs do not have to be operated with the mandatory 20mA. In your case, it's not about being able to pin as few pins as possible and getting the maximum amount of power, but about designing everything for longevity and reliability. Works only with the high brightness LEDs. This one can operate with less than 10mA and still has sufficient brightness. I myself use high brightness LEDs with >8000mcd. So also with the LEDs and the pins of the Arduino. The engine of a car should not always run in the red area, if you would like that he lives longer. But you also describe the values that should not be exceeded as the ultimate maximum. In terms of physical parameters you are quite right. Indeed, if you put 3 leds in series the voltage per led drops below the operating voltage (1,66V conclusion it is impossible car limited to 200mA. The operative voltage of an orange/yellow LED is approximatively 2,1V and the intensity needed is said to be 20mA (can it be less ?)Ĭonsequently, if you want to light 4 LED (example : displaying HDG HDG VS VS or TRK TRK FPA FPA on the fcu) from one pin you only have one option : And the total intensity allowed over all pins is 200mA. I have a question about using LEDs on Arduino Mega.įrom what I understand each digital pin deliver 5V and up to 40mA. ![]()
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