How to read and understand an Electrical Schematic A schematic can contain few or many symbols and connections and is normally read from left to right, top to bottom. Symbols. Symbols are quite literally the building blocks to any electrical schematic. Symbols are a pictorial representation of the electrical component and usually display their respective connection points. Electrical Symbols Category – Free CAD Blocks in DWG file A collection of 2D electrical symbols. A free AutoCAD block DWG file download. Includes: Three phase wiring: 3 phases, neutral, earth Single phase wiring: 1 phase, neutral, earth Moulded branch connection Design current used for voltage drop calculations Current transformer Distribution board tag number Electric Drive : Types, Block Diagram, Classification and Electric Drive Block Diagram Power Source. The power source in the above block diagram offers the necessary energy for the system. And both the converter and the motor interfaces by the power source to provide changeable voltage, frequency and current to the motor. Power Modulator. This modulator can be used to control the o/p power of the supply.