Time delay relay?

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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=6887
Printed Date: June 24, 2025 at 1:26 AM

Topic: Time delay relay?

Posted By: chuckyd
Subject: Time delay relay?
Date Posted: December 19, 2002 at 3:34 PM

I am in the process of hooking up a pair of strobe lights to my alarm. Unfortunately the two strobes flash at the same time. I would like them to flash alternately - similar to police lights. Is there an easy way to put a delay into one of the stobes for like a half second.

I think all I need is a delay circuit, but I know nothing about that or where I could get such a thing.

Please help, this is the one thing keeping from finishing the project.

-ChuckD

Replies:

Posted By: KBToys
Date Posted: December 20, 2002 at 6:45 AM

https://www.the12volt.com/installbay/display_topic_threads.asp?ForumID=5&TopicID=6746&PagePosition=1#thread

Posted By: capple
Date Posted: December 21, 2002 at 7:02 AM

use a cap and a resitor to charge it. Find the min voltage needed to switch the relay.

1 use 13vdc for your car and below values to the closes min turn on votage of the relay.

1	0.632
2	0.865
3	0.950
4	0.981
5	0.992

2 take your delay time divide buy the number next to the above value you used to find your min turn on.

3 take that value and divide by the cap value that will = the resistor value.

4 now paralle the relay to the cap and power it through the resistor from the output of the alarm

5 add more resitance for a longer delay use a pot to fine tune.

This should work