# Circuit diagram

Circuit diagrams need a real symbol set: a resistor drawn as a rectangle with no standard notation is just a rectangle. Both the draw.io electrical libraries and TikZ's circuitikz give you correct symbols.

Which to pick depends on whether the schematic will be edited by hand or generated alongside a document.

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## When to reach for one

* Hardware documentation and design notes.
* Teaching material where the symbols themselves are the subject.
* Explaining a circuit in an engineering wiki without attaching a CAD file.

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## How to draw it in Capable

| **Route** | **Use when**                                  |
| --------- | --------------------------------------------- |
| draw.io   | Electrical shape libraries, laid out by hand. |
| TikZ      | LaTeX-quality schematics generated from text. |

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## Symbols you will reach for

* Passive components: resistors, capacitors, inductors, with values.
* Active components: diodes, transistors, op-amps, with part numbers.
* Power and ground, with the correct ground symbol for the context.
* Connectors and test points, labelled to match the physical board.

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## A few things that catch people out

* Ground symbols are not interchangeable; earth, chassis and signal ground mean different things.
* Label component values. A schematic without values documents topology only.
* For anything that will be manufactured, the diagram supplements the CAD file rather than replacing it.

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## Related

[Wiring and cable diagramConnectors, pinouts, colours and gauges.](https://help.gocapable.com/diagrams/wiring-and-cable-diagram.html)

[Digital timing diagramWaveforms, clocks and bus transitions.](https://help.gocapable.com/diagrams/digital-timing-diagram.html)

[ExamplesWorking diagrams you can copy.](https://help.gocapable.com/diagrams/examples.html)

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_Approximately right is wrong here._