> For the complete documentation index, see [llms.txt](https://docs.echook.uk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.echook.uk/circuit-schematics.md).

# Circuit Schematics

This section explains the circuits on the PCB for the V1.3 board, and how each signal is adapted to one that the Arduino can read. The full schematic is shown below.

If you're building a kit, this section is mainly for understanding how it works. You have already soldered these components in the *Build Instructions* section.

![](https://lh6.googleusercontent.com/SXjFbX8bDlfKE0VODAfj_d66mGtRyzMlGTBV3yTJdEY_7hOw0RdNYhe0L4ZAfgwq7jyyWLpS7EBbUkiAnd-zgr9pi21ULzmu6KMaitzdlwpdrJA6QmWo774MKbJcPVKEzIg_H0lN)

For V2 boards the schematic and PCB files are available in [KiCad](https://www.kicad.org/) format for newer versions, and in [DesignSpark PCB](https://www.rs-online.com/designspark/home) format for legacy files. Both are free software formats, and the files are available at [github.com/eChook](https://github.com/eChook/eChook_Nano_PCB).