Create a free Team What is Teams? Learn more. Asked 1 year, 3 months ago. Active 1 year, 3 months ago. Viewed times. JRE Mahmoud Salah Mahmoud Salah 1 1 silver badge 9 9 bronze badges. If it's stuck at one of the output rails you have something else wrong. You can add one in using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. Note that when you use the CircuitLab button on the editor toolbar and "Save and Insert" on the editor an editable schematic is saved in your post.
That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid. A is not a single supply opamp.
You CAN use it as one, but not like this! Read that datassheet again, noting how close the output can swing to each supply rail.. Maybe you're not using them correctly? Not surprising as it's a 52 year old design.
Show 1 more comment. Active Oldest Votes. The original circuit. Edit after question updated. Figure 2. The modified circuit. Transistor Transistor k 11 11 gold badges silver badges bronze badges. You've effectively made one.
Do you even understand the importance of split supplies for analog circuits? A 's output can't swing much less than 3 volts above the negative supply rail.
One voltage is called the reference voltage and the other is called the input voltage. It is a circuit which compares a signal voltage applied at one input of an op-amp with a known reference voltage at the other input. LM is a quad op amp integrated circuit with high stability, bandwidth which was designed to operate from a single power supply over a wide range of voltages.
They have some dissimilar advantages over standard operational amplifier types in single supply applications. It is a pin dual in-line package, contains four internally compensated and two stage operational amplifiers, shown in figure.
Potential dividers of LM are connected to the inverting and non inverting inputs of the op-amp to give some voltage at these terminals. The output of this comparator will be logic high if the non-inverting terminal input is greater than the inverting terminal input of the comparator.
When the inverting input is more than the non-inverting then logic low 0 will be the output. It has four inbuilt comparators; it compares two input voltage levels and gives digital output to show the bigger one.
These comparators additionally have a unique characteristic in that the input common-mode voltage range includes ground, in spite of the fact that they are operated from a single power supply voltage. Potential dividers of LM are connected to the inverting and non-inverting inputs of the op-amp to give some voltage at these terminals. The LM op-amps are used in transducer amplifiers, dc gain blocks and all the conventional op-amp circuits which now can be more easily implemented in single power supply systems.
The inverting input of the comparator LM i. When the resistance between the positive supply and the non inverting input is high then resulting is the non-inverting input less than the inverting input making comparator output as logic low at pin1. And when the resistance falls making available a voltage to the non-inverting input higher than inverting input, so that the output of comparator is logic high.
It is excellent Op Amp that requires very low input current requirements. Its output will be in the zero state in the off mode. The input current can be as low as 10pA. The presence of PMOS transistors at the inputs results in common mode input voltage capacity down to 0.
So it is ideal in single supply applications. The output has CMOS transistor pair that swings the output voltage within 10mV of either supply voltage terminal. IC CA works off 5 to 16 volts and can be phase compensated with a single external capacitor. It also has terminals to adjust the offset voltage and strobing. It is the 4. It has both PMOS transistors and high voltage bipolar transistors inside.
The input current requirement is very low around 10pA. It exhibits very fast response and high speed of performance. The output has protection against damage from load terminal shorting. The IC is internally phase compensated for stable operation. It also has terminals for additional frequency roll off and offset nulling. It operates in wide common mode and consumes very little current. Offset voltages occur because the manufacturing processes are not perfect and there are small differences which combine to look like a single input voltage rror.
They may be distributed through the IC but can be represented by and corrected by an offset voltage. It'd be more insightful, I think, to ask why there would be no offset voltage. Once you pose the question that way, you can realize that perhaps physical objects can't ever be perfect, so it'd be rather unexpected to assume that one particular physical object - an operating amplifier - would be somehow exempt from the rules that affect everything else in Nature.
As to why exactly an op-amp has input offset: the input circuitry isn't perfectly symmetric, in various ways. Some general refs say you bridge across the nulling inputs of op amps with a pot with it's wiper at 0V and others at V-. Frost's answer at electronics. Add a comment. Active Oldest Votes. This error is also characterized by the datasheet: It can be safely ignored in AC applications, where this offset will be ignored by the AC coupling. Phil Frost Phil Frost An ideal op-amp has no offset because its gain is infinite, there are no leakage currents, and there's no undesired impedance anywhere.
Any real op-amp will necessarily have these things, the being no exception. An op-amp with non-zero offset and infinite gain, in a negative feedback configuration, will simply drive it's output to the point that the two inputs differ by the offset voltage, which is likely to cause an error at the output relative to the desired output. If an op amp has an input offset of X and output offset Y, the output will be voltage Y away from the point where the inputs would be voltage X away from each other.
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