Inkscape can be used to create very detailed technical images, as well as importing images and text from PDF files.
If you click on the image of the heart, you'll see a sample technical document describing electrocardiograms. The
circuit diagram was obtained from the Analog Devices AD620 instrumentation amplifier data sheet which is available from
the Analog Devices web site
http://www.analog.com/static/imported-files/data_sheets/AD620.pdf. The schematic diagrams of the heart and ECG trace
are both available from the Wikimedia web site
which boasts a large number of creative commons scientific images.
It is also possible to add math equations in Inkscape using LaTeX notation. To do this, you will need the textext program available at http://www.elisanet.fi/ptvirtan/software/textext/index.html as well as the pstoedit program. I have not personally tried to use this as I usually incorporate Inkscape figures into my LaTeX documents, rather than incorporating LaTeX equations into my Inkscape figures.
Although the electrocardiogram example uses a schematic from a pre-existing document, it is also possible to draw
circuits in Inkscape using the snap feature which will align objects to a grid. This is easy to do if you already have
a pre-defined set of circuit elements which can be joined together to build
You can also use the program to layout circuits on printed circuit boards. The PC board shown on the right is based on Art's minimum theremin and uses a model 777 prototyping board available from Futurlec.