As I was re reading this email I noticed that he made some edits since he first posted, specifically the last thing he mentions about it working. After going back I saw that he added an edit to one of his posts. Him: The operating conditions for all tabular data and for every graph stipulates split supply operation. You won't find a any reference to single supply operation on any spec sheet for the 741 from any manufacturer. EDIT: I checked the most recent (2015) TI specification and it says "The LM741 can operate with a single or dual power supply voltage." All tabular data and graphs still stipulate split supply operation and the common mode range still doesn't include ground when a single supply is employed. A single supply op amp is specifically designed to have a common-mode range which extends all the way to the ground. Its output stage is usually designed to swing close to ground. The 741 does not incorporate either of these design attributes. On Dec 2, 2017 4:53 AM, "James Burkart" wrote: > Over on reddit (r/AskElectronics) a guy was having troubles getting a > circuit to work. His problem was that he was using an LM741 with a single > 5V supply and expecting it to operate near the rails. Everyone was helpfu= l > and explains the 741's limitations and suggested another opamp. But I too= k > issue with what another redditer said, that the LM741 was not designed fo= r > single supply operation. The following was the discussion that followed. = Am > I just completely wrong? > > > > Me: I wouldn't say that it's "not designed" for single supply operation. > Just gotta know that it's not a rail to rail opamp and so in single suppl= y > operation it's output can never reach 0V, which happens to be it's negati= ve > rail potential. > > Him: It's actually not designed for operation from a single power supply. > Not my opinion it's straight from the Fairchild specification sheet. I= n > fact it kinda, sorta, operates with a single power supply but will not > perform as specified. > > Me: Where in the Fairchild spec sheet does it say that? > > Him: The operating conditions for all tabular data and for every graph > stipulates split supply operation. > > You won't find a any reference to single supply operation on any spec > sheet for the 741 from any manufacturer. > > A single supply op amp is specifically designed to have a common-mode > range which extends all the way to the ground. Its output stage is usual= ly > designed to swing close to ground. The 741 does not incorporate either o= f > these design attributes. > > Me: There is no ground pin on the 741 so the amp isn't even aware of wher= e > ground is. Single supply or split supply, the thing works exactly how it'= s > supposed to. Obviously one needs to design the circuit to operate within > the capabilities of the components used, so if the designer needs the amp= 's > output to swing negative then he's obviously going to use a split supply. > But if he doesn't need the output of the amp to drop below 2V, or his > circuit requirements allows him to float his ground, then unless another > part of the circuit requires a split supply, there is no need to use a > split supply, and the 741 will work exactly to spec, assuming all else in > the circuit design is correct. > > Him: If it's operating on a single power supply the negative pin is > connected to ground. Common mode operation does not include ground so it > will not meet specification. That said if you can keep the input within > the restricted common mode range, about 2V above ground, it will work. > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .