[Noisebridge-discuss] N00b question - changing power supplyvoltage

[Sean Cusack]

Wow...I am retarded. The 2 in series does sound like a good idea to try
first, but I'll pick up some voltage regulators too so I can melt some shit
like crazy, and then figure out how to not do it again :).

BTW, I thought TE coolers *were* semiconductors:
http://en.wikipedia.org/wiki/Thermoelectric_cooling (although an individual
peltier junction may not be though - it could just be an inverse
thermocouple, right?). Jim - I'll try out the parallel rectifiers...these
are the power supplies that I picked up from NB's E waste bin before they
got tossed...and I have like 15 of them. In other words, if I really fuzz a
couple of them, I've got some spares.

Sounds like I should give this a spin at NB instead of my lab so people can
watch the fireworks :).

Sean

On Thu, Jul 1, 2010 at 8:07 PM, jim <jim at well.com> wrote:

>
>
>   maybe you could put two peltier junctions in series?
>
>   as to parallel rectifiers, i'd like to know if that
> works. i wouldn't do it except as an experiment--every
> semiconductor junction is a little bit different from
> every other. the junctions in one rectifier may or may
> not be nearly identical, depending on the manufacturing
> process, but it's a pret' near sure bet the junctions
> in a second rectifier will be different from those in
> the first. therefore there's a chance that one rectifier
> will be "favored" and pass more current, possibly lots
> more current. one way to mitigate that possiblity is to
> put a very low value, relatively high wattage, power
> resistors in series with each rectifier (identical
> values, of course, and test to be sure their resistance
> really is just about exactly the same): 0.5 ohms at
> 10 Watts should work.
>
>
>
>
> On Thu, 2010-07-01 at 19:29 -0700, Lee Sonko wrote:
> > Since a peltier junction is a big hunk of metal (and not a
> > semiconductor), and it won't draw variable amounts of power, I guess
> > you don't need any capacitors to smooth out the power.
> >
> >
> >
> > Your 24volt 4.5 amp power supply will only be able to supply 12 volts
> > 4.5 amps with a voltage regulator. It won't be able to supply more
> > amperage.  Also note the voltage regulator I pointed to isn't rated
> > for 4.5 amps. The regulator is liable to overheat. I -think- it's ok
> > to put 2 voltage regulators in parallel to up the amperage ability but
> > I don't know for sure.
> >
> >
> >
> >
> >
> > Have fun freezing/burning the castle!
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > ______________________________________________________________________
> > From:noisebridge-discuss-bounces at lists.noisebridge.net<From%3Anoisebridge-discuss-bounces at lists.noisebridge.net>
> > [mailto:noisebridge-discuss-bounces at lists.noisebridge.net] On Behalf
> > Of Sean Cusack
> > Sent: Thursday, July 01, 2010 6:03 PM
> > To: Ryan Castellucci
> > Cc: <noisebridge-discuss at lists.noisebridge.net>
> > Subject: Re: [Noisebridge-discuss] N00b question - changing power
> > supplyvoltage
> >
> >
> >
> >
> > Awesome - thanks guys!
> >
> > I'm going to try to use this guy to power a peltier cooler (I've got a
> > sweet idea here depending on how well I can get this doo-hickey to
> > work). It takes 12V at up to 9A, but from the reading I've been doing,
> > it looks like you want to stay away from the top value of amperage
> > anyways. I'll give it a spin with just the 4.5A first to see how it
> > works.
> >
> > Based on what I'm seeing below, if I use 2 voltage regulators in
> > parallel, it looks like that should handle the current without a
> > problem. I can totally drop in a cap after the fact to smooth out the
> > current. Ryan - I'm considering doing an ATX PSU mod too...I've got an
> > extra one laying around.
> >
> > Sean
> >
> > On Thu, Jul 1, 2010 at 5:05 PM, Ryan Castellucci
> > <ryan.castellucci at gmail.com> wrote:
> >
> > How much current are you drawing?  TBH, you should really just go to
> > weird stuff and pick one up for a few dollars.  Another option would
> > be converting an ATX power supply to a bench supply.
> >
> >
> > On Thu, Jul 1, 2010 at 1:57 PM, Sean Cusack <sean.p.cusack at gmail.com>
> > wrote:
> > > Hey kids -
> > >
> > > So, I've got a relatively simple dilemma that I sure pops up all the
> > time
> > > for those of you that are way better at electronics than me. I've
> > got a
> > > power supply providing a fixed 24V @ 4.5A, but I only want to use
> > 12V of
> > > that for my circuit. I originally thought I could lower the voltage
> > using a
> > > potentiometer, but because the power is so high, they all cost some
> > serious
> > > bank. Is there another (not necessarily analog) solution to changing
> > voltage
> > > and/or amperage through a circuit that is cheap to build?
> > >
> > > Sorry if this one is likely obvious - but everyone can blame Mitch
> > for
> > > getting me way to into electronics for my own good :).
> > >
> > > Sean
> > >
> >
> >
> > > _______________________________________________
> > > Noisebridge-discuss mailing list
> > > Noisebridge-discuss at lists.noisebridge.net
> > > https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
> > >
> > >
> >
> >
> >
> >
> >
> > --
> > Ryan Castellucci http://ryanc.org/
> >
> >
> >
> >
> >
> > _______________________________________________
> > Noisebridge-discuss mailing list
> > Noisebridge-discuss at lists.noisebridge.net
> > https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>
>
>
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