My guess would be they chose 10 volts because it is between the 5 volt
TTL supply rail and the  =20
 +/- 15 volt rails opamps typically use.  But, that's just a guess.

 And assuming you use signals that doesn't rail the opamp, it probably
won't make any discernable difference
 from an experimenters point of view.  You could probably measure a
slight difference in power consumed,=20
 but if you did, it would be so small as to be inconsequential.=20

 You could even use +/- 5 volts if you so chose, but then again, you'd
have to have some sort of negative=20
 power source.   Building a +/- power source is a realatively simple
operation, especially if you use linear
 regulators.  However, building a simple switcher for complimentary
oltages isn't that much more difficult.

 As a matter of fact, you could use two 9 volt batteries to use the
analog board itself to design a=20
 regulator, and then build upon what you learn to design and build your
own power supply.  This would not=20
 only give some justification for buying the board in the first place,
it would give you practical=20
 experience and practice with the various circuits.

 What ever you do, have fun and learn.  You'll never know when you'll
need the technical skills you will=20
 acquire from the experiments you perform.


 Regards,

 Jim

> -------- Original Message --------
> Subject: Re: [EE] Analogue development board
> From: IVP <joecolquitt@clear.net.nz>
> Date: Mon, December 19, 2011 3:09 pm
> To: "Microcontroller discussion list - Public." <piclist@mit.edu>
>=20
>=20
> > a +/-9v battery supply will work
>=20
> There's probably nothing too fussy about 9 or 10. Maybe they've
> chosen 10 for maths, or a recommended supply
>=20
> Once the novelty of replacing batteries wears off it'll end up unused.
> It would be much better, and more economic, to use a transformer
> or AC wallwart for a long-life stable voltage
>=20
> RS have +/- 12 and +/- 15 DC/DC converters. No +/- 10 seen
>=20
> http://newzealand.rs-online.com/web/c/power-supplies/power-supplies-inver=
ters-dc-dc-converters-generators/dc-dc-converters/?sort-by=3Ddefault&sort-o=
rder=3Ddefault&applied-dimensions=3D4294880637&lastAttributeSelectedBlock=
=3D4294958691
>=20
> Reasonable at 10s of mA, gets pricey over 100mA, and you need
> a DC source
>=20
> For the price you could put together a chassis-mount transformer,
> bridge and regulators and get exactly what you want
>=20
> Joe=20
>=20
> --=20
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