preethi19
Full Member level 5
Hi i have attached an image of a very simple op-amp. I am learning the basics of op-amp.
The 1st image we have the opamp amplifying the difference of the two inputs
and therefore the output voltage, X = 0.99 which is depicted in figure 2. I was taught (just a simple example as such) that now if you take the difference of the two inputs 1V- 0.99V = 0.01. This difference multiplied by gain => 0.01 * 99 which results in an output of 0.99 again. And state will always remain the same and this is known to be the op-amp stable point. I can understand that the op-amp inputs are almost equal which is wat feedback is used for. This example is very simple.
But say i have 3V in the non-inverting terminal and 2V in the inverting terminal and gain is 4. So at first (3-2) *4 = 4V. So now this 4V output is given to the non-inverting terminal.
So next it will be (3-4) * 4 = -4. (-4 now to the non inverting terminal) and so
Next it will be (3-(-4))*4 = 28V. And say out power supply can supply only to 15V So now output will be 15V and will be fed back. And so (3-15)*4 =-48V... This example keeps changing the output. How can i bring it to a stable state like in the first example shown. Like to find the stable point for this example in a intuitive way without any equation. Can someone pls help!!! Thank you!!!
The 1st image we have the opamp amplifying the difference of the two inputs
and therefore the output voltage, X = 0.99 which is depicted in figure 2. I was taught (just a simple example as such) that now if you take the difference of the two inputs 1V- 0.99V = 0.01. This difference multiplied by gain => 0.01 * 99 which results in an output of 0.99 again. And state will always remain the same and this is known to be the op-amp stable point. I can understand that the op-amp inputs are almost equal which is wat feedback is used for. This example is very simple.
But say i have 3V in the non-inverting terminal and 2V in the inverting terminal and gain is 4. So at first (3-2) *4 = 4V. So now this 4V output is given to the non-inverting terminal.
So next it will be (3-4) * 4 = -4. (-4 now to the non inverting terminal) and so
Next it will be (3-(-4))*4 = 28V. And say out power supply can supply only to 15V So now output will be 15V and will be fed back. And so (3-15)*4 =-48V... This example keeps changing the output. How can i bring it to a stable state like in the first example shown. Like to find the stable point for this example in a intuitive way without any equation. Can someone pls help!!! Thank you!!!