Anyone do have positive and negative power supply circuit for 0-30v with corse, fine and also current adjustment? Please help me on this. Thanks in advance.
However, you can make a much simpler one if you are willing to live with 1.25-13v or so. Try searching for LM317 (positive) and LM337 (negative) linear regulator and look at the datasheet for example circuits, such as here: **broken link removed**
It shows you things like how to make the circuit work from 0-30V, add current limits and so on... but linear regulators are going to waste a lot of power with such a wide voltage range. A good power supply design that work over that wide a range is complicated.... I strongly recommend you to see if you can live with something a bit more modest to start off.