I have used the LM-324 op amp for several things here over the years 
exactly because of its ability to operate from a single power supply, namely +9 
volts DC and GND.
         

        ---- Original Message ----
        From: "gregebert" <gregeb...@hotmail.com>
        Sent: 4/5/2021 7:29:22 PM
        To: "neonixie-l" <neonixie-l@googlegroups.com>
        Subject: Re: [neonixie-l] LM-324 op amp
        
        If the loop-gain is sufficiently low, any non-linearities at the output 
will get self-corrected (because of the negative feedback) at low-frequency. If 
the signal frequency is high-enough, or if there is low-bandwidth in the 
feedback network, then the output will definitely behave differently than you 
would expect due to the frequency response of the OP-amp (or your feedback 
network, such as an RC filter that isn't properly designed).

         

        This is where SPICE simulations are imperative. I wont use an OP-amp 
unless the manufacturer provides a SPICE model.

         

         

        
                On Monday, April 5, 2021 at 2:53:16 PM UTC-7 Terry Bowman wrote:
        
                
                        
                        
                                
                                        
                                                On Apr 1, 2021, at 8:52 AM, 
chuckrr <chu...@all2easy.net> wrote:
                                        
                                        
                                                
                                                        Doing do on an LM-324 
runs the output at around 7.45 volts
                                                        when the chip is 
operating from a single 9 volt supply.
                                        
                                
                        
                        
                                 
                
                
                        This reminds me of an aspect of the LM324 worth 
including in this thread. It's the kind of real-world issue that doesn't come 
up until the second or third chapter of an operational amplifiers textbook. I 
doubt that it's a concern for the original poster but I'm a bit hazy on details 
myself so I'm hoping that someone else can remind me.
                        
                                 
                        
                                The LM324 is capable of working reliably on 
both bipolar and single power supplies. This versatility combined with its low 
price makes it a good all-around choice for a wide variety of less critical 
applications.
                        
                                 
                        
                                A friend of mine, someone much cleverer than 
I'll ever be, ran into what he assumed to be limitation imposed by its single 
supply capability. He was designing a circuit with a bipolar PS and simply 
couldn't get the 324 to behave. IIRC, he told me that there's glitch that 
occurs when the output crosses zero volts while slewing from negative to 
positive.
                        
                                 
                        
                                He ended up using something else, problem 
solved. Has anyone else heard of this?
                        
                                
                                         
                                
                                         
                                
                                        
                                                
                                                        
                                                                
                                                                        Terry 
Bowman, KA4HJH
                                                                        "The 
Mac Doctor"
                                                                         
                                                                
                                                                        
https://www.astarcloseup.com/
                                                                
                                                                         
                                                                
                                                                        “...the 
book said something astonishing, a very big thought. The stars, it said, were 
suns but very far away. The Sun was a star but close up.”—Carl Sagan, "The 
Backbone Of Night", Cosmos, 1980
                                                                         
                                                        
                                                
                                        
                                
                        
                
        


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