Depends very much what circuit you will use to drive the coil forward/rever=
se. In=20
case of a full bridge driver using 4 x MOSFET's the internal parasitic diod=
es will=20
direct the EMF back to the supply rails no matter what polarity the EMF is.

If that not applicable then consider limiting the EMF to a practical/safe l=
evel with an=20
AC TVS diode, varistor, or 2 x zener diodes in series (Vz + 1 x forward dro=
p, either=20
direction).

If speed is relevant, the higher you let the EMF rise the quicker the magne=
tic field=20
will colapse and the contacts respond.

On 30 Sep 2013 at 7:32, alan smith wrote:

> Normally with a relay, you would simply put a diode across the coils to s=
nub the EMF.
> =A0
> With a single coil latching relay, where you swap the polarity to latch/u=
nlatch thats not going to work very well.
> I've done a bit of searching and have yet to see an example of how to snu=
b something like this, so asking
> the list if anyone has an idea?
>=20
> --=20
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>=20

--=20
Brent Brown, Electronic Design Solutions
9 Titoki Place, Pukete,
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




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