What are the difference between impedance board & Non-impedance board？

 

Not familiar with the term.

 

Not familiar with the term.

OK, so i mean what are the difference between pcb board with impedance & with out impedance.

 

OK, so i mean what are the difference between pcb board with impedance & with out impedance.

If you mean "controlled impedance" those are boards that use stripline or microstrip trace design to control the characteristic impedance of a trace for high speed signals.
This is needed to minimize edge reflections of high speed digital signals, or the SWR of RF signals.

Obviously if you don't do that, then the characteristic impedance of a trace is not controlled, but that's not generally not important for low speed signals.

 

If you mean "controlled impedance" those are boards that use stripline or microstrip trace design to control the characteristic impedance of a trace for high speed signals.
This is needed to minimize edge reflections of high speed digital signals, or the SWR of RF signals.

Obviously if you don't do that, then the characteristic impedance of a trace is not controlled, but that's not generally not important for low speed signals.

OK, so if a board belongs to controlled impedance, I can see some lines on the board right?

 

Usually but the lines (traces really) can be buried between layers.

Stripline

 

OK, so if a board belongs to controlled impedance, I can see some lines on the board right?

Even boards without controlled impedance will likely have visible lines (traces), so the mere presence of lines is not a distinguishing feature.

 

It's unlikely you could determine whether a board has controlled impedance traces just by looking at it.