characteristics impedence

hi all,

can anybody plz tell how do we measure cahracteristic impedence of a cable, may it be coaxial, stp, utp or power cable.it looks impedence matching and trying to get the maximum power. i s there any other way?

Reply to
mahak
Loading thread data ...

If you really want to do this look here: http://72.14.205.104/search?q=cache:-K9ty8myB2YJ:sist.fnal.gov/archive/2000-topics/Owusu/owusu.doc+measuring+characteristic+impedance+of+cable&hl=en&ct=clnk&cd=8&gl=us

Tom

Reply to
Tom Biasi

Well, you can safely forget about the concept for an equipment power cable.

Graham

Reply to
Eeyore

Just measure it.

1] Measure the "L" with the lead ends short circuited. 2] Measure the open circuit "C" 3] Then Zo= square root of L/C

Some I did last year ...

2mtr of "75ohm" coax L=1.48uH C=146pF ... Zo=100ohm* 2mtr of 50ohm coax L=0.83uH C=168pF ... Zo=70ohm 2mtr of 'twin flex' L=1.23uH C=70pF ... Zo=132ohm 2mtr of 'mains cable' L=2.84uH C=281pF ... Zo=100ohm 3mtr CAT5 patch cable L=2.51uH C=157pF ... Zo=126ohm

(measured twice, still same result!)

Reply to
john jardine

"john jardine"

** Likely the frequency you used for the L and C measurement was not in the normal RF range.

Zo for co-ax tends to rise at low RF and audio frequencies.

....... Phil

Reply to
Phil Allison

I would either look it up in the cable spec, calculate it, or measure it with a TDR.

Good Luck! Rich

Reply to
Rich Grise

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.