latching relay

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=89844
Printed Date: June 08, 2024 at 5:12 PM

Topic: latching relay

Posted By: sub95
Subject: latching relay
Date Posted: January 31, 2007 at 5:11 PM

Hi, I am trying to get a neg pulse to stay constant 12+ but also turn off with the neg pulse, i found this pic but dont understand what looks to me is a push button on off?.

And where would i put the neg input to turn relays on/off..

Thanks

Replies:

Posted By: sub95
Date Posted: January 31, 2007 at 9:30 PM

Here is the pic i was talking about,
posted_image

Posted By: sub95
Date Posted: February 02, 2007 at 10:56 AM

Hi, i looked and tried to make the latched on/off output with momentary pulse with Diodes. using Diodes1N4001, this is a single neg pulse button i am using to activate relays.

But when i tried doing this i had to leave the #1 relay #87A unhooked to turn on the light, then i had to touch 87A to the other side of it which is #3 relay 85 and #4 relay # 87, it sounds like it un latches one of the relays when i do this? now i push the key pad light turns off? Anyone know why this is? i followed the diagram to a tee.

Thanks

Posted By: hotwaterwizard
Date Posted: February 08, 2007 at 10:11 PM

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: hotwaterwizard
Date Posted: February 08, 2007 at 10:34 PM

Add an extra relay and here is what you get.

posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: dualsport
Date Posted: February 17, 2007 at 10:33 AM

Not sure what your application is, but if you need this to control something that's going to be on all the time while on battery power, you might be better off using solid state circuitry to do it. If this is for something that's AC powered, then the drain from the relays won't be a concern.

Posted By: hotwaterwizard
Date Posted: February 17, 2007 at 8:13 PM

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: dualsport
Date Posted: February 18, 2007 at 11:48 AM

Try this to get a toggling output from a single pulse input-
If your input pulse isn't clean and free from glitches, it may be necessary to add some filtering to the input to keep it from toggling multiple times on the single pulse.
You can use different output stages depending on what you need to drive with it; those two transistors should be limited to a half amp or less.

Each time the input is pulsed, the U1A Q output should toggle between 0V and 12V. Since that output can supply only a relatively small amount of current, that line is used to turn the transistors in the dotted boxes on/off, which can handle more current. Which one you use depends on whether you want a ground switch output or a 12V output. Just use larger transistors if you need more drive current.

The D1 and D2 are just to help protect the chip input in case the drive signal has spikes on it; if it's a clean input, they aren't needed. If you're driving relays with the transistors, it'd be good to add suppression diodes to protect them from the turn off spike.

posted_image