Comparison of 5mm LED Colours and Brightness: Guide for South African Makers

Overview: 5mm LED Colour & Brightness

5mm LEDs (Light Emitting Diodes) are among the most widely used indicators in hobby, education, and industrial electronics. Available in many colours-like red, green, blue, yellow, and white-each hue offers distinct electrical properties and brightness levels. For South African students and engineers, understanding these differences helps in designing visually effective and reliable circuits.

A 5mm LED refers to the diameter of the lens housing, making it a standard choice for breadboards, panel indicators, and DIY projects. Different colours are made by doping semiconductors with varying materials, affecting:

• Forward voltage (V_f) required to illuminate
• Luminous intensity, usually measured in millicandelas (mcd)
• Viewing angle and perceptual brightness

Key Standards & Specifications

Each LED colour has characteristic forward voltages and brightness ranges. The table below highlights typical values for standard 5mm through-hole LEDs as seen in South African electronics labs and classrooms.

These values are based on widely sold 5mm LEDs at standard operating currents (typically 10-20 mA). Actual brightness seen by the eye will also depend on the viewing angle and ambient lighting conditions.

How LED Brightness is Measured

Brightness is typically specified in millicandelas (mcd). Higher mcd means more visible light when viewed head-on. However, LEDs with very narrow beams can appear brighter in one direction but less so from the side. Consider application: for a broad indicator, wider angle may be better than pure mcd values alone.

Selection Criteria: Choosing the Right 5mm LED

Selecting a 5mm LED isn't just about colour preference-it's also about matching voltage, brightness, and viewing angle to your circuit needs. For South African projects, local stock from Communica covers many variants, including high-efficiency and diffused types for clear indicators without dazzling brightness.

• For panel indicators: Choose classic red or green for easy recognition.
• Outdoor/bright environments: Opt for high-brightness white, blue, or clear-lens LEDs (over 8,000 mcd).
• Classroom and breadboard use: Diffused types are easier on the eyes and show colour well from all angles.

Calculating the Series Resistor for a 5mm LED

Running a 5mm LED safely requires a current-limiting resistor. Use Ohm's Law to determine the value:

• R = (V_supply - V_f) / I_LED

Where R = resistor value (Ohm), V_supply = supply voltage, V_f = forward voltage from the LED table, I_LED = desired current (typically 15-20 mA, or 0.015-0.020 A).

Always round up to the next-highest standard value to protect your LED. For South African 12V and 5V circuits, standard values (e.g., 330Ohm, 470Ohm, 1kOhm) are regularly stocked at Communica in packs or singles.

Troubleshooting: Common LED Issues

• LED won't light: Check polarity-long leg is anode (+); test resistor value, and ensure power is present.
• Too dim/bright: Confirm resistor value matches your circuit voltage and LED type. Overdriving will shorten LED life.
• Flickering/blinking: This may result from loose breadboard connections or intermittent power supply issues (try re-seating wires or testing your PSU).

South African LED Brands & Stock Tips

Communica stocks both generic and preferred brands of 5mm LEDs, including options from companies like Adafruit (for premium diffused packs), as well as a wide range of resistors, panel mounts, and accessories-all available locally with VAT invoicing for education and business use. Popular choices include assorted colour packs, high-brightness types, and compatible mounting bezels for professional projects.

Quick Reference: Pros & Cons of Common Colours

Sources

• Communica - LEDs Category
• Adafruit - 5mm LED Series Datasheets
• Electronics Tutorials - Light Emitting Diodes
• All About Circuits - LED Resistor Calculator Tool
• OSRAM - LED Colour Specs & Product Finder