I came across this a while ago...
... and need to implement something similar but I can't figure out how to calculate the output voltages/current etc. I know Ohms law but am not so hot at applying it. So yeah, this is a pretty basic electronics question. :)
According to http://www.javiervalcarce.eu/wiki/TV_Video_Signal_Generator_with_Arduino where I stole the image from, the outputs are as follows:
P7 = 0, P6 = 0, Vo = 0v P7 = 0, P6 = 1, Vo = 0.3v P7 = 1, P6 = 0, Vo = 0.6v P7 = 1, P6 = 1, Vo = 1v
But could someone spare a few minutes to show me how those output voltages were calculated? You'd really be helping me out.