I am trying to build a circuit that sets a few small DC outputs. Some of these will need to be tuned from negative to positive, pretty much over the range from -1 V to 1 V. I figured a variable voltage regulator and a good pot would be able to do the trick, as we have both lying around, and a +/- 5V supply I have on order.
On the data sheet of the National LM317 series they have a "0-30V" circuit with the pot connected between a 1.2V Zener reference and a resistor which goes to a -10V supply. Could I just hook up a normal pot without the zener and resistor? In my circuit I will be hooking up another part between ground and 5V, so I'm not sure if I can treat the negative rail as a virtual ground. I can't find any zero-crossing circuits in a couple of books I've looked at, or in data sheets, so I am suspicious I am overlooking something that will blow my circuit.
It seems to me that a zero-crossing voltage source is useful in general. Why aren't there more of these in the market, or diagrams on the net or in books?
Thanks for your help.