DIY Microcontroller Projects for Hobbyists by Miguel Angel Garcia-Ruiz Pedro Cesar Santana Mancilla

Author:Miguel Angel Garcia-Ruiz, Pedro Cesar Santana Mancilla
Language: eng
Format: epub
Publisher: Packt Publishing Limited
Published: 2021-06-29T00:00:00+00:00

Introducing super-bright LEDs and calculating their necessary resistors

A super-bright LED is a light-emitting diode (LED) that glows with high intensity, higher than regular LEDs. LED brightness (light intensity) is calculated in millicandelas (mcd). Bear in mind that 1,000 mcd equals 1 candela. Candelas typically measure how much light is generated at the light source, in this case, an LED, but candelas can be used to measure other light sources, such as light bulbs. The super-bright LED that we use in this chapter is rated as 6,000 mcd, emitting a nice and powerful orange glow, which is quite bright when connected to a proper current-limiting resistor. In comparison, typical LEDs are rated at a range of about 50 to 200 mcd.

Super-bright LEDs have a special design to increase light diffusion by using a transparent glass coating and reflective material. However, some super-bright LEDs have a reduced viewing angle (the observation angle with the LED light looks more intense) of about 35 degrees, such as the one we are using in this chapter, whereas the viewing angle of other regular and super-bright LEDs is 120%. This viewing angle depends on their cost, efficiency, and applications.

As with regular LEDs, super-bright LEDs require a certain voltage to power them, typically between 2 and 3 volts. That's why we need to connect a current-limiting resistor to an LED to reduce its voltage. We can use the formula R=(Vs-Vf)/If for calculating a current-limiting resistor for an LED in the following cases:

Vs = supplied voltage. The Blue Pill and Curiosity Nano output ports provide 3.3 V.

Vf = forward voltage, which is the voltage that drops through a resistor.

If is the forward amperage (amps).

R is the resistor value that we want to calculate.

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