The Planck’s Constant lab in Advanced Physics – Beyond Mechanics requires 4-5 LEDs of various colors. In general most LEDs would work for this lab. The ones easiest to use are “through hole” (i.e. designed for use in a breadboard or to be soldered by hand), 5 mm in diameter, and have a 360 degree visibility. (But the diameter and visibility are less important parameters since students are using sensors to detect when they turn on.)

Superbrightleds.com has many LEDs that will work for this lab. Here are a few (Color – part number):
Red – RL5-R10-360
Orange– RL3-O3214
Yellow – RL5-Y3545
Green – RL5-G20-360
Blue – RL5-B08-360

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