# Tag Info

6

There are a range of methods which can be used to provide offset voltage compensation. The best method to use varies with the application circuit but all either apply a variable current to a circuit node or vary the voltage of a node which a circuit element connects to. The methods described below can easily be applied to your circuit by Adding a ...

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Capacitive coupling has been suggested, but this has two big disadvantages: Your signal is no longer a square wave It will only center your signal around 0V if the duty cycle is 50%; you'll see the signal go up and down if you play with the duty cycle A good function generator will have a potmeter to set an offset to the signal. One way to do this ...

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What you need to do is simply remove the DC offset all together, not supply a negative one. This is known as AC coupling. If you run the output of your square wave generator through series capacitor, it should do what you need. This will however be at the expense of making the square wave less square. An example circuit is shown below for you: And the ...

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Several comments: Add component designators to your schematic. It is difficult to talk about the circuit otherwise. You appear to be a little confused about resistor dividers. You have two resistor on the input, but only one is doing anything. The resistor to ground is just a load on the input but otherwise has no bearing on your circuit. It sortof ...

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The offset voltage is increasing as you have increased the gain and you have the non inverting input set above "mid point". With the top circuit there is actually attenuation, so the opamp doesn't have to drive it's output very hard to keep the inverting input at 2.5V. When you increase Rf to 10Meg, the output has to drive it's output to the necessary ...

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Note that the 20mv error is a measure of how close the output can go to 0v (using your supplies) against a 100 kilohm load pulling the output to "mid-supply" i.e. 2.5V. Without that pull-up, as in your application, the output will go considerably closer to 0V. However if you need to inject offset; the place to do it is "ref" i.e. pin 6 - whatever voltage ...

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This link has it sorted out. In general, you have to inject correcting voltage into one of inputs. This PDF has it for inverting and noninverting configuration.

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You can couple it with a capacitor to the load, but depending upon the load impedance and the capacitance it will roll off the edges of the squate wave. If that is a problem you can add a buffer amp stage to match the impedance. The capacitor will give you the expected AC couple your looking for. This is an easy circuit to simulate in a spice program such ...

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