How can I use power rails in my schematic?

Adding a power supply symbol is a simple and effective way to add clarity to a schematic design.

DesignSpark PCB provides several of these in the default library "DesignSpark". The symbols available can be seen when using "Add Component" when creating the schematic. Below highlights those available.

 Using each of the above to illustrate a 'clear' schematic layout we cross connect two connectors.

Translating this to a PCB we have all the required connections shown as airwires between the connector pins with the appropriately named nets.

What is special about these symbols?

Examining the Vdd symbol in the component editor reveals it has a net assigned. This feature automatically assigns VDD to any net the symbol is connected to.

How do I create my own symbol for say a +3.3V net?

Possibly the quickest route is to simply edit an existing similar component as shown below. Using the Vdd example we change the Net to +3V3 and save as component name +3V3 in the User library shown by green boxes and arrow. The Library highlighted in orange is your choice, but recommended to be one of your user or custom libraries.
The "Sch Symbol Terminal Name" should be changed from Vdd to avoid confusion and here is also edited to +3V3

If we now wish to add this new +3V3 symbol and net, use the "Add Component" as usual and select the User library where symbol +3V3 is now found.

Place the symbols on the schematic sheet and connect to the required component pin. Here we add the new net to pin 1 of each connector.

Forward the design changes to the PCB and we have the new net shown as an airwire* and the net name in the Nets list in the Interaction Bar. Here net +3V3 is selected.

Note * Airwires also known as a "rats nest" represent the point to point net connections which are required to be routed.

Although these symbols are easy to create, there are other common voltage components available in the built-in libraries in the Schema library if you have this enabled

.

See also:

How do I enable the built-in libraries?