Let me start off by clarifying that I'm not a design engineer, so I'm
just seeking some help, and apologize in advance if I'm unclear.
What I want to build is a regulated 0-30v 0-3a DC supply, adjustable
current and voltage. I want to build it for personal gratification, I
know I could just purchase a HY3003, but what's the fun in that?
Looking at the schematic on Bowden's Hobby Circuits,
http://ourworld.compuserve.com/homepages/Bill_Bowden/page4.htm#ps6.gif
it looks like this supply has no line regulation. Am I wrong? I
think it has load regulation, as the input for the voltage portion is
fed directly off the output, but there is no input reference. Please
correct me where I am wrong, I'm sure I am.
Looking at the LM317 datasheet,
http://www.national.com/ds/LM/LM117.pdf
page 17, they show a regulated adjustable voltage and current supply.
But this will not go to 0 V, only to 1.2V. On page 16, they show the
negative supply to allow the output to adjust down to 0v, but how do
you incorporate this into the adjustable current schematic shown?
Just bring the voltage adjust pot down to -1.2V? How will this affect
the rest of the circuit, specifically the current limiter? Am I
making this too complicated?
Thanks for your help, all thoghts appreciated.
Steve
