要将符号摆放到原理图中，可以使用图标 或者快捷键 A 。 出现选择符号对话框，让您选择要添加的符号。 符号按符号库分组。

默认情况下，仅显示符号/库名称和描述列。 可以通过右键单击列标题并选择“选择列”来添加其他列。

The Choose Symbol dialog filters symbols by name, keywords, description, and all additional symbol fields according to what you type into the search field. You can choose to sort search results alphabetically or by best match by clicking on the button.

有一些高级筛选器可用：

如果符号指定了一个默认的封装，这个封装将在右下方预览。如果符号包括封装过滤器，可以在右边的封装下拉菜单中选择满足封装过滤器的备用封装。

选择一个要放置的符号后，该符号将被吸附在光标上。 左键点击原理图中所需要摆放的位置，将符号放入原理图中。在将符号放入原理图之前，可以通过快捷键或右键菜单来旋转、镜像或编辑它的字段。这些操作也可以在放置后进行。

如果 放置重复副本 选项被选中，在放置一个符号后 KiCad 将开始放置该符号的另一个副本。这个过程一直持续到用户按下 Esc。

对于有多个单元的符号，如果 放置所有单元 选项被选中，在放置符号后 KiCad 将开始放置该符号中的下一个单元。 这将持续到最后一个单元被放置或用户按下 Esc。

电源符号是代表与电源网络连接的符号。 这些符号被分组在 power 库中，所以可以使用符号选择器来放置。 然而，由于电源的放置很频繁， 工具是可用的。这个工具使用方法类似，只是搜索是直接在 power 库和其他包含电源符号的库中进行。

符号可以用移动（M）或拖动（G）工具移动。这些工具将作用于选定的符号，如果没有选定符号，则作用于光标下的符号。

移动 工具移动符号本身，而不保持与符号引脚的导线连接。

拖动 工具在移动符号时不会破坏其引脚的导线连接，因此也会移动连接的导线。

你也可以用鼠标点击并拖动符号，这取决于偏好设置中 鼠标和触摸板 部分的 左键拖动手势 设置。

符号也可以旋转（R）或在X（X）或Y（Y）方向上进行镜像。

符号的字段可以在符号的属性窗口中进行编辑。用快捷键 E 或通过双击符号来打开符号属性窗口。

The Symbol Properties window displays all the fields of a symbol in a table. New fields can be added, and existing fields can be deleted, edited, reordered, moved, or resized. Fields can be arbitrarily named, but names beginning with ki_, e.g. ki_description, are reserved by KiCad and should not be used for user fields.

每个字段的名称和值可以是可见的或隐藏的，并且有几个格式化选项：水平和垂直对齐、方向、位置、字体、文本颜色、文本大小和黑体/斜体。字段的自动放置也可以在每个字段的基础上启用。显示位置始终针对正常显示的符号（无旋转或镜像）指示，并且与符号的锚点相关。

The Update Symbol from Library…​ button is used to update the schematic’s copy of the symbol to match the copy in the library. The Change Symbol…​ button is used to swap the current symbol to a different symbol in the library. These functions are described later.

编辑符号…​ 打开符号编辑器，编辑原理图中的符号副本。注意，库中的原始符号将不会被修改。编辑库中的符号…​ 按钮可以打开符号编辑器来编辑库中的原始符号。在这种情况下，原理图中的符号将不会被修改，直到用户点击 更新库中的符号…​ 按钮。

符号有几个属性，它们会影响 KiCad 其他部分对符号的处理方式。

从仿真中排除 防止该符号被包括在 SPICE 模拟中。

从 BOM 中排除 防止该元件被包括在BOM 导出中。

从电路板中排除 意味着该符号仅用于原理图，相应的封装不会被添加到 PCB 上。

不安装 意味着该元件不应该被安装到 PCB 上，虽然相应的封装仍然应该被添加到电路板上。如下图所示，DNP 符号在原理图中显示为不饱和状态，上面有一个红色的 "X"。

When a symbol is added to the schematic, KiCad embeds a copy of the library symbol in the schematic so that the schematic is independent of the system libraries. Symbols that have been added to the schematic are not automatically updated when the library changes. Library symbol changes are manually synced to the schematic so that the schematic does not change unexpectedly.

To update symbols in the schematic to match the corresponding library symbol, use Tools → Update Symbols from Library…​, or right click a symbol and select Update Symbol…​. You can also access the tool from the symbol properties dialog.

The top of the dialog has options to choose which symbols will be updated. You can update all symbols in the schematic, update only the selected symbols, or update only the symbols that match a specific reference designator, value, or library identifier. The reference designator and value fields support wildcards: * matches any number of any characters, including none, and ? matches any single character.

The middle of the dialog has options to control what parts of the symbol will be updated. You can select specific fields to update or not update, which properties of the fields to update (text, visibility, size and style, and position), and how to handle fields that are missing or empty in the library symbol. You can also choose whether to update symbol attributes, such as do not populate and exclude from simulation / bill of materials / board.

The bottom of the dialog displays messages describing the update actions that have been performed.

To change an existing symbol to a different symbol, use Edit → Change Symbols…​, or right click an existing symbol and select Change Symbol…​. This dialog is also accessible from the symbol properties dialog.

The options for the Change Symbols dialog are very similar to the Update Symbols from Library dialog.

Another way to swap existing symbols for new ones is to use Tools → Edit Symbol Library Links…​. This dialog contains a table of every symbol in the design, grouped by current library symbol. By choosing a new symbol in the New Library Reference column, you can make all instances of the existing symbol instead point to the new symbol. If the Update symbol fields from new library option is used, the contents of the existing symbols' fields will be updated to match the new symbols' fields.

The Map Orphans button attempts to automatically remap orphaned symbols to symbols with the same name in an active library. For example, if there is a symbol with the current library reference mylib:symbol123, but the mylib library cannot be found, the Map Orphans button will attempt to find a symbol named symbol123 in any of the libraries that are present. This button is only enabled if orphaned symbols are present in the schematic (see the legacy schematics section).

This dialog is primarily useful for managing symbols that appear in multiple libraries, when you want to switch from one library to another. For example, if a schematic uses symbols that are in both a global library and a project-specific library, the Symbol Library References dialog could be used to switch between using the global symbols or the equivalent project-specific symbols. It does not have features for fine-grained control of how fields are updated; for that, use the Change Symbols dialog.

符号字段表允许你在电子表格界面中查看和修改所有符号的字段值。你可以用 按钮打开符号字段表。

Cells are navigated with the arrow keys, or with Tab / Shift+Tab to move right / left and Enter to move down, respectively.

通过点击和拖动可以选择一个单元格范围。选定的整个单元格范围可以通过（Ctrl+C）或（Ctrl+V）进行复制或粘贴。从表中复制单元格的对于创建 BOM 非常有用。下面将介绍复制和粘贴单元格的更多细节。

Any symbol field can be shown or hidden using the Show checkboxes on the left or by right-clicking on the header of the table. New symbol fields can be added using the button; a field with that name will be added to every symbol. Each field can have its own label, which doesn’t have to be the same as the field name, and is used as the column header. Fields can be renamed with the button or deleted with the button.

Several virtual fields are available in this dialog that do not directly represent symbol fields. Adding a field with one of the following names will not create a new field in the symbols, but will create a special column in the table with auto-generated values for each symbol:

Similar symbols can optionally be grouped by any symbol field using the Group By checkboxes. Symbols are grouped into a single row in the table if all of their Group By fields are identical. The grouped row can be expanded to show the individual symbols by clicking the arrow at the left of the row. The Group Symbols checkbox enables or disables symbol grouping, and the button recalculates groupings.

Presets are available to configure the list of fields. Presets store which fields are displayed, which fields are used for grouping, and the column order. You can create and save your own presets or use one of several default presets. Custom presets can be deleted in this dialog or in the Schematic Setup dialog.

Symbols can be filtered by reference designator using the Filter textbox at the top. The filter supports wildcards: * matches any number of any characters, including none, and ? matches any single character. You can also change the display scope, showing only symbols in the current sheet, the current sheet and all of its subsheets, or the entire project. Symbols with the DNP (do not populate) attribute set can be optionally excluded by checking the Exclude DNP box.

You can cross-probe from this dialog by selecting a row in the table. Depending on the Cross-probe action setting at the bottom of the dialog, this can highlight the corresponding symbol in the schematic, select the corresponding symbol in the schematic, or do nothing. The selection action can also select the symbol’s footprint in the board editor, depending on the PCB Editor cross-probing settings.

The Symbol Fields Table is also a bill of materials tool. You can use the Export button to save the symbol fields to an external file. The fields are exported to the BOM exactly as they are currently shown in the spreadsheet view. File format settings are configured in the Export tab. For more information about exporting a BOM, see the BOM tool documentation.

启用自动批注后，符号被添加到原理图中时将被自动批注。你可以在 偏好设置 中 原理图编辑器 → 批注选项 窗格中选中 自动批注符号 复选框来启用自动批注。自动批注也可以通过左侧工具栏的 按钮进行切换。

当同时添加多个符号时，它们会根据 顺序 设置进行批注，按 X 或 Y 位置排序。

编号 选项为新的位号设置起始编号。 可以是最小的可用数字，也可以是基于原理图页码的数字。

关于批注选项的更多信息，请参见批注工具的文档。

批注工具会自动为原理图中的符号指定位号。要启动批注工具，请点击顶部工具栏上的 按钮。

该工具提供了几个选项来控制符号的批注方式。

范围： 选择批注是否适用于整个原理图、仅适用于当前原理图或仅适用于选定的符号。如果选择了 递归到子原理图 的选项，所选范围内子原理图中的符号将被重新批注；否则子原理图中的符号将不会被重新批注。例如，如果同时选择递归到子原理图 和 仅选择，所有选定范围内子原理图中的符号将被重新批注。

Options: Selects whether annotation should apply to all symbols and reset *existing reference designators, or apply only to unannotated symbols.

顺序： 选择编号的方向。如果符号按 X 位置排序，原理图页面左侧的所有符号将比页面右侧的符号编号小。如果符号按 Y 位置排序，则原理图顶部的所有符号的编号将小于原理图底部的符号的编号。

编号： 选择位号的起始编号。每一个位号都会选择在起始编号之上的最小的未使用的数字。起始编号可以是一个任意的数字（通常是 0），也可以是原理图页码乘以 100 或 1000，这样每个元件的位号就与它所在的原理图页相对应。

清除批注 按钮可以清除所选范围内的所有位号。

批注信息可以用底部的复选框进行过滤，或用 保存…​ 按钮保存到报告中。

导线用于在两点之间直接建立电气连接。 要建立连接，必须将一段导线的末端与另一段导线或一个引脚相连。只有导线的末端才能建立连接；如果一根导线穿过另一根导线的中间，不会建立连接。

未连接的导线端有一个小方块，表示连接点。 当连接到导线端时，这个方块就会消失。未连接的引脚有一个圆圈，连接完成时时也会消失。

标签是用来给导线和引脚分配网络名称的。具有相同网络名称的导线被认为是连接在一起的，所以标签可以用来进行连接，而不需要直接画线连接。

A net can only have one name. If two different labels are placed on the same net, an ERC violation will be generated. Only one of the net names will be used in the netlist. The final net name is determined according to the rules described below.

有三种类型的标签，每种都有不同的连接范围。

总线是一种在原理图中分组相关信号的方法，以简化复杂的设计。 总线可以像导线一样用总线工具画出来 ，并像信号线一样用标签命名。

在下面的原理图中，许多引脚都连接到总线上，也就是中间的蓝色粗线。

Power symbols are symbols that are conventionally used to represent a connection to a power net, such as VCC or GND. Power symbols are virtual: they do not represent a physical component on the PCB.

In addition to being a visual indicator that the attached net is a power rail, power symbols make global connections: two power symbols with the Value connect to each other anywhere in the schematic, regardless of sheet. The power symbol’s Value field determines the name of the attached net.

在下图中，电源符号用于将电容器的正负极分别连接到 VCC 和 GND 网络上。

In the KiCad standard library, power symbols are found in the power library, but power symbols can be created in any library. Creating custom power symbols is described in the symbol editor documentation. Instead of making a new symbol, you can also modify an existing power symbol in the schematic: changing its Value field will change the net the power symbol connects to.

原理图中的每个网络都被分配了一个名称，无论这个名称是由用户指定还是由 KiCad 自动生成。

当多个标签附加到同一个网时，最终的网络名将按以下顺序确定，从最高优先级到最低：

如果一个网络有多个同一类型的标签，则按字母顺序排序，使用第一个。

如果一个网络经过层次的多张原理图，它的名字将取决于层次结构中优先级最高的标签。通常，局部标签优先级高于层次标签。

如果以上标签类型都没有添加到网络中，那么网络的名称将根据连接的符号引脚自动生成。

上面的截图中可以看到两个 PWR_FLAG 符号。它们向 ERC 表明，两个电源网络 VCC 和 GND 实际上连接到一个电源上，虽然没有明确的电源输出（如电压调节器输出）连接到以上两个网络。

如果没有这两个标志，ERC 工具会诊断出：错误：输入电源引脚没有被任何输出电源引脚驱动。

PWR_FLAG 符号可以在 power 符号库中找到。将任何电源输出引脚连接到网络上，可以达到同样的效果。

No-connection flags () are used to indicate that a pin is intentionally unconnected. These flags prevent "unconnected pin" ERC warnings for pins that are intentionally unconnected. Also, while symbol pins that are stacked on top of each other are normally connected to the same net, if a no-connection flag is added to the stacked pins they will instead be connected to separate nets.

Note that no-connection flags are distinct from the "unconnected" symbol pin type, although they both prevent "unconnected pin" ERC warnings on the pin in question and prevent stacked pins from connecting to each other.

When the power pins of a symbol are visible, they must be connected, as with any other signal. However, symbols are sometimes drawn with hidden power input pins, which are connected implicitly. KiCad automatically connects invisible pins with type Power Input to a global net with the same name as the pin. For example, if a symbol has a hidden power input pin named VCC, this pin will be globally connected to the VCC net on all sheets. This kind of implicit connection is not recommended in new designs.

网络类在 原理图设置 对话框的 网络类 面板中管理。

顶部的窗格列出了设计中存在的网络类。默认 网络类总是存在的，你可以通过 按钮添加额外的网络类，或者通过 按钮删除选定的网络类。

每个网络类可以有独特的图形属性，它决定该网络类的导线如何在原理图中显示。导线和总线的厚度、颜色和线条风格（实线、虚线、点线等）都可以调整。将颜色设置为透明将使用主题的默认导线/总线颜色，该颜色可在偏好设置中配置。

您还可以为每个网类设置电路板设计规则，但默认情况下 DRC 字段是隐藏的。 右键单击标题行以显示或隐藏其他列。 有关设置网络类设计规则的更多信息，请参阅 PCB editor documentation。

底部窗格列出了基于模式的网络类分配。 每行都有一个网络名称模式和一个网络类； 名称与模式匹配的网络被分配给指定的网络类。 如果网络匹配多个模式，则使用第一个匹配项。 基于模式的网络类分配是动态的：当添加与现有模式匹配的新网络时，它将自动分配给关联的网络类。 网络模式可以使用通配符（ * 匹配任意数量的任意字符，包括无字符，以及 ? 匹配任意字符）和 正则表达式 。匹配所选模式的网络显示在模式列表的右侧。

例如, net* 模式匹配名为 net , net1, network, 和任何其他以 net 开头的网络名称的网络。 因为 * 在正则表达式中的含义略有不同（* 匹配零个或多个前面的字符）, net* 模式也匹配名为 ne 的网络。

使用 按钮来添加网络类分配模式，或 按钮来删除模式。

Instead of adding netclass patterns in the Schematic Setup dialog, you can directly create netclass patterns from the schematic canvas. Right click a net and select Assign Netclass…​ to bring up the Add Netclass Assignment dialog. The netclass pattern is pre-filled with the name of the selected net, but the pattern can be changed if desired. All nets matching the pattern are displayed in the dialog. This method can only be used on nets with an assigned name.

作为基于模式的网络类分配的替代方法，网络类可以用 网络类标识符 或 标签 以图形方式分配给原理图中的网络。网络类必须在原理图设置中创建，然后才能以图形方式分配。

在下面的图片中，一个网络类标识符被用来给 50R 网络类分配信号。

网络类标识符通过右侧工具栏的 按钮添加的。网络类标识符除了不能被用来命名网络之外，行为类似于标签。根据标识符的 网络类 字段的值，与标识符关联的网络被分配了一个网络类。`网络类`字段提供了设计中所有网络类的下拉列表。

如果一个标识符被附加到一个总线上，总线上的所有成员都被分配到指定的网络类。

除了相关的网络类，你还可以在标识符的属性中编辑标识符的形状（点、圆、菱形或矩形）、方向、引脚长度 和 颜色。

也可以用网络标签给网络分配网络类，方法是在标签中添加一个 网络类 字段。

如果一个网络被图形化分配了两个不同的网络类，ERC 将报告一个问题。图形化的网络类分配优先于基于模式的分配：如果一个网络与网络类模式分配相匹配，并且也有一个图形化的网络类分配，那么将使用图形化的网络类分配。

You can show or hide netclass directives in the schematic using the View → Show Netclass Directives option.

Two kinds of text can be added to schematics, which are referred to as text () and text boxes (). Both are added using their respective buttons in the right toolbar. Text boxes are similar to regular text except that they have an optional border and they automatically reflow text within that border.

这两种文本项目都支持多行文本和基本的格式设置功能，文本框还可以将文本换行以适应文本框外框，并有额外的格式选项。所有的文本都有可调整的字体、颜色、大小、黑体和斜体，左右对齐，以及垂直和水平方向。文本框还支持水平居中，垂直对齐选项，以及彩色边框和填充。

Graphic rectangles (), circles (), arcs (), and lines () can all be added using their respective buttons in the right toolbar.

线宽、颜色和样式（实线、虚线或点线）可以在每个图形（E）的属性对话框中进行配置。矩形、圆形和弧形也可以设置填充颜色并去除其轮廓线。

将形状的线宽设置为 0，则使用原理图的默认线宽，该线宽可在 <schematic-setup,原理图设置>> 中配置。虚线的间距也可以在那里配置。移除线条或填充物的颜色将会使用颜色主题的图形颜色，这可以在 偏好设置 中配置。

与导线一样，图形的线条服从线条的绘制模式设置（90 度，45 度，或自由角度），可以用左侧工具栏的切换按钮来设置 (, , and )。 Shift+Space 循环切换这些模式。

与 PCB 布线一样 ，/ 快捷键切换线条模式。

位图图像可以通过 按钮添加到原理图中。原理图中的图像可以被移动和缩放。属性对话框允许设置位置和比例，以及将图像转换为灰度。

文本和图形的属性可以通过 编辑文本和图形属性 对话框（工具 → 编辑文本和图形属性…​）进行批量编辑。该工具还可以修改导线和总线的视觉属性。

标题栏是用页面设置工具（）编辑的。

可以编辑标题栏中的每个字段，以及纸张大小和方向。 如果为某个字段选中了 导出到其他原理图页 选项，则该字段将在所有原理图页的标题栏中更新，而不仅仅是当前原理图页。

你可以用 发布日期 旁的左箭头按钮将日期设置为今天或其他任何日期，但原理图中的日期不会自动更新。

也可以选择一个原理图模板文件。

原理图页码（页面X/Y）会自动更新，也可以用 编辑 → 编辑原理图页码…​ 手动设置。

格式化面板包含符号、文本、标签、图形和导线的外观设置。

符号单元表示法 设置多单元符号的每个单元在其位号中的引用方式。 默认情况下，每个单元的不同字母会添加到到没有分隔符的位号后，例如符号 U1 的第二个单元为 U1B ，但这可以更改。 可以使用数字代替字母，并且可以在符号的位号和单元标识符之间使用各种分隔符（.、-、_ 或无）。

Default text size sets the default text height used by the text, text box, and label tools. Overbar offset ratio controls the vertical spacing between text and an overbar (~{}) over that text, as a ratio of the text height. Label offset ratio controls the vertical spacing between a local label’s text and the attached wire, relative to the label’s text size. This also affects the spacing between symbol pins and their pin number. Global label margin ratio defines the size of the box around a global label, relative to the global label’s text size. Increasing the margin may be useful to avoid overlapping text with overbars (~{}) or letters with descenders, but this may cause closely packed global labels to overlap with each other.

如果符号不覆盖默认线宽，默认线宽 设置定义了符号图形的默认线宽。 引脚符号大小 缩放符号引脚图形样式标注，例如倒置引脚上的气泡。

Junction dot size sets the schematic’s default wire junction dot size. The default size can be overridden by editing an individual junction dot’s properties. Connection width specifies the grid size used for the Symbol pin or wire end off connection grid ERC check. Schematics typically use a 50 mil grid for electrical connections, so this should usually remain set at 50 mils.

The Operating Point Overlay settings configure how operating point simulation results are displayed on the schematic canvas. The significant digits settings control the number of significant digits printed on voltage and current overlays. The range settings control the units used to display voltage and current measurements.

显示页面间引用 启用或禁用 页面间引用 的显示，它是全局标签旁边的页码列表，链接到原理图中相同名称全局标签出现的位置。 显示当前页面引用 控制当前页面是否包含在页码列表中。 标准 和 缩略 确定是显示完整的页码列表还是仅显示第一页和最后一页的页码。 前缀 和 后缀 字段在页码列表前后添加可选字符。 在下面的页面间引用图例中，分别添加了 [ 及 ] 的前缀和后缀。

虚线外观在格式部分中控制。 虚线长度 控制破折号的长度，而 间隙长度 控制破折号和点之间的间距。 破折号和间隙长度是相对于线宽的：间隙长度为 2 则表示线宽的两倍。

字段名称模板是空的符号字段，会自动添加到原理图中的所有符号。 当原理图中的每个符号都需要在符号中定义的默认字段之外的其他字段时，这可能很有用，例如制造商部件号的字段。

模板字段可以设置为可见或不可见，也可以设置为URL 字段。

在原理图设置中定义的字段名称模板仅适用于当前项目。 字段名称模板也可以在偏好设置中定义，它适用于在您的计算机上编辑的所有项目。

BOM presets are saved configurations for the Symbol Fields Table and BOM export tool. There are two types of presets. BOM presets configure which fields are displayed in the symbol fields table, which order they are displayed in, and how they are used to group symbols. These fields are also directly used in the BOM output. BOM formatting presets configure the output BOM file format, including which separator characters are used to separate fields. Both types of presets are created in the Symbol Fields Table, but can are listed and can be deleted here.

违规严重性 面板可让您配置应将哪些类型的 ERC 消息报告为错误、警告或忽略。

引脚冲突映射 允许您配置连接规则，以根据相互连接的引脚类型定义错误和警告的电气条件。 例如，默认情况下，当输出引脚连接到另一个输出引脚时会产生错误。

这些面板在 [ERC - 配置，ERC 章节] 中有更详细的解释。

网络类 面板允许您管理项目的网络类，并使用模式将网络分配给网络类。 在此面板中管理网络类等同于在 电路板设置对话框 管理它们。 也可以使用带有 [网络类 - 标识符，网络类标识符]或 [标签 - 网络类，网络标签] 的图形分配方法将网络分配给原理图中的网络类。

基于模式的网络类分配在 网络类章节 中有更详细的解释。

总线别名定义 面板允许您创建总线别名，这是总线中信号组的名称。 有关总线别名的更多信息，请参阅 [总线-别名，总线别名文档]。

文本替换变量可以在文本变量部分创建。 这些变量允许您用变量名替换任何文本字符串。 这种替换发生在变量名称在 ${VARIABLENAME} 的变量替换语法中使用的任何地方。

例如，您可以创建一个名为 VERSION 的变量并将文本替换设置为“1.0”。 现在，在 PCB 上的任何文本对象中，您可以输入 ${VERSION}，KiCad 将其替换为 1.0。 如果将文本替换更改为 2.0，则包含 ${VERSION} 的每个文本对象都将自动更新。 您还可以混合使用常规文本和变量。 例如，您可以使用文本 Version: ${VERSION} 创建一个文本对象，它将被替换为 Version: 1.0。

文本变量也可以在 电路板设置中创建。 文本变量是项目范围的； 在原理图编辑器中创建的变量在电路板编辑器中也可用，反之亦然。

还有一些内置系统文本变量。

Modern versions of KiCad can open schematics created in versions prior to KiCad 6.0, but the cache library file (<projectname>-cache.lib) must be present to load the schematic correctly.

Since version 6.0, KiCad stores all symbols used in a project in the schematic. This means that you can open a schematic made in KiCad 6.0 or later on any computer, even if the libraries used in the project are not installed or have changed. Modern KiCad schematic files use the .kicad_sch extension.

Prior to version 6.0, KiCad did not store symbols in the schematic. Instead, KiCad stored references to the symbols and their libraries. It also stored a copy of every symbol used by the project in a separate cache library file (<projectname>-cache.lib). As long as the cache library was included with the project, the project could be distributed without the system library files, because KiCad could load any needed symbols from the cache library as a fallback if the libraries referenced in the schematic were missing. Legacy KiCad schematic files use the .sch extension.

When you open a legacy schematic, KiCad will look in the cache library to find all of the symbols used in the schematic in the cache library. When you save the legacy schematic, KiCad will save it as a new file in the modern schematic format (.kicad_sch), with the necessary symbols embedded in the schematic itself. The original legacy schematic and the cache library will remain, unmodified, but they are no longer necessary once the schematic has been saved in the modern format.

When you open a legacy schematic, KiCad may display the Project Rescue Helper dialog. This means that one or more symbols in the cache library do not match the corresponding symbol in the external library. The dialog helps you "rescue" symbols from the cache library into your schematic, if desired. You can also open the rescue dialog at any time using Tools → Rescue Symbols…​. The cache library file must be present in order to use the rescue tool.

The rescue dialog lists all symbols that don’t match between the cache library and the external symbol library. The discrepancy can be because:

For each symbol in the list, selecting the symbol displays the reference designator and value for each instance of the symbol, and shows a visual preview of the symbol. If a corresponding symbol exists in the system symbol library, the dialog shows both copies of the symbol for comparison. If the symbol only exists in the cache library, the dialog only shows the cached symbol.

In this example, the project originally used a diode with the cathode facing left, but the library now contains one with the cathode facing right. This change would break the design, so it would be important to use the cached symbol as the original designer intended.

Pressing Rescue Symbols here will cause the selected symbols from the cache library to be saved into a special rescue library (<projectname>-rescue.kicad_sym). The corresponding symbols in the schematic will be updated to use the newly rescued symbols. Any unselected symbols will not be rescued, but their symbol linkage can be updated in the schematic later.

Alternatively, pressing Skip Symbol Rescue will exit the dialog without rescuing any symbols. KiCad will use the versions of the symbols found in the external libraries. You can run the rescue function again with Tools → Rescue Symbols…​, or manually edit symbol linkage in the symbol’s properties.

If you would prefer not to see this dialog, you can press Never Show Again. This has the same effect as pressing Skip Symbol Rescue for the current schematic and all future schematics.

If a symbol in a legacy schematic cannot be found in either the cache library or the external library, KiCad cannot rescue that symbol. A placeholder symbol is inserted into the schematic in its place, as shown below.

You can attempt to remap these orphaned symbols using the Change Symbols or Edit Symbol Library Links dialogs, but either option may require manual corrections to the schematic. These tools are explained in more detail in the Updating and exchanging symbols section.

Modern versions of KiCad can open schematics created in versions prior to KiCad 5.0, but you will need to go through a symbol remapping process to open the schematic without losing symbol information.

Since version 5.0, KiCad schematics refer to specific symbols using both the symbol and library name. Even if multiple libraries each contain a symbol with the same name, the designer’s intended symbol is unambiguously specified.

Prior to version 5.0, KiCad schematics stored only the symbol name, not the library name. Symbols in the schematic were indirectly mapped back to the original library by searching through the project’s library list for a matching symbol. When you open a pre-5.0 schematic, KiCad will attempt to automatically "remap" the symbols so that each bare symbol name is replaced with a fully-specified symbol library and symbol name pair. The original schematics will be backed up in a rescue-backup folder.

You can skip the automatic remapping, but you will need to remap the symbols yourself using the Change Symbols dialog. You can also re-run the Remap Symbols tool using Tools → Remap Legacy Library Symbols…​.

原理图之间的电气连接是通过 标签进行的。在 KiCad 中，有几种标签，每种都有不同的连接范围。

在子原理图内放置层次标签后，可以在父原理图内的子原理图符号上添加匹配的 层次原理图引脚。然后，你可以用导线、标签及总线与层次原理图引脚进行连接。子原理图符号中的层次原理图引脚与子原理图中匹配的层次化标签相连。

对于子原理图中的每一个层次化标签，可以通过点击右侧工具栏中的 按钮，然后点击原理图页面符，将相应的层次化标签导入原理图页面符中。第一个与层次化标签匹配的层次化引脚将附在光标上，可以将它放在原理图页面符边界的任何地方。再次点击该工具将继续导入更多的层次原理图引脚，直到没有更多的层次化标签需要从子原理图中导入。层次原理图引脚也可以通过在原理图页面符的右键菜单中选择 导入层次原理图引脚 来导入。

你可以在原理图页面引脚属性对话框中编辑页面引脚的属性。 通过双击原理图页面引脚，或选择页面引脚并使用快捷键 E ，或者右击原理图页面引脚并选择 属性…​ 来打开这个对话框。

原理图页面引脚的 名称 可以在文本框中编辑，也可以从子原理图的层次化标签的下拉列表中选择。原理图页面引脚的名称必须与子原理图中相应的层次化标签相匹配，所以如果页面引脚的名称被改变，标签也必须改变。

形状 区域可以改变页面引脚的形状，但没有电气效果。它可以被设置为输入、输出、双向、三态或无源。 引脚的*字体*、文本大小、*颜色*和强调（粗体或斜体）也可以 被改变。

一个简单的层次结构的例子是 KiCad 包含的 video 演示工程。根原理图包含七个独特的子原理图，每个子原理图都有层次化标签和原理图页面引脚，将子原理图与根原理图相互连接。下面是其中两个子原理图的页面符。

复杂的层次结构 演示工程是一个复杂层次结构的例子。 根原理图包含两个子原理图页面符，它们都指向同一个原理图文件（ampli_ht.kicad_sch）。这使得设计中包含了同一个放大器电路的两个副本。尽管这两个原理图页面符指向同一个文件名，但原理图的名称是唯一的（ampli_ht_vertical 和 ampli_ht_horizontal）。在每个子原理图内，除了位号外，其他的电路都是相同的，而位号也是唯一的。

这个工程不包含原理图层次引脚连接。根原理图和子原理图之间的唯一连接是用电源符号进行的全局连接。如果设计需要，复杂层次结构中的原理图可以包括原理图层次引脚的连接。

flat_hierarchy 演示工程是一个扁平化层次结构的例子。根原理图包含两个不同的子原理图页面符，没有层次化原理图引脚。在这个工程中，根原理图除了容纳子原理图外没有任何作用，子原理图只是作为原理图中的附加页使用。

在上面的截图中，有三个错误。

选择一个 ERC 标记会在窗口底部的信息窗格中显示违规描述。

如下面的例子所示，在电源引脚上出现 "输入电源引脚未被任何输出电源引脚驱动" 的错误是很常见的，即使电源引脚似乎正确地连接到电源导线。这种情况发生在通过连接器或其他没有被标记为电源输出的元件提供电源的设计中。在这些情况下，ERC 不会检测到任何连接到网络的输出电源引脚，而会判断输入电源引脚没有被电源驱动。

为了避免这个警告，可以将类似的电源网络连接到 PWR_FLAG 符号上，如下例所示。PWR_FLAG 符号可以在 power 符号库中找到。当然，也可以将任意电源输出引脚连接到该网络；PWR_FLAG 只是一个具有单一电源输出引脚的符号。

接地网络通常也需要一个 PWR_FLAG，因为电压调节器的输出被声明为电源输出，但其接地引脚通常被标记为电源输入。因此，除非使用 PWR_FLAG 符号，否则地线可能看起来没有与电源相连。

关于电源引脚和电源标志的更多信息，请参见PWR_FLAG 文档。

原理图设置中的 违规严重性 面板让你配置哪些类型的 ERC 应被报告为错误、警告或忽略。

原理图设置中的 引脚冲突映射 面板允许你配置连接规则，根据哪些类型的引脚相互连接来定义错误和警告的电气条件。例如，默认情况下，当一个输出引脚与另一个输出引脚连接时，会产生错误。

可以通过点击矩阵中的方块来改变规则，使其在各种选择中循环：允许、警告、错误。

下表列出了 KiCad 检查的电气规则和每个检查的默认违规严重程度。所有严重程度都是可配置的。

可以通过点击 ERC 对话框中的 保存…​ 按钮来生成和保存 ERC 报告文件。ERC 报告文件的扩展名为 .rpt。下面给出一个 ERC 报告文件的例子。

和单独编辑每个符号的属性相比，符号字段表可以用来在一个地方查看和编辑设计中所有符号的属性。这包括通过编辑每个符号的 封装 字段来分配封装。

符号字段表可以通过 工具 → 编辑符号字段…​，或者通过顶部工具栏上的 按钮进入。

`封装`字段在这里的作用与符号属性窗口的作用相同：可以直接编辑，也可以用封装库浏览器直观地选择封装。

关于符号字段表的更多信息，请参见关于编辑符号属性章节。

下面的图片显示了封装分配工具的主窗口。

顶部的工具条包含以下命令：

下表列出了封装分配工具的键盘命令：

要手动将一个封装与一个元件关联起来，首先在元件（中间）窗格中选择一个元件。然后在封装（右）窗格中选择一个封装，双击所需封装的名称。封装将被分配给选定的元件，而下一个没有分配封装的元件将被自动选择。

当所有的元件都有封装时，点击 OK 按钮来保存分配并退出工具。或者，点击 取消，放弃更新的赋值，或者点击 应用，保存原理图并继续，保存新的赋值，而不退出工具。

封装分配工具允许你在一个外部文件中存储封装分配，并在以后加载这些分配，甚至在不同的工程中。这使你能够自动将符号与适当的封装联系起来。

外部文件被称为等效文件，它存储了一个符号到相应的封装的映射。等效文件通常使用 .equ 文件扩展名。等效文件是具有简单语法的纯文本文件，必须由用户用文本编辑器来创建。语法描述如下。

你可以在 "封装分配工具" 中点击 偏好设置 → 管理 "封装关联文件" 来选择使用哪些等效文件。

相关的环境变量显示在窗口的底部。当 相对 路径选项被选中时，这些环境变量将被自动用于使所选等效文件的路径与项目或封装库相对。

一旦所需的等效文件以正确的顺序载入，就可以通过点击封装分配工具顶部工具栏上的 按钮来进行自动封装分配。

所有在加载的等效文件中找到的符号都将自动分配其封装。然而，已经分配了封装的符号将不会被更新。

封装分配工具包含一个封装查看器。点击顶部工具栏上的 按钮可以启动封装查看器，并显示选定的封装。

顶部的工具条包含以下命令：

左边的工具条包含以下命令：

该工具有几个选项可以控制其行为。

该工具有几个选项可以控制其行为。

通过从 PCB 编辑器中导出 CMP 文件（文件 → 导出 → 封装关联（.cmp）文件…​）并在原理图编辑器中导入（文件 → 导入 → 封装分配…​），也可以将变化从 PCB 同步到原理图。

打印图框： 在打印的原理图中包括图纸的边框和标题块。

输出模式： 以彩色或黑白方式打印原理图。

打印背景色： 包括打印的原理图中的背景色。该选项只在 仅以黑白打印 被禁用时才会启用。

使用不同的颜色主题进行打印： 选择不同的颜色方案进行打印，与在原理图编辑器中选择的显示方案不同。

页面设置…​： 打开一个页面设置对话框，用于设置纸张大小和方向。

预览： 打开一个打印预览对话框。

关闭： 关闭对话框，不打印。

打印： 打开系统打印对话框。

输出目录： 指定保存绘图文件的位置。如果是一个相对路径，它是相对于项目目录创建的。

输出格式： 选择要绘制的格式。有些格式有不同的选项。

页面大小： 设置用于绘制输出的页面大小。这可以被设置为匹配原理图的尺寸或其他页面尺寸。

绘制图框： 在打印的原理图中包括图纸边框和标题块。

输出模式： 设置输出为彩色或黑白。不是所有的输出格式都支持彩色。

颜色主题： 选择用于绘制输出的颜色主题。

绘图背景色： 绘图输出包含原理图背景色。如果输出格式不支持彩色，或者输出模式是黑白，则不会绘制背景色。

Minimum line width: Selects the minimum width for lines.

位置和单位： 设置绘图仪原点和单位。这个选项只 适用于 HPGL 输出。

笔宽： 设置绘图仪的笔宽。这个选项只适用于 HPGL 输出。

Generate property popups: Enables or disables the interactive PDF features described below. This option only applies for PDF output.

绘制后打开文件： 在绘制完成后自动打开绘制的输出文件。

Plotted PDFs can optionally have several interactive features.

The exported BOM will contain exactly the components (rows) and fields (columns) shown in the Edit tab, with the same grouping and sorting. Components with the Exclude from BOM attribute set are shown in the Edit tab but will not be included in the BOM export. Components with the DNP (do not populate) attribute set can be optionally excluded from both the table in the Edit tab and the exported BOM by checking the Exclude DNP box. You can also limit the displayed components to those in the current sheet, the current sheet and all of its subsheets, or the entire schematic.

Fields with the Show box checked will be included as columns in the BOM, and fields with the Group By box checked are used to group components together. Components are grouped into the same line if all of their Group By fields are identical and the Group symbols box is checked. You can set an arbitrary column name for each field and reorder columns by dragging their headers.

Presets are available to configure the list of fields. Presets store which fields are displayed, which fields are used for grouping, and the column order. You can create and save your own presets or use one of several default presets. Custom presets can be deleted in this dialog or in the Schematic Setup dialog.

The built-in presets "Grouped By Value" and "Grouped By Value and Footprint" replicate legacy BOM scripts, while "Attributes" shows only the reference and value fields and the DNP, exclude from board, exclude from simulation, and exclude from BOM attributes.

Some virtual fields are available that may be useful in BOM exports. Adding a field with one of the following names will not create a new field in the symbols, but will create a special column in the table and BOM with auto-generated values for each component:

The functionality of the Edit tab is explained in more detail in the Symbol Fields Table documentation.

The Export tab contains settings concerning the output file format for the BOM and displays a preview of the raw BOM file output.

At the top you can specify the output file. Pressing the Export button will write the BOM to this file path. This path can contain text variables.

The settings on the left control how the BOM information is formatted in the file. You can change the delimiter between fields, the delimiter that surrounds each field, the delimiter that separates a sequence of references (e.g. the comma in R1,R3), and the delimiter for a range of references (e.g. the dash in R1-R3). If no range delimiter is given, ranges will not be used: R1-R3 will be written out as R1,R2,R3, for example, assuming , as a reference delimiter. Tabs and newlines in fields can be preserved or stripped, depending on the Keep tabs and Keep line breaks settings.

Several default format presets are available. You can select a comma-separated value (CSV) format, a tab-separated value (TSV) format, or a semicolon-separated format. You can also create and save your own presets. Custom presets can be deleted in this dialog or in the Schematic Setup dialog.

Previous versions of KiCad used external scripts to process the design information into the desired output format. This BOM generation tool is still available by selecting Tools → Generate Legacy Bill of Materials…​.

Several BOM generator scripts are included with KiCad, and users can also create their own. BOM generator scripts generally use Python or XSLT, but other tools can be used as long as you can specify a command line for KiCad to execute when running the generator.

您可以在 BOM 发生器脚本 列表中选择要使用的 BOM 生成器。 对话框的其余部分显示所选生成器的信息。您可以用 生成器昵称 文本框来改变生成器的显示名称。

右边的窗格显示所选脚本的信息。当生成器被执行时，右边的窗格会显示脚本的输出。

底部的文本框包含了 KiCad 用来执行生成器的命令。当选择脚本时，该文本框会自动填充，但对于某些生成器来说，该命令可能需要手工编辑。当关闭 BOM 工具时，KiCad 会保存每个生成器的命令行，因此定制的命令行会被保留下来。关于命令行的更多细节，请参阅 高级文档。

在 Windows 下，BOM 生成器对话框有一个额外的 *显示控制台窗口*选项。当这个选项未被选中时，BOM 生成器在一个隐藏的控制台窗口中运行，任何输出都会被重定向并打印在对话框中。当该选项被选中时，BOM 生成器在一个可见的控制台窗口中运行，如果生成器插件提供了一个图形用户界面，这可能是必要的。

The PCB Editor can export a BOM through File → Fabrication Outputs → BOM…​. This method provides no control over the output format and does not include all symbol information, but is useful for PCB-only workflows that do not involve a schematic. In general, it is recommended to use the schematic editor’s BOM export tool instead.

网表是通过导出网表对话框（文件 → 导出 → 网表…​）导出的。

KiCad 支持导出多种格式的网表。KiCad、OrcadPCB2、CADSTAR、Spice 和 Spice Model。每种格式都可以通过选择窗口顶部的相应标签来选择。一些网表格式有额外的选项。

点击 导出网表 按钮，会提示输入网表文件名并保存网表。

其他网表格式的自定义生成器可以通过点击 添加生成器…​ 按钮添加。自定义生成器是由 KiCad 调用的外部工具，例如 Python 脚本或 XSLT 样式表。关于自定义网表生成器的更多信息，请参见添加自定义网表生成器章节。

下面是 KiCad 仿真示例的 sallen_key 工程的原理图。

该原理图的 KiCad 格式网表如下：

在 Spice 格式中，网表如下：

第一次运行 KiCad 原理图编辑器时，如果在 KiCad 配置文件夹中没有找到全局符号表文件 sym-lib-table，KiCad 将引导用户设置一个新的符号库表。这个过程将在 初始配置中描述。

符号库只有在它们被添加到全局或工程专用的符号库表中时才能使用。

通过点击 按钮然后选择一个库或点击 按钮然后输入库文件的路径来添加一个库。选定的库将被添加到当前打开的库表中（全局或特定工程）。可以通过选择所需的库条目并点击 按钮来删除库。

The and buttons move the selected library up and down in the library table. This does not affect the display order of libraries in the Symbol Editor or Symbol Chooser.

通过取消选中第一列中的 Active 复选框，可以使库处于非活动状态。非活动状态的库仍然在库表中，但不会出现在任何库的浏览器中，也不会从磁盘加载，这可以减少加载时间。

通过点击范围内的第一个库，然后 Shift - 点击范围内的最后一个库，可以选择一系列的库。

每个库必须有一个独特的名称：在同一个表中不允许有重复的库名称。然而，名称可以在全局和工程库表中重复。工程表中的库比全局表中的同名库优先级更高。

库的名称不一定要与库的文件名或路径有关。冒号字符（:）不能在库的名称或符号名称中使用，因为它被用作名称和符号之间的分隔符。

Each library entry must have a valid path. Paths can be defined as absolute, relative, or by path variable substitution.

The appropriate library format must be selected in order for the library to be properly read. The supported formats are listed above. Only KiCad format libraries (.kicad_sym) can be saved. Other symbol library formats are read-only and must be converted to KiCad format before you can modify them.

有一个可选的描述字段，用于添加库条目的描述。选项字段目前不使用，所以添加选项在加载库时不会有任何影响。

The symbol library tables support path variable substitution, which allows you to define path variables containing custom paths to where your libraries are stored. Path variable substitution is supported by using the syntax ${PATH_VAR_NAME} in the symbol library path.

By default, KiCad defines several path variables which are described in the project manager documentation. Path variables can be configured in the Preferences → Configure Paths…​ dialog.

Using path variables in the symbol library tables allows libraries to be relocated without breaking the symbol library tables, so long as the path variables are updated when the library location changes.

${KIPRJMOD} is a special path variable that always expands to the absolute path of the current project directory. ${KIPRJMOD} allows libraries to be stored in the project folder without having to use an absolute path in the project library table. This makes it possible to relocate projects without breaking their project library tables.

符号库可以全局定义，也可以专门为当前加载的工程定义。在用户的全局表中定义的符号库总是可用的，并存储在用户的 KiCad 配置文件夹中的 sym-lib-table 文件中。工程专用的符号库表只对当前打开的工程文件有效。

每种方法都有其优点和缺点。在全局表中定义所有的库意味着它们在需要时总是可用的。这样做的缺点是，加载时间会增加。

在工程的基础上定义所有的符号库，意味着你只有工程所需的库，这减少了符号库的加载时间。缺点是你总是要记住添加每个工程所需的每个符号库。

一种使用模式是在全局范围内定义常用的库，并在工程专用的库表中定义工程所需的库。对于如何定义库没有任何限制。

Non-KiCad format libraries, including legacy libraries (.lib files), are read-only. They need to be converted to KiCad format (.kicad_sym files) before you can save changes to them.

Libraries in other formats can be converted to KiCad libraries by selecting them in the symbol library table and clicking the Migrate Libraries button. Multiple libraries can be selected and migrated at once by Ctrl-clicking or shift-clicking.

也可以一次转换一个库，方法是在符号编辑器中打开它们并将它们另存为新库。

当加载在符号库表实现之前创建的原理图时，KiCad 将尝试将原理图中的符号库链接重新映射到适当的库表符号。 这个过程的成功与否取决于几个因素：

KiCad provides a symbol editing tool that allows you to create libraries; add, edit, delete, or transfer symbols between libraries; export symbols to files; and import symbols from files. The Symbol Editor can be launched from the KiCad Project Manager or from the Schematic Editor (Tools → Symbol Editor).

一般来说，设计一个符号的流程包括：

The Symbol Editor main window is shown below. It has three toolbars for quick access to common features and a symbol viewing/editing canvas. Not all commands are available on the toolbars, but all commands are available in the menus.

In addition to the toolbars, there are collapsible panels for the symbol tree and properties manager on the left. The bottom of the window contains a message panel that shows details about the selected object.

The button displays or hides the list of available libraries, which allows you to select an active library. When a new symbol is created, it will be placed in the active library.

Clicking on a symbol name opens that symbol in the editor, and hovering the cursor over the name of a symbol displays a preview of the symbol.

After modification, a symbol can be saved in the current library or a different library. To save the modified symbol in the current library, click the icon.

To save the symbol changes to a new symbol, click File → Save Copy As…​. The symbol can be saved in the current library or a different library, and a new name can be set for the symbol.

To create a new file containing only the current symbol, click File → Export → Symbol…​. This file will be a standard symbol library file which will contain only one symbol.

You can create a new symbol library by clicking File → New Library…​. At this point you must choose whether the new library should be added to the global symbol library table or the project symbol library table. Libraries in the global library table will be available to all projects, while libraries in the project library table will only be available in the current project.

Following selection of the library table, you must choose a name and location for the new library. A new, empty library will be created at the specified location.

To create a new symbol in the current symbol library, click the button. You will be asked for a number of symbol properties.

还有几种图形选项。

这些属性以后也可以在符号属性窗口中修改。

一个新的符号将使用上述属性被创建，并将出现在编辑器中，如下图所示。

The blue cross in the center is the symbol anchor, which specifies the symbol origin i.e. the coordinates (0, 0). The anchor can be repositioned by selecting the button and clicking on the new desired anchor position.

符号属性是在创建符号时设置的，但它们可以在任何时候被修改。要改变符号属性，请点击 图标，显示符号属性对话框。你也在编辑画布中空白位置双击打开属性对话框。

设置 单元数量，并检查 所有单元都可互换 和 具有交替的主体风格（如适用）是很重要的，因为这些设置会影响引脚和图形被添加到每个符号单元的方式。

如果你在向符号添加引脚后再改变符号的单元数，你将需要做额外的工作来为额外的单元添加引脚和图形。如果最初正确设置了这些属性，引脚和图形就会自动添加到每个单元。尽管如此，还是可以在任何时候修改这些属性。

图形选项 显示引脚编号 和 显示引脚名称 用来定义引脚编号和引脚名称文本的可见性。选项 将引脚名称置于内部 定义了引脚名称相对于引脚主体的位置。如果该选项被选中，引脚名称将被显示在符号的轮廓内。在这种情况下，引脚名称位置偏移 属性定义了文字远离引脚末端的位置。通常，0.02 到 0.05 英寸是合理的。

下面的例子显示了一个没有勾选 将引脚名称置于内部 选项的符号。注意名称和引脚编号的位置。

Symbols contain multiple fields, which are named values containing information related to the symbol. Fields can be displayed on the schematic or hidden and only shown in the symbol’s properties. Some fields have special meaning to KiCad: Reference and Footprint are both critical for creating a PCB, for example. Other fields may contain information that is important for a design but is not interpreted by KiCad, like pricing or stock information for a part.

Any fields defined in a library symbol will be included in the symbol when it is added to a schematic. You can also add new fields to symbols in the schematic. Whether they are in the library symbol or not, these fields can then be edited on a per-symbol basis in the schematic. They are also transferred to the symbol’s corresponding footprint in the PCB.

All library symbols are defined with five default fields: Reference, Value, Footprint, Datasheet, and Description, which are added whenever a symbol is created. These default fields cannot be deleted. Only the Reference field is required to have a value: the contents of a library symbol’s Reference field is used as the reference designator prefix when the symbol is added to a schematic. In the schematic, the symbol’s Reference field contains the entire reference designator.

如果使用 封装 字段，则包含符号与封装关联。格式是 LIBNAME:FOOTPRINTNAME，其中 LIBNAME 是封装库表中的封装库名称（见 PCB 编辑器手册中的 封装库表部分），FOOTPRINTNAME 是 LIBNAME 库中的封装名称。

The Description field can contain text describing the symbol such as the component function, distinguishing features, and package options. Together with the symbol’s name and keywords, text in this field is used when searching for symbols in the Symbol Chooser or Symbol Editor. Before KiCad version 8.0, this was a dedicated property (like the symbol name and keywords) rather than a symbol field.

Symbols defined in libraries are typically defined with only these five default fields. Additional fields such as vendor, part number, unit cost, etc. can be added to library symbols but generally this is done in the schematic editor so the additional fields can be added to every symbol in the schematic, not just all symbols of one type.

要编辑一个现有的符号字段，请双击该字段，选择它或悬停并按 E，或右击字段文本并选择 属性…​。

To add new fields, delete optional fields, or edit existing fields, use the icon on the main tool bar to open the Symbol Properties dialog. Fields can be arbitrarily named, but names starting with ki_, e.g. ki_description, are reserved by KiCad and should not be used for user fields.

Fields have a number of properties, each of which is shown as a column in the properties grid. Not all columns are shown by default; columns can be shown or hidden by right clicking on the grid header and selecting or deselecting columns from the menu.

封装筛选器标签用于定义哪些封装适合与符号一起使用。筛选器可以在封装分配工具中使用，以便只显示每个符号合适的封装。

可以定义多个封装筛选器。符合任何一个筛选器的封装将被显示；如果没有定义筛选器，那么所有的封装都将被显示。

筛选器可以使用通配符。* 匹配任何数量的字符，包括零，而 ? 匹配零或一个字符。例如，SOIC-* 将匹配 SOIC-8_3.9x4.9mm_P1.27mm 封装以及任何其他以 SOIC- 开头的封装。筛选器 SOT?23 匹配 SOT23 以及 SOT-23。

Symbols can have more than one unit per package, each with different graphics and pin configurations. This is often used for logic gates, opamps, or other components that have multiple subunits within one physical package. Symbols can also have up to two body styles, a standard symbol and an alternate symbol often referred to as a "De Morgan equivalent".

For example, consider a relay with two switches, which can be designed as a symbol with one body style and three different units: a coil, switch 1, and switch 2. Designing a symbol with multiple units per package and/or alternate body styles is very flexible. A pin or a body symbol item can be common to all units or specific to a given unit or they can be common to both symbolic representation so are specific to a given symbol representation.

By default, pins are specific to a unit and body style. When a pin is common to all units or all body styles, it only needs to be created once, no mattery how many units or body styles are used. This is also the case for the body style graphic shapes and text, which may be common to each unit, but typically are specific to each body style.

要向一个符号添加额外的单元，在符号属性对话框中将 单元数量 属性设置为适当的数字。默认情况下，符号单元被命名为 单元 A、单元 B 等，但你可以使用 编辑 → 设置单元显示名称…​ 为当前单元设置一个任意的名称。

Use the unit selection dropdown to select the unit you wish to edit.

要添加一个备用的主体样式，请在符号属性对话框中设置 存在备用的主体样式（德摩根） 属性。

If the symbol has an alternate body style defined, one body style must be selected for editing at a time. To edit the normal representation, click the icon. To edit the alternate representation, click on the icon.

Graphical elements create the visual representation of a symbol and contain no electrical connection information. You can draw new graphic shapes using the buttons on the right toolbar. The following types of objects are available:

Each graphic item (line, arc, circle, etc.) can be defined as common to all units and/or body styles or specific to a given unit and/or body style.

Element options can be quickly accessed by right-clicking on the element to display the context menu for the selected element. You can also double-left-click on an element to modify its properties, or edit its properties using the properties manager pane.

Below is the properties dialog for a polygon element.

图形元素的属性是：

可以点击 按钮来创建和插入一个引脚。可以通过双击引脚来编辑引脚的属性。也可以删除或移动你已经添加的引脚。必须小心地创建引脚，因为任何错误都会对 PCB 设计产生影响。

一个引脚是由它的图形表示、名称和编号定义的。引脚的名称和编号可以包含字母、数字和符号，但不能包含空格。 为了使电气规则检查（ERC）工具发挥作用，引脚的电气类型（输入、输出、三态…​）也必须被正确定义。如果这个类型定义不正确，原理图上的 ERC 检查结果可能是无效的。

要点：

Power symbols are symbols that are used to label a wire as part of a global power net, like VCC or GND. The power symbol’s Value field determines the net label. The behavior of power symbols is described in the electrical connections section. Power symbols are handled and created the same way as normal symbols, but there are several additional considerations described below.

将电源符号放在一个专门的库中可能是有用的。KiCad 的符号库将电源符号放在 power 库中，用户可以创建库来存储自己的电源符号。如果在符号的属性中勾选了 定义为电源符号 框，该符号就会出现在原理图编辑器的 添加电源符号 对话框中，以便于访问。

Power symbols consist of a single pin of type Power Input. They must also have the Define as power symbol property checked.

下面是一个 GND 电源符号的例子。

要创建一个电源符号，请使用以下步骤：

An easier method to create a new power symbol is to use another symbol as a starting point.

符号编辑器可以检查符号中的常见问题。使用顶部工具栏上的 按钮运行符号检查器。

符号检查器检查的是：

电阻、电感和电容的模型是可以推断，这意味着 KiCad 将检测到它们是无源的并自动分配适当的仿真模型。 因此它们不需要任何特殊设置； 用户只需要设置符号的 值 字段即可。

KiCad 根据以下标准推断符号的仿真模型：

Inferred models are ideal models. If the simulation requires a non-ideal model, for example an inductor with parasitic capacitance included, you must explicitly assign a model that includes it.

KiCad 提供多种标准仿真模型。 它们不需要外部模型文件。 以下元件可用：

要将内置模型添加到符号，请打开仿真模型编辑器对话框（符号属性 → 仿真模型…​）并选择内置 SPICE 模型。

有关这些模型的更多详细信息，请参阅 ngspice 文档。

元件 设置要仿真的元件类型：电阻、BJT、电压源等。此值存储在符号的 Sim.Device 字段中。

类型 选择用于元件的模型类型。 大多数元件都有多种类型的模型可供选择，它们的准确度、优化的特性以及可用参数可能会有所不同。 有关详细信息，请参阅 ngspice 文档。 该值存储在符号的 Sim.Type 字段中。

参数 选项卡显示元件的参数并允许您编辑它们。 例如，电阻器的电阻、电压源的波形、MOSFET 的宽度和长度等。任何与模型默认值不同的参数都存储在符号的 Sim.Params 字段中。

编码 选项卡显示生成的 SPICE 模型，因为它将被写入 SPICE 网表以进行仿真。

在值字段中的保存参数 '<parameter name>' 复选框使用符号的 值 字段而不是 Sim.Params 字段来存储参数。 这可以更轻松地从原理图编辑简单模型，而无需打开仿真模型编辑器。 此选项仅适用于理想的无源模型（R、L、C）和直流电源。 如果符号中存在 Sim.Params 字段，它将优先于 值 字段。

KiCad can also load SPICE models from external files, and this is typically how you will add a SPICE model of a specific commercially-available part (say, a 555 timer, or a TL071 operational amplifier, for example) to your simulation. These models must be in a standard SPICE format and must not be encrypted. Models such as these are readily available from numerous sources - manufacturer’s web-sites being just one example.

要从外部文件加载模型，请打开仿真模型编辑器对话框（符号属性 → 仿真模型…​）并从文件中选择 SPICE 模型。

File is the path to the model file to use. Unencrypted model files are plain, human-readable text files and often have extensions such as .lib, .sub etc., although KiCad will accept a valid model with any extension.

The path to the file can be absolute, or relative to the project folder. The path can also be relative to the value of SPICE_LIB_DIR if you have defined that path variable. The library filename is saved in the symbol’s Sim.Library field.

Model is the name of the desired model in the model file. A model file may contain multiple models, and if so they will all be listed in the dropdown. The selected model is listed in the symbol’s Sim.Name field.

可以使用 parameters 选项卡覆盖参数（或指定其他参数）。 在所选模型或 参数 选项卡中指定的所有参数都存储在符号的 Sim.Params 字段中。

编码 选项卡显示生成的 SPICE 模型，因为它将被写入 SPICE 网表以进行仿真。

IBIS（I/O 缓冲区信息规范）文件是 SPICE 模型的替代品，用于对数字部件上的输入/输出缓冲区的行为进行建模。 为了加载 IBIS 文件，用户应遵循 SPICE 库模型的相关流程，并提供一个 .ibs 文件。

文件 是要使用的模型文件的路径。 路径可以是绝对路径，也可以是相对于项目文件夹的路径。 路径也可以是相对于 SPICE_LIB_DIR 的值，如果你已经 定义该路径变量。 库文件名保存在符号的`Sim.Library`字段中。 如果加载了 IBIS 模型文件，对话框中的其余字段将与 IBIS 模型相关。

元件 从 IBIS 文件中选择要使用的元件，因为 IBIS 文件可以包含多个元件。 元件名称保存在符号的 Sim.Name 字段。

Pin 选择 IBIS 模型中的哪个引脚进行仿真。 所选引脚必须映射到 引脚分配 选项卡中的符号引脚。 所选引脚的编号保存在符号的 Sim.Ibis.Pin 字段中。

模型 是所选引脚可用的模型列表，例如输入或输出。 所选模型名称保存在符号的 Sim.Ibis.Model 字段中。

类型 选择引脚在仿真中应该做什么。 引脚可以是不驱动任何值的无源元件； 它可以是驱动高阻抗、低阻抗或高阻抗的 DC 驱动器； 或者它可以是 矩形波 或 PRBS 驱动器。 该值存储在符号的 Sim.Type 字段中。

参数 选项卡可让您查看和编辑模型的参数。 对于每个参数，您可以在 IBIS 文件中定义的最小值、典型值或最大值之间切换。 您还可以根据引脚选择的类型来选择驱动波形的参数。 任何不同于默认值的参数都存储在符号的 Sim.Params 字段中。

Simulation models may have their pins numbered differently than the corresponding symbol. For example, SPICE models for diodes usually consider pin 1 to be the anode, while schematic symbols are usually drawn with pin 1 as the cathode. Operational amplifier models are also very likely to have model pin assignments that do not match package or schematic pin numbers.

您可以使用仿真模型编辑器的 引脚分配 选项卡将符号的引脚映射到仿真模型引脚。

The left column displays the name and number of each symbol pin, i.e. the pin numbers and names that appear on the schematic part in KiCad. The right column displays the corresponding pin as defined in the model file in use. For each symbol pin, you can select the corresponding pin from the simulation model in the dropdown in the right column. In the cases where a schematic part has pins that are not in the model, as in the case of an operational amplifier with 'nulling' pins that are not modeled, the schematic part pin may be assigned to the 'Not Connected' option in the Pin Assignments dropdown. Unlike other pin assignments, 'Not Connected' may be assigned to multiple pins if necessary.

When you use a subcircuit model, the dialog displays the model’s code under the pin assignments for use as a reference while assigning pins. A well-written model will often include a helpful reference section (as a set of comments) to inform the user how the model pins are mapped.

要运行仿真，请在原理图编辑器窗口中单击 检查 → 仿真 或使用顶部工具栏中的 按钮打开 SPICE 仿真器对话框。

该对话框分为几个部分：

Workbooks are files that store information about the simulation environment, including simulation setup parameters and the list of signals available for use. They can be used to store the setup for a set of analyses, which can then be reloaded and rerun at a later time. A workbook can include more than one simulation - for example, it may contain separate tabs for Transient (TRAN), Operating Point (OP), and Small Signal AC (AC) analyses which you added as you worked.

You can save a workbook using File → Save Workbook and load one using File → Open Workbook.

Before running a simulation, you need to select a simulation type and set the simulation parameters. This can be done using Simulation → Settings…​ or the Sim Command button () and then selecting one of the available analysis types:

These analysis types are explained in detail in the ngspice documentation.

Another way to configure a simulation is to type SPICE directives into text fields on schematics. Any text field directives related to a simulation command are overridden by the settings selected in the dialog. This means that once a simulation has run, the dialog overrides the schematic directives until the simulator is reopened.

Once the simulation command is set, a simulation can be started with Simulation → Start Simulation (Ctrl+R) or the Run/Stop Simulation button ().

It is possible to change the value of passive (R, L, C) simulation elements using sliders in order to graphically adjust them. Whenever the slider is set to a new position, the simulation is run with the new parameters and the current simulation plot is updated. In order to add a slider for a component, use Simulation → Add Tuned Value…​, the keyboard shortcut T or the button in the toolbar, and then click on the component to tune.

In addition, it is possible to restrict the component values to those from a particular series of Preferred Values — either of the E24, E48, E96 or E192 series. This is particularly useful when it is necessary to restrict component values to commercially available parts.

KiCad 的仿真器提供了两种导出结果的方式：

Only simulations that produce plots (see above) can be exported as an image or a CSV file. The results of OP and PZ analyses cannot be exported in this way.

Sometimes a simulation will fail, either with or without errors being reported. Paying attention to the error messages reported, taking care in the development and entry into KiCad of the circuit to be simulated, and making use of the KiCad, ngspice and general SPICE documentation and information from fellow users in forums is very worthwhile and can often point the way to a solution.

It’s worth noting, for users unfamiliar with SPICE, ngspice or circuit simulation in general that some 'common' and interesting circuits can sometimes be tricky to simulate accurately or reliably. These include apparently simple circuits such as oscillators, which in some cases may fail to oscillate at all! It is nearly always possible to build a working simulation but sometimes this can more require SPICE experience than might be initially apparent, or the guidance of someone who already has it. The ngspice documentation, once again, is worth reading for insights into good and effective simulation practices if you are encountering difficulty.

Fundamentally the KiCad Simulator is a user-friendly front-end to the powerful ngspice circuit simulator. Therefore problems with the details of simulation, the correct use of SPICE elements, models, etc. is beyond the scope of the KiCad documentation but is very likely to be fully and completely addressed in the ngspice documentation itself. It’s therefore recommended not to overlook this valuable resource.

Although it is certainly possible to keep simulation models (i.e. .lib, .sub files) in the directories associated with individual KiCad projects, this will likely result in unnecessary copies of model files proliferating as you create simulations. Consider creating a dedicated storage location (directory, folder) for models, perhaps organized by manufacturer or device type, to hold these files. Then they may simply be referenced in simulations at a common location.

要创建一个数据库关联库，你必须创建一个配置文件，其中包含 KiCad 连接到你的数据库的必要信息并从表中获取数据。 将下面的模板复制到一个新文件中，并以 kicad_dbl 为扩展名保存。 然后你可以使用配置符号库对话框将此文件添加到你的全局符号库表中。

创建配置文件并将其添加到符号库表中后，您可以使用符号选择器从数据库表中放置元件。 从数据库关联库中放置的元件可以使用 "从库中更新符号" 功能进行更新，该功能将更新数据库中被改变的任何字段，以及更新源库中被改变的符号。

请注意，数据库表所引用的任何源库也必须存在于符号库表中，这样数据库关联库库才能正常工作。 如果你想把一个库只作为数据库关联库的符号源，你可以通过清除 "管理符号库" 对话框中的 "可见" 复选框将其从符号选择器中隐藏起来。

To create an HTTP library, you must create a configuration file that contains the necessary information for KiCad to connect to the providing library (API) and to retrieve data from it.

Copy the template below into a new file and save it using the .kicad_httplib file extension. You should then edit this file and replace root_url and token values with your own. Once saved, add this file to your global symbol library table using the Configure Symbol Libraries dialog which can be found under Preferences→Manage Symbol Libraries…​.

Users have the option to configure two timeout settings. The timeout_parts_seconds setting dictates the validity duration of a part’s information, while the timeout_categories_seconds setting determines how long categories remain valid. The default values are set to 60 seconds and 600 seconds respectively, but if the data for either setting is anticipated to remain unchanged, users can opt for higher values. This will significantly speed up the opening of the symbol chooser. It’s important to note that KiCad will re-cache the data on the initial startup regardless of these timeout settings.

Authentication is done via an Access Token only. Users need to ask their administrators to get a valid token issued if the HTTP library is maintained externally.

KiCad caches all available Categories once when opening the Symbol Chooser Dialog. Subsequently, any alterations made to the categories on the server side will remain undetected by KiCad until the user performs a program restart. This implementation is intentionally designed to conserve bandwidth resources, as it prevents KiCad from attempting to retrieve data from the API every time the user opens the Symbol Chooser Dialog. Such continuous data fetching, especially under constrained bandwidth conditions, would severely impede KiCad’s performance.

If KiCad receives an API error, it will display an error message to the user. For more information about API errors and server responses, see the APIs and Bindings section at dev-docs.kicad.org.

新的网表生成器可以通过点击 添加生成器…​ 按钮添加到 导出网表 对话框中。

新的生成器需要一个名称和一个命令。名称显示在标签中，只要点击 导出网表 按钮，就会运行该命令。

当网表生成时，KiCad 会创建一个中间的 XML 文件，其中包含原理图中所有的网表信息。然后运行生成器命令，以将中间网表转换为所需的网表格式。

网表命令必须正确设置，以便网表生成器脚本将中间网表文件作为输入并输出所需的网表文件。确切的网表命令将取决于所使用的生成器脚本。下面描述了命令格式。

Python 和 XSLT 是创建自定义网表生成器的常用工具。

KiCad 还使用中间网表文件，通过 BOM生成工具生成 BOM。

通过点击 按钮，可以在 BOM 生成器脚本列表中添加其他脚本。点击 按钮，可以删除脚本。 按钮在文本编辑器中打开所选的脚本。

用 Python 和 XSLT 编写的生成器脚本可以包含一个标题注释，描述生成器的功能和用法。这个标题注释会作为每个生成器的描述显示在 BOM 对话框中。标题注释必须包含字符串 @package。该字符串之后直到注释结束的所有内容都被用作生成器的描述。

当添加新的生成器脚本时，KiCad 会自动填充命令行字段，但根据生成器脚本的情况，可能需要手工调整命令行。KiCad 试图从生成器脚本标题中的示例命令行自动确定输出文件扩展名。

网表或 BOM 导出器的命令行定义了 KiCad 将运行的命令，用以生成所选输出文件。

对于使用 xsltproc 的网表导出器，以下为一个示例：

xsltproc -o %O.net /usr/share/kicad/plugins/netlist_form_pads-pcb.asc.xsl %I

对于使用 Python 的 BOM 导出器，以下为一个示例：

/usr/bin/python3 /usr/share/kicad/plugins/bom_csv_grouped_by_value.py "%I" "%O.csv"

某些字符序列（如 %I 和 %O）在命令行中具有特殊含义，因为 KiCad 在执行命令之前将它们替换为文件名或路径。

当输出 BOM 文件和网表时，KiCad 会创建一个中间网表文件，然后运行一个单独的工具，将中间网表后期处理成所需的网表或 BOM 格式。

中间网表使用 XML 语法。它包含有关设计的大量数据。根据输出（BOM 或网表），完整中间网表文件的不同子集将包含在最终输出文件中。

中间网表文件的结构详述 如下。

由于从中间网表文件到输出网表或 BOM 的转换是文本到文本的转换，因此可以使用 Python、XSLT 或任何其他能够将 XML 作为输入的工具编写后处理过滤器。

此示例提供了网表文件格式的概览。