 EE help, Voltage Drop over copper |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
| bd1308 |
 May 2 2005, 10:08 PM
Post
#1
|
|
Sir Post-a-lot  Group: Members Posts: 8,020 Joined: 24-January 05 From: Louisville,KY Member No.: 3,501  |
okay, i have a question. I'm trying to do Power-Over-Ethernet using the (unused) blue pair of ethernet wires. 5VDC......i run the wire (~70 or so feet) and plug it in, and not enough voltage to boot my wireless router....seems that i need under 1.4VDC....how the hell can i add 5VDC to 1.4VDC. I tried getting one of those adjustable AC adaptors and hooking them in series and parallel... in series neither worked...got like 1VDC, and in parallel, well....i tested it later (after it was working) and found the voltage to be around 14-15VDC.....what the hell?
AC adaptor->modified 10/100->~70 foot run to attic->blue pair seperated from RJ45 Jack->in-to router. |
   |
 
|
  |
Replies
| bondo |
May 2 2005, 11:20 PM
Post
#2
|
|
Practicing my perpendicular parking Group: Members Posts: 4,277 Joined: 19-April 03 From: Los Osos, CA Member No.: 587 Region Association: Central California |
What you need is a power supply with remote sensing.. two wires will power your device.. two other wires will carry no current but measure the voltage at the device. The power supply will use the voltage at the device to regulate its ouput. Thus if you need 9v to get 5v, it will do that. Unfotunately such a supply will cost more, and you'll need 4 wires.
Just do what jkeyzer and lapuwali said. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) |
|
|
|
Posts in this topic
bd1308 EE help May 2 2005, 10:08 PM
914GT First of all, your adapter needs to be able to sup... May 2 2005, 10:19 PM jkeyzer Ohms law will tell you the voltage drop to expect ... May 2 2005, 10:20 PM lapuwali I was just about to type in almost exactly what jk... May 2 2005, 10:30 PM Loser_Cruiser If you truly need a power over CAT 5 cable, it wou... May 2 2005, 10:47 PM bd1308 the AC adaptor is OEM.....5VDC....regulator would ... May 2 2005, 11:33 PM bd1308 ethernet does have 2 unused pairs....cool stuff. h... May 2 2005, 11:36 PM bondo May 2 2005, 11:44 PM bd1308 okay....just thought of something....why couldn... May 2 2005, 11:52 PM lapuwali May 3 2005, 09:09 AM jkeyzer Make sure the 9V adapter is capable of supplying t... May 3 2005, 09:19 AM Dr. Roger won't the EMF surrounding these power wires to... May 3 2005, 09:36 AM jkeyzer Well regulated DC will not have a significant effe... May 3 2005, 10:12 AM davep DC can cause problems also if the current draw is ... May 3 2005, 10:21 AM Tom Perso Couldn't you just double up the wires? Ethern... May 3 2005, 10:29 AM bd1308 jkeyzer: AC power wouldnt work...the bleedthrough ... May 3 2005, 10:42 AM bondo ... May 3 2005, 05:26 PM bd1308 yeah...i'm just not so sure about this whole b... May 3 2005, 06:34 PM 914GT Lynksys makes a power over ethernet adapter kit. I... May 3 2005, 07:45 PM
bondo May 3 2005, 07:51 PM |
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 4th July 2025 - 10:51 AM |
Invision Power Board
v9.1.4 © 2025 IPS, Inc.