I've come across an interesting irregularity while designing a arduino LED controller. I wanted to measure the current draw of my LED strip to determine power requirements. I was curious as to which color was drawing the most power, and I noticed that when measuring the colors individually the current did not add up to the current measured when combined.
Here is the data I recorded, all measurements are in Amps.
12V Supply 1A 4A G 0.88 0.97 R 0.53 0.56 B 0.68 0.76 GR 1.2 1.35 GB 1.24 1.44 RB 1.03 1.16 RGB 1.48 1.75 G+R+B 2.09 2.29
The single characters R G B are the individual colors measured, the double characters are the combination of two colors measured together, and the RGB is the measurement of all three colors at the same time.
There is a substantial difference between the individual measurement for R+G+B and RGB. Is this some characteristic of RGB LED?
Also, I tested the current with two power supplies, one is rated for 1A, but is showing a draw of 1.48A. Is is more likely that the supply is underrated, or is it more likely that it is broken?