Electronics isn't just about connecting plugs to power sockets nor as simple as looking at models of simple circuits with a dry cell. There are lots of signs and symbols that you should memorize in order to create well functioning appliances, gadgets, etc.

If you're studying the field, this application would be of major help to you. It is basically an electronics toolkit where you can learn more about resistor color codes, the ASCII, air core conductors, and more. It also comes with different calculators; voltage divider, Ohm's law, parallel capacitors, series capacitors, unit converters, and the likes.

It has everything you need and you can study them completely free.