Powering an LED
LEDs are low-voltage devices working within the 1.8Vdc to 2.5Vdc range. LEDs can be included in resistor networks that create a voltage divider network making it safe for an LED to operate.
When powering the LED, the +Ve voltage is applied to the ANODE, and the -Ve is applied to the CATHODE. The voltage requirement for the LED is 1.8v at around 10mA. The calculation for the current limiting resistor below works out the value for an MCU powered at 5 Vdc.
RLed = (Vsup - Vled) / 10 mA
RLed = 3.2 / 0.01 mA
RLed = 320 Ohms
While 320 Ohms is the quotient, you can adjust the value of the resistor as the current flow determines brightness. A higher value reduces current flow and can save power for battery-powered applications.
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Dual-color LEDs can be very useful in applications, and powering them is an extension of the skills taught here.
