Adding wire/Lengthening wires...

Detman101

Limp Gawd
Joined
Nov 22, 2005
Messages
153
I have been working on a power cable for my Pinhole camera. When I modified a Molex adapter to power the thing by adding a length of wire to the negative and positive leads the thing just doesn't work. I don't know why? I kept the connections clean and soldered them. I shrink wrapped the areas where I soldered the wires and there are no shorts in the cable.
But for some reason the thing just doesn't work.

So I took it apart and used different new wire from Radioshack and I get the same results.
Apparently the person below had the same problem with their CCFLs when they added wire.

Astral Abyss said:
Hmmm.

I was asking because I had to lengthen the wires on one of my 12" cathode tubes in order to get it to reach the inverter. The cathode exhibits a strange behavior now. The wires on the cathode are somehow causing interference or resistance with each other. What I mean is when I hold the wires together, the tube won't light up all the way, but when I seperate the wires, the tube lights up fine. There wires are isolated properly, I soldered the extra wire length on and heat shrunk the connections I made. Wasn't something I had expected to happen from adding a short length of wire. I know it's not the solder joint because I shortened the other tubes wiring the same way, by cutting and soldering, and it works fine. I've tried this lengthing on 2 different cathode tubes and they both do the same thing.

Anyhow, that's why I was wondering if you had made any mods to it. I'm kinda hoping mine doesn't melt on me.

It's a Coolermaster Aurora setup.

Is there some sort of resistance or impedance or something that is added into the fray when you add lengths of wire to something for power?

I just can't figure out what the difference is... :confused:
 
Unless you're adding a foot or so of wire, it should be alright... I've lengthened PCIe power cables, ATX 24pin cables, and molex's without soldering them. Just twist the ends together and apply a nice layer of electrical tape, then heatshrink them. It's always worked for me.

Try removing the lengthening process you did for the camera, and see if it works...
 
Arcygenical said:
Unless you're adding a foot or so of wire, it should be alright... I've lengthened PCIe power cables, ATX 24pin cables, and molex's without soldering them. Just twist the ends together and apply a nice layer of electrical tape, then heatshrink them. It's always worked for me.

Try removing the lengthening process you did for the camera, and see if it works...

:eek:
Oh crap!!! That's just what I did. I added like 2 feet of wire. :p
I'll take it apart and make it 7 inches long like the first time when it worked.

DOH!
 
Longer wire means more resistance...

Did you happen to check the voltages after you added the 2' of wire to it?
 
MasterOfTheHat said:
Longer wire means more resistance...

Did you happen to check the voltages after you added the 2' of wire to it?

No I didn't think to try checking it with a multimeter.
:(
I figured it was like with wiring my car.
When I did the system in my car, no matter how long the wire was it carried the same amount of power from the front of the car all the way to the trunk.
 
Its a resistance problem not a impedance problem. resistance is DC and impedance is AC. solder the connections. another solution is to step down the wire gauge to reduce resistance over the distance. alright.. that should be it.
 
And of course, step down = larger guage (just incase you were unclear).

The ohmage of even 100 feet of 20guage wire (pretty standard for a computer case IMO) should be just over 1ohm. 1ft of wire should be .1ohms... Which unfortunatly is enough to dimm a Cathode.


Solution? Easy. Double up your wires (so have 2 strands extending the original wire length) and solder all the connections. That should reduce the resistance significantly. Not enough? Try quadroupling them (it's thick, but it works). Best solution is to buy a cathode extension :). As long as you only use 1 of them, they don't dim the light at all (I JUST got one in today and can back this statement up, at least for UV cathodes).
 
Darkala said:
Its a resistance problem not a impedance problem. resistance is DC and impedance is AC. solder the connections. another solution is to step down the wire gauge to reduce resistance over the distance. alright.. that should be it.

So if the wire I bought is 18 guage I need something like 24 or higher?
 
Detman101 said:
So if the wire I bought is 18 guage I need something like 24 or higher?

No......
Wires get thinner as the gauge number goes higher.
You need to go from 18 gauge to 16 or 14.

A 24 gauge is like the size used for fan wires.

 
rodsfree said:
No......
Wires get thinner as the gauge number goes higher.
You need to go from 18 gauge to 16 or 14.

A 24 gauge is like the size used for fan wires.


That's weird. The smaller number wires I saw had one thick copper wire in the middle.
If I were to keep the wire the same as the Molex wiring I would need something with multiple strands correct? Where can I get some molex wireing? I mean, besides cannibalizing molex extensions like I first did. :p
 
Speaker wire is... Ok at best. Half of the wire is copper and the other half is aluminum... Adds to resistance.
 
Arcygenical said:
Speaker wire is... Ok at best. Half of the wire is copper and the other half is aluminum... Adds to resistance.
Depends on the quality of the wire. Try 14 gauge wire.
 
Like anything, you pay for what you get. I like to avoid speaker wire simply because the good stuff (sold via A/V stores) can cost, well... alot.
 
for a power cable, you'll have to have either really shitty connections or a very, very long power cable to notice anything.
 
that would be .01 ohms, which is pretty much nothing

Arcygenical said:
The ohmage of even 100 feet of 20guage wire (pretty standard for a computer case IMO) should be just over 1ohm. 1ft of wire should be .1ohms... Which unfortunatly is enough to dimm a Cathode.
 
Whatsisname said:
for a power cable, you'll have to have either really shitty connections or a very, very long power cable to notice anything.

Is 3 feet too long?
 
Whatsisname said:
for a DC power cable, 3 feet is a long way away from "too long", you'll be fine.

Well, that narrows it down to either 2 things.

1. 12V is too much for the 9V pinhole camera device (Regardless of what the paperwork says)
2. There is a break somewhere in the wires, either the ground or power line.

I decided to just take a car adapter for a 9V device, deconstruct it, and wire that up to a molex adapter so that my pinhole camera has the correct amount of voltage going to it.
 
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