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Momentary 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=27791
Printed Date: July 17, 2025 at 8:25 PM


Topic: Momentary Relay?

Posted By: bradleonard
Subject: Momentary Relay?
Date Posted: March 05, 2004 at 4:31 PM

I want to make a clutch cancel circuit for my Nissan Truck. I've already got it wired so that when I press a MOMENTARY Push button, it closes the clutch internlock circuit therefore doing the same thing as pushing the clutch in to start the truck.

I want to build a circuit that works similar to a Toyota Clutch Cancel Switch.

I will have a MOMENTARY push button that will send either a Postive or Negative to a relay that will close the Clutch Interlock circuit for a set amount of time.

Is there a relay that can be purchased that will close for a set amount of time (5-10 seconds?) or will this circuit work as described in this diagram work?

https://www.the12volt.com/relays/page5.asp#pts

If so, how do I adjust the amount of time that it stays closed.



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werd



Replies:

Posted By: Toru
Date Posted: March 05, 2004 at 5:37 PM
"Increasing the size of the capacitor will give you a longer output if needed."

The diagram you provided a link to tells you exactly how to do it.

What is does not tell you, nor I, is how long the the output will be for the given circuit, and what size capacitor to choose for a desired time period.




Posted By: capple
Date Posted: March 05, 2004 at 7:40 PM
bradleonard wrote:

I want to make a clutch cancel circuit for my Nissan Truck. I've already got it wired so that when I press a MOMENTARY Push button, it closes the clutch internlock circuit therefore doing the same thing as pushing the clutch in to start the truck.

I want to build a circuit that works similar to a Toyota Clutch Cancel Switch.

I will have a MOMENTARY push button that will send either a Postive or Negative to a relay that will close the Clutch Interlock circuit for a set amount of time.

Is there a relay that can be purchased that will close for a set amount of time (5-10 seconds?) or will this circuit work as described in this diagram work?

https://www.the12volt.com/relays/page5.asp#pts

If so, how do I adjust the amount of time that it stays closed.




I belive the DEI 528T will do it too. Try this it uses a transistor but is a real good time delay off.[image]https://ourworld.compuserve.com/homepages/Bill_Bowden/relay_i.gif[/image]





Posted By: capple
Date Posted: March 05, 2004 at 7:42 PM
capple wrote:

bradleonard wrote:

I want to make a clutch cancel circuit for my Nissan Truck. I've already got it wired so that when I press a MOMENTARY Push button, it closes the clutch internlock circuit therefore doing the same thing as pushing the clutch in to start the truck.

I want to build a circuit that works similar to a Toyota Clutch Cancel Switch.

I will have a MOMENTARY push button that will send either a Postive or Negative to a relay that will close the Clutch Interlock circuit for a set amount of time.

Is there a relay that can be purchased that will close for a set amount of time (5-10 seconds?) or will this circuit work as described in this diagram work?

https://www.the12volt.com/relays/page5.asp#pts

If so, how do I adjust the amount of time that it stays closed.




I belive the DEI 528T will do it too. Try this it uses a transistor but is a real good time delay off.[image]https://ourworld.compuserve.com/homepages/Bill_Bowden/relay_i.gif[/image]




Here is the write up on it [url]https://ourworld.compuserve.com/homepages/Bill_Bowden/page2.htm#relay_i.gif[/url]




Posted By: hboothe
Date Posted: March 06, 2004 at 2:14 AM

Use a 555 timer IC (e.g. LM555 by National Semi-conductor www.national.com, search for LM555, download and view the datasheet) to drive the low-current coil on your relay.  The 555 timer chip is fairly precise and can be adjusted with a resistor and a capacitor.  You would be interested in the monostable circuit example given in the datasheet.  Use your momentary switch (or other "trigger") tied to the trigger pin on the IC, then let it run it's output for the duration you calculate/want.  Technically speaking, the output is "high" (Normally Open, sort of, in relay-speak) for the set period of time, but there is another way to tie into the circuit to get the opposite "low" (Normally Closed, again, sort of, in relay-speak).  Here's a useful link on the chip and examples, etc.  Interesing that the same site but different page was posted by another person to your question: https://ourworld.compuserve.com/homepages/Bill_Bowden/555.htm

 The first (left-most) image of the circuit on that link that shows Monostable, or "one-shot", would seem to be your best bet.

HTH

--HC





Posted By: TeamMobileNyc
Date Posted: March 06, 2004 at 9:59 PM
528T should be perfect for you, I had to use it on a 328 covertible to open the top with it, you can adjust the duratio of the relay. Goodluck

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KFNYC





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