76. LED Electrical Characteristics

You are using the Vishay TLDR6400 (5 mm Red LED).

DigiKey part:Vishay TLDR6400 

• At IF = 20 mA and Ta = 25 °C,
• Typical luminous intensity Iv = 70 mcd

Now the ambient temperature rises to 80 °C, while the forward current remains 20 mA.

Approximately what luminous intensity can be expected at 80 °C?

Datasheet Reference: Open the datasheet and refer to Fig. 8 – Relative Luminous Intensity vs Ambient Temperature.