Post by Deleted on Jul 6, 2009 20:11:56 GMT -8
Hello. I am new to the forem. As an experimentor in electronics on, and off, for many years. I am an expert builder, and can prove it if neccesary. I have decided to invest in a powersupply. I guess I am taking the DIY(hobby) approach due to my economic status. However I am in need of a lab power supply for my own personal developement in electronics. Weather the power supply on the CHEMELECT site is appropriate for my continued education, I don't know. I salvage alot of electronic parts, useing a desoldering tool that I made, and other test equipement that I have, and investigated other powersupply projects as well. Anyways my question is, can the power supply useing the MC1466L be used to create negative voltage? Now there seems to be some confusion as to what negative voltage is, so maybe this has to clarified first. I have a rather medium adjustable powersupply Harrison Laboratories 6204A that is 0-18V (.600mA) and 18-40v(.300mA). I am rather selfish, and want something better. But to stick to the point, the power supply that I have, and the power supplies that I use to use in a QC laboratory in a job I once had, all have three bannana sockets labeled (+), (-), (gnd). Now I have debated the negative voltage concept while working in the lab to understand it better. I know that (gnd) is just a reference point, and could be either + or -. But according th KVL, the sum(voltage difference) between another point and ground always is equal to that specific point(thus gnd always=0 in the equation). When I connect a DVM between + and gnd, or (-) and gnd, I get no voltage. So I can only assume that the power supply is either broken, or that the gnd is mearly the metal case enclosure box, with no real connection on the circuit board. So there seems to be no way of getting negative voltage out of the powersupply. Hypothetically if I had a negative voltage regulator, I can connect the negative(black), of the DVM to gnd, and Positive(red) to output, I should get a negative sign in front of the value. If I get a positive sign, then its a normal power supply, giving positive voltage. Ideally I would like a powersupply that I can put the DVM Black(probe) to gnd of the power supply and red(probe) to (+) on the power supply, and get a value with a positive sign, and red(probe) to (-) on the power supply with same value with a negative sign. As far as the MC1466L goes, I would make one board exactly like the one on the projects page, and another board that has the following modifications: D20-D23 would be turned around to give neg rectification, and maybe Q17,Q18,Q15 would be PNP of simular parameters(including Beta), instead of NPN. I'm not assumeing that these would be the only modifications, or that this would be the only thing that would have to be done. Not at all. I am just throwing some of them in the air. Then the grounds of the two power supplies boards can be connected to give the (+),(-),(gnd) I described above to give adjustible negative, positive voltages with adjustable current. Not many power supplies on the market that can do this. And I know that I might be climbing out on a limb here by suggesting this. If I am then I will just try I live with a regular normal power supply like every other electronics tinkerer out there. I am an inventor, and I like to keep my options open. If you can maybe keep an open mind about this and give some suggestions, without getting upset, please let me know. I promise I will use caution. Thanks alot. 
