[MAMS] relay driver

[Zack Widup]

No, not if it continues to draw current. In the HP33311C I've been
mentioning, there is evidently an internal relay or switch that disconnects
the pin that was just grounded when you switch it. It draws no current as
long as that pin is grounded. When you ground the other pin, it switches
the relay and also disconnects that pin. So it's a whole different
arrangement.

Zack W9SZ


On Fri, Sep 7, 2012 at 3:40 PM, Danny Pease <dpease at adams.net> wrote:

> I see 225 mA of steady current when 13.6 VDC is applied. The case does warm
> up noticeably after 20 seconds or more and is almost hot after 90 seconds.
> I
> don't think I will want to leave the DC applied all the time.
>
> Danny NG9R
>
>
> -----Original Message-----
> From: mams-bounces at mailman.qth.net [mailto:mams-bounces at mailman.qth.net]
> On
> Behalf Of Dr. Gerald N. Johnson
> Sent: Friday, September 07, 2012 1:30 PM
> To: mams at mailman.qth.net
> Subject: Re: [MAMS] relay driver
>
> 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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