Drawing schematic diagrams once took a great deal of skill; skill in line with what a draftsperson would’ve been expected to have when drafting was done by hand. Today, there are numerous electronic solutions to the problem of drawing schematics for electronics.
Most of today’s schematic diagrams are drawn on software. This ensures consistency and ensures that the schematic diagrams are always readable to anybody who needs to use them, as the symbols never vary between one and the next and all of the appropriate information is included on the diagram.
Some electrical engineers, however, and some hobbyists, are quick enough to draw schematic diagrams of whatever they’re creating on-the-fly. This skill is an excellent one to develop if you plan to use electronic components to build appliances from scratch. All you need to do this is a good pencil and some graph paper and a cheat sheet that gives you all of the various schematic symbols that you will need. You can print out the following information and you will have at your fingertips the most commonly used schematic symbols in electronics.
Be aware that some of the schematics typically show up with additional information written alongside them. For instance, a power supply will generally indicate how much power it puts out rather than just saying it puts out power in general. There are also quite a few subtleties involved with the symbols, as well. For example, the symbol for a battery is actually drawn in a way that indicates to the reader how many power cells are included in that battery, which allows the reader to determine how much power each of the cells is putting into the circuit. This type of subtlety is what makes schematic diagrams so eminently useful to electrical engineers and to hobbyists.