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need timed delay relay circuit, use induc

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=3100
Printed Date: August 13, 2025 at 7:21 PM


Topic: need timed delay relay circuit, use induc

Posted By: 2000vsm
Subject: need timed delay relay circuit, use induc
Date Posted: August 27, 2002 at 12:49 AM

ok.. how do i make a timed delay circuit?  say there is a 12v trigger, and that goes to a relay.. how do i make the 12v signal delayed like 7 seconds before it activates the relay?  do i use inductors or capacitors? i know inductors act as an short line when it's fully charged.. so i dunno? capactiors are the opposite....

help!




Replies:

Posted By: go2pac
Date Posted: August 27, 2002 at 11:34 AM
You would need more circuitry than capacitors. Inductors don't charge, capacitors do. Use our TR-7 universal trigger module. It has over  16 different features you can use.

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Karl

Pacific Accessory Corporation
Mobile Audio Interfacing Equipment
Connecting You to Your Music Since 1976



Posted By: HotRod53F100
Date Posted: August 28, 2002 at 5:20 PM
Go2Pac is correct, you need an RC circuit (resistive/capacitant). The circuit would consist on a CD4047, a resistor, a capacitor, a 2n2222 transistor, and a relay...some pretty basic stuff. You can vary the resistant value to change the time constant which alters the delay time. Sometimes it is much easier to buy something prebuilt and get it over with. Otherwise, check the net for a CD4047 or a 555 timer IC. You can also search for a mulitvibrator circuit.

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HotRod


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