Electronic – CAN network resistor termination


My question is about the resistor for termination in a CAN network.
From an electrical perspective why should we add this resistor (commonly 120 Ohm) between the CAN_H and CAN_L?
Thanks in advance.

Best Answer

Because the end of transission line has to be terminated with characteristics impedance of transmission line itself. If the line is not terminated, when the signal travels to the end, it bounces back (reflection) and creates standing wave, similarly like sea wave bounces back when it hits the shore.
Any termination that does not match the characteristics impedance is causing reflections, the worst case is short circuit or open circuit.

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