Electrical Diagram Types
Choose a drawing by the question it answers: appearance, connections, function, control logic, or physical location.
Choose the drawing for the job
Choose the drawing for the job
One electrical system can need several drawings. Start with the question: What does the part look like? Where does this wire go? How does the circuit work? Where does the equipment fit?
| Type | Shows | Usually leaves out | Who uses it, and when |
|---|---|---|---|
| Pictorial | Recognizable appearances of parts. | Exact electrical behavior and hidden connections may be omitted. | A beginner or assembler identifying parts before tracing connections. |
| Block | Functions and the direction of signal or power flow. | Individual terminals, component values, and return wires. | A designer explaining a system before working out its circuits. |
| Wiring | Connections between terminals; wire identifiers and routing where specified. | The reason the circuit behaves as it does; scale may be omitted. | An assembler or service technician connecting or tracing wires. |
| Schematic | Electrical function and connections using component symbols. | Actual component positions, wire lengths, and enclosure geometry. | A circuit designer or technician analyzing how a circuit works. |
| IC / PCB layout | Physical geometry: a PCB has footprints, pads and copper traces; an IC layout describes structures and interconnect on a chip. | A convenient explanation of circuit operation. | A board or chip designer checking placement and routing before manufacture. |
| Ladder | Relay or PLC control logic arranged in rungs between rails. | Exact equipment placement and wire routing. | A controls technician tracing the conditions for an output. |
| Logic | Gates and the relationships between logical inputs and outputs. | Power wiring, package pin locations, and physical placement unless added. | A digital designer following Boolean decisions through a circuit. |
| Electrical floor plan | Locations of outlets, switches and fixtures on a building plan, interpreted with its legend. | Internal circuit operation; complete routing may be on other drawings. | An installer or building designer locating devices within rooms. |
| Riser | Distribution between building levels and the equipment serving them. | Detailed room layouts and exact conduit paths unless specified. | A building electrical designer or installer coordinating distribution across floors. |
Read the drawing title, legend, revision, and notes before treating a line or mark as an instruction. The same habit applies to mechanical drawings; see Choosing Drawing Views and The Alphabet of Lines.
Compare one circuit in pictorial, wiring, and schematic views; Interactive
Compare one circuit in pictorial, wiring, and schematic views
This teaching example connects a battery, switch, resistor, and LED in one loop. The resistor is in series with the LED. The drawings explain identity and connections; they do not specify a buildable parts list, resistor value, battery rating, or package pinout.
Choose a view. Choose a component to keep it marked when you change views.
Pictorial view
Wiring view
Schematic view
Block view
The wiring view retains every terminal connection. The block view deliberately removes that detail to explain each part's job. The schematic retains those connections while replacing part pictures with common symbols. Compare the three drawings together, or select one view to trace a part. On narrow screens the comparison stacks vertically.
For the electrical quantities and circuit behavior, continue to Current, Voltage, and Resistance, Series and Parallel Circuits, and AC and DC. For programmable control, see Microcontroller Basics. For work on real equipment, use Electrical Safety.
A layout, floor plan, and riser answer different location questions
A layout, floor plan, and riser answer different location questions
A PCB footprint is the land pattern where a component attaches to a board. Traces are the board's conductive paths. An IC is a chip; its internal layout is not the same drawing as the board that holds it.
A floor plan places devices in rooms. Its legend tells you what each mark means. A riser makes the relationship between building levels easier to follow. Neither should be treated as a complete installation instruction by itself.
Read control logic without assuming physical placement
Read control logic without assuming physical placement
A ladder diagram arranges control conditions and outputs in horizontal rungs between two vertical rails. A relay drawing and a PLC program may use a similar ladder shape, but a PLC instruction tests a stored state; it is not a picture of a physical contact.
A logic diagram emphasizes operations such as AND, OR, and NOT. It helps answer which combinations of inputs produce an output. The diagram may omit supply connections and package pin numbers, so it does not replace a wiring drawing.
Practice selecting a useful drawing; Practice
Practice selecting a useful drawing
Continue with Reading Electrical Connections to recognize common component symbols, distinguish a joined wire from a crossing, and count electrical nodes.