# Plotting values into the graph

I recently found this op amp exercise and solved it using superposition .The result was UA

I first need to draw U1 and U2 and then based on UA draw the output result.Stuck doing this and now way to figure it out if I'm doing this right so I came here for some needed help

This is my attempt to just plot U1 and U2 without then trying to plot the output UA.

Asking for some advice if my approach of graphing this is right. U1 seems to be right I'm just not sure about U2

• I'm voting to close this question as off-topic because it is a generic question about graphing software, not specific to electronic design. Jan 14, 2020 at 20:24
• @Elliot Alderso, I have edited the question. Would really appreciate some advice Jan 14, 2020 at 20:51
• I think you have U1 and U2 exchanged in your graph. Also you can see that U1 should hit 2V at 20us, and thus 1V at 10us Jan 14, 2020 at 21:11
• @jonathanjo, yes U1 and U2 are exchanged. Can you please give an answer on how would you go on graphing this. I want o understand the concept . Would appreciate it a lot Jan 15, 2020 at 9:23
• @be1995 see answer given below Jan 15, 2020 at 12:57

I can tell you nothing about what these functions mean with regard to op-amps, but the following should help you get the graphs you're after.

U1 is a linear function on t, Û1 is essentially a scalar constant to adjust the amplitude, and T1 is a scalar to adjust the slope. The function is defined over a T1 wide period centred on t=0, ie, from -T1/2 to +T1/2.

U2 is a sinusoidal function on t, expressed as a cosine so it is also centred on t=0, so expressed as cosine. Û2 scales the amplitude to 2V. f2 is the frequency: 2π is the constant to convert cycles to radians.

UA is simply a linear combination of those two functions.

The two easiest ways to graph this are use either a graphing program/website or a spreadsheet.

## Graphing Website

You might find the graphing site https://www.geobra.org/graphing helpful. I use it for quick graphs of this kind. There are plenty of graphing packages and sites available.

First I folded up the constants and multiplied everything by 1,000,000 just for convenience, giving T1=20 and f2 as 0.1. Then you create the three functions by typing them in to the box on the left (by the three coloured dots). You might have to read the manual to see how to type in the functions, but it's easier than it looks. The program then just draws the graphs for you. If you click on the graph lines or coloured dots you can see various values on the graph (eg points of inflection).