[MAMS] relay driver

[Zack Widup]

The HP33311C that I mentioned latches when one of the two pins marked "-"
is grounded. That pin can then either remain grounded or opened up and the
relay will remain latched in that position until the other pin is grounded.
Then that pin can either remain grounded or opened up, etc.

I have another latching SMA relay that is a little more complicated. I
haven't used it yet.

73, Zack W9SZ


On Fri, Sep 7, 2012 at 1:29 PM, Dr. Gerald N. Johnson
<geraldj at weather.net>wrote:

> There are at least a couple two coil latching relay schemes. One is just
> two coils tha you only need to apply a pulse to for a short period and
> the relay mechanically or magnetically latches. I don't see a
> restriction in the catalog that requires power be removed from the coil
> right away except that the current of some latching versions at 12 volts
> is 230 ma and the same relay not latching (fail safe) is 195 ma, so
> there's more heat in the relay with continuous coil power. Then, of
> course, it takes applying power to the other coil to change the relay
> position. Coils often have one wire in common and are polarity sensitive
> so that prevents some simple drive circuits based on conventional relay
> drive.
>
> Some Dow-Key also have a self cutoff circuit, so keep the power
> consumption low by taking care of interrupting the coil current on their
> own to make the drive circuit simpler.
>
> I have portions of a recent Dow-Key relay catalog on my other computer
> but need a model number to know what you have and how to drive it.
>
> 73, Jerry, K0CQ
>
> On 9/7/2012 12:47 PM, Danny Pease wrote:
> > I picked up a two coil 12 volt latching DowKey SMA relay and am looking
> for
> > simple suggestions for using it or I would be glad to trade it for a non
> > latching SMA relay, 12 or 24 volt.
> >
> > Danny NG9R
> >
> >
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