Would you consider "intelligent" MOSFET's? Would give you a space saving ov=
er=20
relay, but possibly more expensive. One I've recently used (for driving sol=
enoids) is=20
the ST Microelectronics VNQ690SP, 4 channel high side solid state relay, no=
minal=20
10A, 36V, fully protected.

http://www.st.com/internet/automotive/product/75329.jsp
http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERAT
URE/DATASHEET/CD00003299.pdf

On 6 May 2011 at 11:34, PICdude wrote:
> Good point, but somehow I'm thinking/expecting a mosfet switching a =20
> larger load such as a solenoid failing easier than one switching a =20
> small relay.  Of course, the choice of mosfet in each situation would =20
> make a big difference.
>=20
> I need to switch 12V 10A.  The cost of any average MOSFETs that can =20
> handle this, is similar to that of the relays.
>=20
> Cheers,
> -Neil.
>=20
>=20
>=20
> Quoting Michael Watterson <mike@radioway.org>:
> > On 06/05/2011 16:53, PICdude wrote:
> >>    I'm considering on-board
> >> relays vs. MOSFETs.
> >
> > But you need MOSFETS or BJTs anyway to drive the relays.
> >
> > If you choose suitable MOSFETS, snubber and/or diode etc driving the
> > solenoids direct can be more reliable.
> >
> > But there is a big difference between say 12V 500mA solenoids and 110V
> > 10A ones.
> >
> >
> > You don't say what voltage/current of solenoid.
> >
> > You can also monitor the MOSFET output via resistor divider (even OR
> > them all with diodes)  and have an alarm or something if a FET fails.
> >
> > 900V 10A MOSFETs are < $2
> > --
--=20
Brent Brown, Electronic Design Solutions
16 English Street, St Andrews,
Hamilton 3200, New Zealand
Ph: +64 7 849 0069
Fax: +64 7 849 0071
Cell: +64 27 433 4069
eMail:  brent.brown@clear.net.nz


--=20
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