Friday 5new - Name:_ Impedance Matching Friday 5 We have...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Name:___________________________ Impedance Matching Friday 5 We have been saying that if the impedance is matched between two media, then there will be no reflection of waves as energy passes from one medium to another. If a wave pulse passes from medium number 1 with impedance Z 1 and strikes a medium number 2 that has impedance Z 2 , the ratio of the amplitude of a reflected wave pulse A r to the incident wave pulse A i is given by: 21 1/ r i AZ Z Z = + Plot of the ratio A r / A i given the ratio Z 2 /Z 1 Fig. 1 Notice that if a wave reflects from a low impedance ( Z 2 less than Z 1 ) then the reflected pulse has the same sign and nearly the same amplitude as the incident pulse. If it reflects from a high impedance ( Z 2 greater than Z 1 ) then the sign is inverted. This is what we saw with reflections on the wave machine in lecture. If the impedance ratio is 1, this means that the impedances are the same and then the amplitude of the reflected wave is zero. This is called "impedance matching".
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

Friday 5new - Name:_ Impedance Matching Friday 5 We have...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online