Does anybody know a good commercial book or free web tutorial
for learning to read and understand schematics respectively electronic circuits?

Thanks for help.

 

To understand a schematic you have to first understand the underlying circuitry, so I suppose some general electronics book should help you, for example the Allaboutcircuits ebook. After you read it through, you should have a much better understanding of electronic circuits. After that it depends on what kind of schematics you wish to understand, i.e. high voltage power, digital, radio-frequency circuits etc.

 

Pay special attention to Volume 6, the experiments section. It will have schematics next to drawings of the actual wiring. You can compare the two, and see what is what.

 

Thanks. I am already familiar with basic circuit components. But I have problems to catch the essence of complicated layouts e.g. follow the currents. It is getting more complicated if there are also filters, amplifiers, pwm etc.

 

Thanks. I am already familiar with basic circuit components. But I have problems to catch the essence of complicated layouts e.g. follow the currents. It is getting more complicated if there are also filters, amplifiers, pwm etc.

play around with this:
http://www.falstad.com/circuit/

animates things like current and voltage.
there's lots of basic circuits to start with