A good, inexpensive PS I''ve found
Archiver
Posts: 46,084
Why heat the room? At least one table-top switching power supply
(14-watt, 5VDC@900mA, 12VDC@800mA, -5VDC@50mA) can be purchased for
$4.25 from Jameco, current catalog page 50.
Dennis
Original Message
From: Mike Sokol myactv [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ohOK5EcjYD_bi-DjUHoUiAqQQ1CIrOtrgyqwsBI_UQ6IhsGPkZXlALqjrKkp8WCrMYUEPSXpcDgUU_V8ewZEtbpk]mikes@m...[/url
Sent: Tuesday, May 13, 2003 9:05 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: A good, inexpensive PS I've found
Rodent,
Remember your Ohm's law. A 5 ohm resistor will draw 1 amp from a 5 volt
supply. It will also dissipate 5 watts of heat. So a 10-watt, 5-ohm
resistor across the 5-volt output of the supply should do the trick. Be
aware that this WILL heat up a bit, so don't put your finger on it while
it's running, and don't let anything flammable touch it. I'm not sure
what the delta-t will be for that resistor, but it will probably get up
to 100 plus degrees F.
Mike Sokol
www.modernrecording.com
mikes@m...
Original Message
From: "Rodent" <daweasel@s...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, May 13, 2003 11:55 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: A good, inexpensive PS I've found
> Well, that blows me out of the water. I'm lucky if many of my Stamp
projects
> draw a couple hundred ma. The other AVR stuff draws even less.
>
> As far as the PC power supplies, we need to define "old." The really
> old
63
> watt and 100 watt XT / AT supplies did need a load. Not sure about the
later
> non-ATX models though.
>
>
Original Message
>
> > 1 amp load on the 5 Volt line will make most (that I have seen
> > anyway) computer power supplies come up.
>
> > The newer ATX power supplies need a load to let the monitoring
> > cirucit turn on the power supply.
> >
> > older power supplies don't need a load to start.
>
> > > Isn't it true that you always need some load on computer power
> > supplies to
> > > work/regulate.
> > > Seem to me I read something about this in N&V some time back. Also
> > > how
> >
> > > would you regulate/limit the current so not to blow
> > anything or in
> > > my case blind by the light when (not if) I short something out.
> > Just can't
> > > trust us mech types with electricity/
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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> and
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(14-watt, 5VDC@900mA, 12VDC@800mA, -5VDC@50mA) can be purchased for
$4.25 from Jameco, current catalog page 50.
Dennis
Original Message
From: Mike Sokol myactv [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ohOK5EcjYD_bi-DjUHoUiAqQQ1CIrOtrgyqwsBI_UQ6IhsGPkZXlALqjrKkp8WCrMYUEPSXpcDgUU_V8ewZEtbpk]mikes@m...[/url
Sent: Tuesday, May 13, 2003 9:05 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: A good, inexpensive PS I've found
Rodent,
Remember your Ohm's law. A 5 ohm resistor will draw 1 amp from a 5 volt
supply. It will also dissipate 5 watts of heat. So a 10-watt, 5-ohm
resistor across the 5-volt output of the supply should do the trick. Be
aware that this WILL heat up a bit, so don't put your finger on it while
it's running, and don't let anything flammable touch it. I'm not sure
what the delta-t will be for that resistor, but it will probably get up
to 100 plus degrees F.
Mike Sokol
www.modernrecording.com
mikes@m...
Original Message
From: "Rodent" <daweasel@s...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, May 13, 2003 11:55 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: A good, inexpensive PS I've found
> Well, that blows me out of the water. I'm lucky if many of my Stamp
projects
> draw a couple hundred ma. The other AVR stuff draws even less.
>
> As far as the PC power supplies, we need to define "old." The really
> old
63
> watt and 100 watt XT / AT supplies did need a load. Not sure about the
later
> non-ATX models though.
>
>
Original Message
>
> > 1 amp load on the 5 Volt line will make most (that I have seen
> > anyway) computer power supplies come up.
>
> > The newer ATX power supplies need a load to let the monitoring
> > cirucit turn on the power supply.
> >
> > older power supplies don't need a load to start.
>
> > > Isn't it true that you always need some load on computer power
> > supplies to
> > > work/regulate.
> > > Seem to me I read something about this in N&V some time back. Also
> > > how
> >
> > > would you regulate/limit the current so not to blow
> > anything or in
> > > my case blind by the light when (not if) I short something out.
> > Just can't
> > > trust us mech types with electricity/
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
> and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/