If you are doing automotive then get one for each. voltage you would like to
have.
I have never seen a motherboard that actually uses the -5 volts for memory,
in fact most asus motherboards dont even connect that pin anymore.
Here's a big note: DO NOT try to use desktop hard-drives in a mobile
environment. regular 3.5 inch hdd's are fragile and suck up power like a
vaccuum cleaner.. use a laptop hdd. and the most you are going to get is
around 30-40 watts of power conversion with limited power filtering an
automotive electrical system ranges from 8 volts to 17 volts with spikes to
48 volts and transient voltage spikes in the thousand volt ranges when heavy
loads switch. a mobile computer power supply is not a simple thing to design
for "long term" use that would give you the 300 watt supply that the desktop
pc power supply will.
as for the jameco number 155723
- 25 Watt
- Input Voltage: 9-18VDC
- Output voltage: 5VDC,
12VDC, -12VDC
- Output current: 4000mA,
250mA, 250mA
- Ripple p-p: 60mV, 80mV, 80mV
- 8-pins
- Size: 2.9"L x 2.7"W x 0.9"H
- Weight: 0.5 lbs.
- Short circuit protection
- Voltage accuracy: +/-2%
- One-year warranty
- Overcurrent protection
- I/O isolation: 100M Ohm min
- ISO-9002 certified company
this will do a 386 or 486slc motherboard.... or anything that is PC-104
do not try to install several of these in parallel... they will fry,smoke an
d burn nicely.
you have to use a diode matrix to keep them from back driving each other
which will drop the 5 volt side below acceptable levels.
this DC - DC converter is really overkill for a wearable though... but it's
dirt cheap at $59.00USD
-----Original Message-----
From: Marcus Porter <
>
To: Timothy Gray <
>
Cc: 
<>
Date: Thursday, July 15, 1999 12:27 PM
Subject: Re: Wearable config (was: RE: Good HMDs)
>>www.jameco.com
>>go to the DC to DC converters...
>>find one that does +12 volts to +5,+12,-12 volts
>>simple as pie
>Do you actually know if such a thing exists or are you just assuming? I
>hope you do because, I would LOVE to find out the part number. I've been
>looking for months such a thing for the pc I keep in my trunk and have
>never found one that didn't cost more than the cost of low power mother
>board (which would get around the power supply with four voltages problem).
>I finally made do with an inverter, which seems kind of a waste.
>
>i.e. Car makes alternating current which is translated into DC which is
>translated back into AC by the inverter which is translated once again into
>DC by the computer's power supply. There has to be a bettter way.
>
>I havn't found a converter in Jameco's catalog that provides all four of
>the needed voltages, but perhaps I've missed it.
>
>>From: Stephens, Brandon <
>
>>To: Brian Rudy <
>;
>><>
>>Date: Wednesday, July 14, 1999 7:50 PM
>>Subject: RE: Wearable config (was: RE: Good HMDs)
>>
>>
>>>What are you using for your power conversion?
>>>
>>> > Current working wearable (WEll it kinda is... it's getting
>>>mothballed soon
>>> > for pc104 setup)
>>> >
>>> > 386 mini-baby AT motherboard...
>>> > ide,svga,sound,network card ... all 2.5 inches tall, with brackets
>>>removed
>>> > (I found there are lots of cards only 2.5 inches tall)
>>> > power converters for 5,12 and -12 volts.
>>>
>>>
>>>
>>>--
>>>Subcription/unsubscription/info requests: send e-mail with subject of
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>>>
>>
>>--
>>Subcription/unsubscription/info requests: send e-mail with subject of
>>"subscribe", "unsubscribe", or "info" to
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>
>Marcus Porter, Webmaster at
>http://www.iisworld.com
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