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From: kristi@hpscdc.HP.COM (Kristi Bittner)
Newsgroups: sci.electronics
Subject: Re: Latching Relay - does such a thing exist
Message-ID: <5770020@hpscdc.HP.COM>
Date: 20 Sep 89 21:33:57 GMT
References: <3558@dgis.daitc.mil>
Organization: Hewlett-Packard, Santa Clara Div.
Lines: 25


>I have an application where I need to activate a SPDT set of contacts
>such that the toggle action does not release after the coil voltage is removed.
>And I should then be able to toggle back the contacts with another pulse.
>The best analogy is a SPDT RELAY that latches in the activated position until
>another pulse comes and toggles it again.
>If anyone knows of such a device, or can think of a way of building one....

>Curtis C. Generous

Yes, latching relays exist.  I've used ones from Aromat Corp. (a US
division or subsidiary or whatever of Matsushita)  They have a SET
coil and a RESET coil, each of which needs approx 10mS pulse.  I'm 
sure other relay vendors make these.

If you want to have just a single signal line doing the pulse (toggle
effect), it's a little tougher.  You either have to have a circuit
that will steer the pulses to one coil or the other, or else some of
the relays now have ic's built into them, that do the steering for
you.  (I'm sure this handy little feature costs...)

Kristi Bittner

hpscdd!kristi@hp-sde
hpscdd!kristi@hplabs