Delay to energise 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=24996
Printed Date: May 15, 2025 at 9:58 PM

Topic: Delay to energise relay

Posted By: timtay
Subject: Delay to energise relay
Date Posted: January 21, 2004 at 9:53 AM

Please see attached diagram.
I would like to delay the +12V supply which energises the relay coil of about 0.5 to 1.0 seconds. The coil is energised when the car door opens, and then after a short delay the circuit (blue wire) is broken.
What do I need to add (in the dotted red box) to achive the desired result? - Is it a combination of resistor & capacitor?, if so what values & how are they connected?
Please help, thanks

-------------
Tim Taylor

Replies:

Posted By: terryr
Date Posted: January 21, 2004 at 1:25 PM

The 12volt has a page on that.

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

Posted By: timtay
Date Posted: January 22, 2004 at 6:23 AM

Thanks terryr
https://www.the12volt.com/relays/page5.asp
Is the 3rd diagram on the above page the correct one? 'Pulsed to Steady Output' - If it is, I can't see how it achieves a delay as there is a direct connection to pin 86 on the relay, and the current dosn't 'go through' any components, except for the diode.
Shouldn't the current flow go through a capacitor & resistor connected in parallel or something?.
Looking at the 1st diagram, 'Constant to Momentary Output' it uses a 1kµf capacitor & a 10k resistor, to achieve a 0.5 sec delay - is this correct?
Thanks for your help
Tim

-------------
Tim Taylor

Posted By: terryr
Date Posted: January 22, 2004 at 1:16 PM

As I said in the PM do want Delay then On, or On then Off?

Have you seen this bosch relay book? It may help.

https://www.netwiz.net/~jds/files/bosch.pdf