Basic via question (really)

[frank_8017]

Hey guys,

I am just starting out in PCB design. I usually don't do PCB stuff, but the regular PCB guy is on vacation. I am reviewing his PCB layers, and without a PCB reference guide, I am at loss concerning the different symbols for the vias.

This is what I have figured out so far:
1. Vias wich are a white circle with a black dot in their center mean that the via is not connected on that layer.
2. Vias wich are a white circle with an X in their center mean that the via is connected on that layer.

However, What are the vias that are just white circles ? Are they special with respect to the vias described in 1 & 2 ?

Also, I would appreciate if u could recommend a PCB online tutorial.

Thank you
Frank

[Tom]

Frank,

The vias with an "X" are plane connection vias.

The vias with a circle and a line to the center are "Test Point" vias.

You can RMB (Right Mouse Button) / Select Traces-Pins then select any via then RMB Query/Modify and in the dialog menu the Plane Thermal or Test Point Box will be checked off.

[frank_8017]

But the vias that are just plain white circles, what kind of vias are they ?

[jmellquist]

A via (or pin) with a white circle around it shows an anti-pad on a split-mixed plane. The color in the center (usually dark but can be anything depending on what color you have selected for the pin or via) is the drill.