I'm starting to build a test board using a small perf board. I placing several LED's on the board and basically, at this point, that is what the board will do. There are 22 LED's and I have broken them up to use 4 LED's per resistor. I have looked on-line and find people place the resistor at the start of the 4 and have also seen it placed at the end of the LED line.
Which is correct?