Digital Logic Functions | Ladder Logic | Electronics Textbook The common association between contacts is denoted by the label of the contact. There is no limit to how many contacts per switch can be represented in a ladder diagram, as each new contact on any switch or relay (either normally-open or normally-closed) used in the diagram is Author: Tony R. Kuphaldt “Ladder” Diagrams | Ladder Logic | Electronics Textbook NomenclatureOperationExampleEffectsSafetyThe L1 and L2 designations refer to the two poles of a 120 VAC supply unless otherwise noted. L1 is the hot conductor, and L2 is the grounded (neutral) conductor. These designations have nothing to do with inductors, just to make things confusing. The actual transformer or generator supplying power to this circuit is omitted for simplicity. In reality, the circuit looks something like this:See more on allaboutcircuitsAuthor: Tony R. Kuphaldt PLC Ladder Diagrams for Electrical Engineers (Beginners) Introduction to PLC ladder diagrams. As an introduction to ladder diagrams, consider the simple wiring diagram for an electrical circuit in Figure 1a diagram Ladder Diagram | Schematic Diagram | Wiring Diagram A wiring diagram is an electrical print that shows connections of all components in a piece of equipment.A schematic diagram is a type of drawing that illustrates the electrical connections and functions of specific circuit arrangements with graphic symbols.A ladder diagram is a diagram that explains the logic of the electrical circuit or system using standard NEMA or IEC symbols. Electrical Ladder Drawing Basics | EC&M Electrical ladder drawings are still one of the common and reliable tools used to troubleshoot equipment when it fails. As with any good troubleshooting tool, one must be familiar with its basic features to make the most of the diagram in the field.