Subject: | |
From: | |
Reply To: | |
Date: | Sun, 30 Mar 2008 13:06:00 -0500 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
T Behler writes:
>When installing the power poles, how do you keep your zip-cord wires
>straight by color without sighted assistance, when cutting off certain wire
>lengths from a spool? I know how to do it electrically, but I want to be
>sure that I truly do have red wires for all positive leads, and black wires
>for all negative leads.
If you have a light probe and a strong light source like
a flashlight, you might try reflecting the beam off of each lead
to see which one seems to reflect the most light. Both will
reflect some especially if the insulation is glossy, but the red
lead will reflect more than the black.
This isn't going to be much help with wire that comes in
lots of colors like the 8 leads in CAT5 cable, but if you've got
only 2 or 3, one should be able to make a very educated guess.
White will reflect the most light and other colors that
aren't black will reflect lesser amounts with black reflecting
the least.
Now, after all that, be sure your light probe can see
red if it is there. I built a light probe using a lead sulphide
photo cell which is the resistor in a NE555 oscillator. It is
very sensitive to green and yellow light such as day light and
room lighting, but it isn't worth a darn for red or infrared
light.
If you use a photo transistor in your light probe, it
will be very good for red and infrared, but not so good for
green to violette unless it is specifically made to respond to
all visible light.
Martin McCormick WB5AGZ Stillwater, OK
Systems Engineer
OSU Information Technology Department Network Operations Group
|
|
|