22.3. Vision http://www.ck12.org
- LED traffic light: User:Bidgee/Wikimedia Commons. http://commons.wikimedia.org/wiki/File:LED_traff
ic_light.jpg. CC BY 3.0.
marvins-underground-k-12
(Marvins-Underground-K-12)
#1
22.3. Vision http://www.ck12.org