Microsoft Office Visio is good

For schematics with discrete components, opamps, comparators and alike: one of the Spice variants from all major semiconductor manufacturers (e.g. LTSpice from Linear).

For complex designs with ICs: e.g. KiCad.

You are free to use wikipedia to find more of such solutions :)

To draw any kind of diagram and circuits, you can use XFIG in latex platform.

Thank you.

xcircuit is a good software in my opinion.

Microsoft Office Visio

xcircuit doesn't give high quality circuit diagram. output of xcircuit is in JPG format whereas xfig gives in EPS format which is mostly used format by research community.

Thank you

In my personal experience, the best software to get high-resolution images suitable to be included in scientific paper is Microsoft Visio.

Microsoft Office Visio is good

I use Microsoft Word. It takes some time to build the symbols but for the typical circuit diagram used in an article, it is not to bad. Easiest way to create the symbol is to find a picture of the symbol you want then draw over it at 500%. After you draw it, group it, move it off the picture then delete the picture. That way you can shrink to size and rotate your symbol at will. All the other functionality of a CAD is cantained with in Word. To make life easier be sure to save the file as a .doc (older format) which makes manipulation easier in the future. The beauty is that all is done within Word so there are no nasty compatibility issues and the diagram can be edited at any time in the event changes are necessary. Finally, create a document called Word symbols. Save all created symbols so they can be reused.

Thank you all for your valuable answers.

Thank you dear Mike for the detailed replay. It is interesting.

Dear Rohith.

For drawing high quality circuit schematics, I would suggest you to take a chance on the latex+circuitikz suite. First steps with these tools might be hard to follow, but once you master it, the results are quite impressive.

Here you have some examples: http://texample.net/tikz/examples/circuitikz/. If you are latex user, you will find it rather simple.

Thank you dear Fernando.

I have attended few latex workshop and the software is impressive. I will surely try your suggestion.

Thanks,

Rohith

LTspice schematic is good. Tools-->copy bitmap to clipboard. Then paste it in word.

Also Microsoft Office Visio is good by saving the final schematic as .emz.

Moreover, Visio helps to improve the quality of plot from LTspice or PSpice as in the following links:

Research Export LTspice Figure to Visio

and

Research Enhance PSpice figure using Visio

Also Sapwin4 is a free software for basic circuit element

Copy to clipboard

to download it:

http://cirlab.dinfo.unifi.it/Sapwin4/

Thank you very much Dear Cander Smat for your valuable response. I will surely try them.

If you don't mind something for free, try http://www.designsim.com.au/GEX.html

(See attached image)

Thank you very much dear Dr. Mark Sitkowski .