i want to make my own cat 5 cable tester. how much voltage can i run through a cat5 cable without breaking it? i want the current to light an LED, but not burn out the cable, those wires are pretty thin

2/10/2007 10:38:42 PM

http://www.powerstream.com/Wire_Size.htm

cat5 is 24 gauge strands... each can carry 0.577amps...

which is actually a significant amount however it also is ~25ohms/1000ft so the drop in the cable is significant...

the average turn on for a standard LED is <10mA...

the math is yours to do...

2/11/2007 12:55:43 AM

just apply an insane frequency

2/11/2007 11:36:40 AM

insane frequency?

2/11/2007 1:08:15 PM

well, 60 hz or so

2/11/2007 3:27:49 PM

christ lord

2/11/2007 10:03:17 PM

we plugged POE into our cat 5 tester so I just pulled it apart to see what we blew up...

inside I found a:

http://www.mouser.com/search/productdetail.aspx?R=CD4017BEvirtualkey59500000virtualkey595-CD4017BE

http://www.mouser.com/search/productdetail.aspx?R=LTA-1000HRvirtualkey57820000virtualkey859-LTA-1000HR X2

http://www.mouser.com/search/productdetail.aspx?R=KA555Ivirtualkey51210000virtualkey512-KA555I

there is a push button to do it automatically and then a single pole single throw switch (the kind that doesn't stick...) that cycles through the LED's...

very simple... connect one LED rail to teh first side of the cable... then connect the other LED segment to the otherside through the cat5 cable...

9V batter, 2 caps and a couple resistors are also on the board... and of course 2 cat5 connectors

2/26/2007 6:25:44 PM

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=DGUS,DGUS:2006-12,DGUS:en&q=build+cat5+tester

2/26/2007 7:56:53 PM

yeah I was also thinking about this on the way home...

for basic continuity you just need 2 cat 5 connectors, 8LED's a 9v battery and a 1k resistor...

to test proper pairing the decade counter works well but you could also do it with and/or gates...

2/26/2007 10:06:36 PM

Just plug that shit into the wall outlet.

2/26/2007 10:55:12 PM

with a 20k 5w resistor that actually wouldn't be a problem...

2/27/2007 11:43:36 AM

I think it was on either engadget or hackaday, but someone built one from a NIC with WOL. they just put 5v through the WOL cable and did a little bit of other shit, and voila - a cable tester.

2/28/2007 1:46:03 PM