General Settings:
Debug Grid - Shows the grid before it turns into a circuit to clearly see what mesh structure the user is working with
Use Original Mesh - If pressed, it will use the mesh of this object, and if not, it creates a flat Grid that can be configured
Show Original Geometry - Shows the original mesh if needed
Quad/Hex - Defines the structure of Grid. If the Use Original Mesh option is selected, it leaves the structure untouched in Quad mode and tries to turn it into hexagons in Hex mode
Alt Triangulate - Divides the mesh diagonally. This is necessary to give greater variability to the structure of the Grid and, accordingly,
for Circuit. Here's an example: 

Use Vertex Group - When clicked, it allows you to use only the desired areas of the mesh using Vertex Group
Vertex Group - Specify the desired vertex group by clicking on the square
Material - Allows you to select the material for the entire Circuit. By default, the kit comes with white glowing material for demonstration. You can change it or replace it with your own
Grid Settings: This functions works only if "Use Original Mesh" is turned off
Size X - Grid size along X-axis
Size Y - Grid size along Y-axis
Vertices X - Number of vertices along the X axis
Vertices Y - Number of vertices along the Y axis
Hex Grid Density - Defines the mesh resolution in Hex mode
Circuit Settings:
One/Multiple Ends - Allows you to determine how the pattern of Circuit will spread. If the "One end" mode is enabled, then the pattern will come from one vertex, and if the "Multiple end" function is enabled, then there will be more than one such source
End Index - If the "One end" function is enabled, it allows you to select the source of the entire pattern by vertex index
Start Probability - Allows you to select the probability with which the vertex will be the Start of the pattern
End Probability - Allows you to select the probability with which the vertex will be the End of the pattern
End Seed - Allows you to change the distribution of Ends to another if the current one does not suit you
Start Seed - Allows you to change the distribution of Starts to another if the current one does not suit you
Profile Settings:
Flat - Makes Circuit flat. Needed if you need a flat Circuit or for optimization
Profile Vertices - determines the number of vertices in the profile. You can increase it if you need high detail, or lower it if the Circuit is far from the camera for optimization purposes. Or for styling
Radius - Profile radius
Circle Resolution - determines the number of vertices in the circles at the ends of Circuit. You can increase it if you need high detail, or lower it if the Circuit is far from the camera for optimization purposes. Or for styling
Circle Radius - Radius of circles at the ends of Circuit
Noise Settings: Here are the settings for Noise texture, which regulates the curvature and tortuosity of the pattern. This is in case you need to change it for some reason
Scale
Detail
Roughness
Lacunarity
Distortion
Subdivision for Visualization: - In some cases (especially if the "Alt Triangulate" function is enabled or the mesh has few polygons), the Circuit may not fully correspond to the original mesh. This function will allow you to subdivide the mesh so that it matches the Circuit shape
Subdivide - Turning on Subdivision
Subdivision Level
Advanced:
Rotate Circle - Allows you to rotate the circles at the ends of the Circuit in case you want to stylize using for example circles with a resolution of 4 or 6
Rotate Profile - Allows you to rotate Profile of the Circuit in case you want to stylize using for example Profile with a resolution of 4 or 6
Custom Offset - Allowing you to manually adjust the indentation of the ends of Circuits from Circles in case the automatic indentation does not suit you or does not work due to styling
Offset - new offset value
Use Custom End - Allows you to manually select which vertices the pattern of Circuit will be reduced to using vertex groups
End Vertex Group - Specify the desired vertex group by clicking on the square
Use Alternative Grid - Allows you to select other pattern options for Circuit
Variant - select option from 1 to 9
Experimental:
Uniform Mesh Density - This function allows you to make the mesh density of the original mesh uniform. This is necessary in cases where it is not uniform and because of this, parts of the Circuit overlap. This function is based on a combination of Mesh to Volume and Volume to Mesh, and the settings below apply to these nodes
Density - 
Voxel Size - 

DevLog

I made a small update that adds the ability to control which point will be the local center of the circuit. These can be any objects in the collection you select. And you can move them if you want to make an animation and the circuit will update according to how you move the objects in the collection. This function is only available in the file "(New , 4.0+ only) Procedural Circuit + Collection Proximity". Unfortunately, this function is only available in Blender versions starting from 4.0 because it uses repeat zone to highlight each object from the collection as a selection. In version 3.6, this function could use only one object to indicate the center - and accordingly there would be only one center. That is why I did not create a separate update for 3.6, but if any of you for some reason need such an option, then I can make a version for 3.6, just write to me.




How to append this assembly to your (already excisting) project: 
To add an assembly to your project, you need to click on the "File" button on the upper left corner of Blender, then "Append",
then find the "Procedural Circuit.blend" on your PC and click on it, then in the "NodeTree" folder select node group "Procedural Circuit". 
Then select the desired object , add the "geometry nodes" modifier and select "Procedural Circuit".