[XCSSA] Blowing Fuses and Unsure Why

[X-otic Computer Systems of San Antonio]

Tim,

The light bulb in series acts as a resistor and thus limiting the current. 
 As the wire in the bulb gets hotter, the resistance goes up. The switch 
would also be in series to the bulb on the AC side, it would just give you 
and easy flow interruption. 

Tweeks,

FLAME Jacket on!

150W???? wouldn't that be like 1+A on the AC side 120V... he is trying to 
protect .5 or even 1A on the 9v side.  If my memory serves me right 
(please correct where necessary), 9Vx1A = 9Watts and 9Watts/120V = 0.075A. 
 This would indicate that we do not want to draw more than .10A from the 
120V side, right?  Those calcs do not take into account the 5v section.  A 
larger bulb allows larger currents before lighting, so wouldn't he want a 
smaller bulb? maybe in the 10-15W range?  This IS a new trick for my 
books!  Please elaborate.

Flame OFF!

PS... My Mega tree died at the hands of some teenagers and a car... ; - ( 
PS II. I still intend on giving a show and tell on my light controllers 
and the software at the next XCSSA meeting (January 19th?).  I will also 
bring my new 6432 LED matrix controller board... Grin...


Thanks,


Charles S. 


From:
X-otic Computer Systems of San Antonio <xcssa at xcssa.org>
To:
xcssa at xcssa.org
Date:
01/09/2009 11:25 AM
Subject:
Re: [XCSSA] Blowing Fuses and Unsure Why
Sent by:
xcssa-bounces at xcssa.org



Hi Tweeks!

I think I get what you're saying, but that's for if the fuse on the 
left of my xformer blows right? Can I use this setup if one of my 
fuses blows to the right of the xformer? The only fuse that's blowing 
is on the 9V rail - the 5V works just fine before and after the fuse 
blows on the other side.

Now, if I understand you correctly, I can hook this up so that the 
bulb lights up iff there is a short? I'm a little fuzzy on that so I 
don't suppose you have a picture? I actually have extra light bulbs, 
so this might work out well!


On Jan 9, 2009, at 11:19 AM, X-otic Computer Systems of San Antonio 
wrote:

> On Wednesday 07 January 2009, X-otic Computer Systems of San Antonio 
> wrote:
> [...]
>> Unfortunately, I ran out of pico fuses. Whoops :) Guess I should use
>> those in a final design since they are sort of a pain in the ass to
>> replace, doh!
>
> Hey Tim..
>
> A Little electronic bench t-shooting tip from my pro-audio tech days:
> When you have a prototype circuit (or just something you have on the 
> bench)
> that keeps blowing fuses.. Instead of continually replacing them or 
> doing
> pico fuses.. (or foolishly hard wire bypassing the fuse <ug>)... 
> Instead,
> just wire a 150-300 watt light bulb sock in series with your AC 
> cable and
> screw the bulb socket down to the bench (maybe throw a 15A light 
> switch in
> line with that too):
>                http://images.hardwareandtools.com/P/u251470.jpg
>                http://www.cacheboxstore.com/images/Large/Light
> Bulb/lightbulbfixturelarge.gif
>                
http://images.marketworks.com/hi/58/57750/EA293V-BOX-10pk-2.jpg
>
> That way you can draw up to an amp or so just fine.. but over that.. 
> you just
> light the light bulb instead of blowing a fuse.  What this also does 
> is it
> gives you time to track down the short (while the bulb is lit). 
> Whatever
> component (or wire) is shorted, it will end up getting rather toasty
> (usually) and emit a "distinctive smell" which you can then either 
> track down
> by smell or by touch (ouch!). :)
>
> Hope that helps..
>
> Tweeks
>
>
>
>
>> Oh well. I'll order some more of those once I know
>> what's going wrong.
>>
>> Thanks, as always, for the help!
>>
>> Tim
>> _______________________________________________
>> XCSSA mailing list
>> XCSSA at xcssa.org
>> http://xcssa.org/mailman/listinfo/xcssa
>
>
>
>
> Confidentiality Notice: This e-mail message (including any attached or
> embedded documents) is intended for the exclusive and confidential 
> use of the
> individual or entity to which this message is addressed, and unless 
> otherwise
> expressly indicated, is confidential and privileged information of 
> Rackspace.
> Any dissemination, distribution or copying of the enclosed material 
> is prohibited.
> If you receive this transmission in error, please notify us 
> immediately by e-mail
> at abuse at rackspace.com, and delete the original message.
> Your cooperation is appreciated.
>
> _______________________________________________
> XCSSA mailing list
> XCSSA at xcssa.org
> http://xcssa.org/mailman/listinfo/xcssa
>

_______________________________________________
XCSSA mailing list
XCSSA at xcssa.org
http://xcssa.org/mailman/listinfo/xcssa


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://xcssa.org/pipermail/xcssa/attachments/20090109/d445eef9/attachment.html