Led anode vs cathode how to#

LEDs need a certain amount of current to light up correctly. If we put 2 LED in series, connecting the anode of the second to the cathode of the first, we’re going to see they both cause a voltage drop of 1.85V (more or less like before, 1.87V), and the resistance causes a minor voltage drop compared to before, just 5.29V:ĭifferent LEDs will have different voltage drops, depending also on the color, called nominal forward voltage, and you can get that via direct measurement. The 5mm LEDs I got in the Elegoo box of electronic components points me to this data sheet which states the continuous forward current is 50mA, with a peak of 100mA. How much current is too much? This is determined by the LED manufacturer, on the specification sheet. If we had a 300Ω resistor, the voltage drop on the LED would be 2.10V and the current through it will be 22.9mA.

The resistance will limit the current and will have a 7,12V voltage drop: The LED has a voltage drop of 1.87V (the exact value will depend on the LED model). With a resistance, all works as expected.ĭepending on the value of the resistance, the voltage drop on the LED will be different. WARNING: with too much tension/current the LED can also explode We used a resistance to limit the current flowing through the LED, otherwise it would likely burn because a LED has a tiny amount of resistance, and due to this the current flowing through the circuit would be too much.

Led anode vs cathode how to#

You already saw how to light a LED with the help of a battery and a resistance. I’m not going to explain how, just know that it’s a reaction of the material they are composed of when current flows through it. When a certain amount of tension and current applied through the wires, the LED will light up. Here’s how its wires compare to a diode connection:Ī LED is like a tiny lightbulb, with various color options: It works exactly like a diode, except it emits light. Note that the cathode has a shorter lead, but if the leads are cut it might be hard to figure out which connection is the cathode - in the case of a 5mm LED, the cathode has a little cut through the shape, it’s not a perfect circle like in the side of the anode. It’s important to not invert this order, or the LED will not work. We connect the anode to the + positive lead and the cathode to the. Typically the anode is longer than the cathode: Connect the short leg of the LED (the negative leg, called the cathode) to the GND. Connect the long leg of the LED (the positive leg, called the anode) to the other end of the resistor. This LED has 2 leads, one is the anode and other is the cathode. Connect one end of the resistor to the digital pin correspondent to the LEDBUILTIN constant. The ones we’ll talk about here is the ones commonly used for prototyping, the 5mm LEDs. Some are high-power, like the ones used for automotive lights. There are various kinds of LEDs, for various applications and uses. A Light Emitting Diode, also called LED, is one of the first electronic components you use in your experiments, because it’s simple to use and due to its nature it’s perfect to explore all the concepts we’re learning.