Consider the RL circuit with output taken from . The transfer function is

and frequency response function is

where is a vector representing the difference between two points and in the s-plane. Note that and . Consider at three particular frequencies:

- When , we have and , therefore

- When
,
and
, therefore

- When (the corner frequency),
and
, therefore

When the output is taken from , the transfer function is

and frequency response function is

where is a vector from to the origin, and is the same vector as before. When , and . When , both and , and . The system is a high-pass filter.