how clean is power through a 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=91086
Printed Date: May 03, 2024 at 8:31 AM
Topic: how clean is power through a relay?
Posted By: spyderbyte
Subject: how clean is power through a relay?
Date Posted: February 27, 2007 at 9:34 PM
It looks like integrating reverse cameras is a common topic on here.
I was considering a set up like this one, splicing my reverse lights for pin 86 to trigger.
How much noise will the relay introduce into the system?
Are there inexpensive AV switchers that can be triggered by a remote wire to use instead?
Thanks!
Spyderbyte
Replies:
Posted By: hotwaterwizard
Date Posted: February 28, 2007 at 7:56 AM
It would be better to get a VW relay with a Metal Case and ground the case to ground with a metal hose clamp and an L bracket.. The metal case will shield the Relay and it will not pick up Alternator interfearance.
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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: hotwaterwizard
Date Posted: February 28, 2007 at 8:08 AM
Crutchfield has a switcher for Automotive use. https://www.crutchfield.com/S-1dbHCTGSW6n/cgi-bin/ProdView.asp?g=81600&I=469MPSS4 
------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: spyderbyte
Date Posted: February 28, 2007 at 3:36 PM
hotwaterwizard wrote:
It would be better to get a VW relay with a Metal Case and ground the case to ground with a metal hose clamp and an L bracket.. The metal case will shield the Relay and it will not pick up Alternator interfearance.
Will this be enough to keep the signal clean? The relay itself won't introduce any interference or dropped signals?
hotwaterwizard wrote:
Crutchfield has a switcher for Automotive use.
Would I be able to run video signals through that instead? To clarify, I'm only looking to switch video sources, audio will be continuous. I'm really just searching for a fancy 5 pin relay (if I even need fancy).
Thanks!
Spyderbyte
Posted By: hotwaterwizard
Date Posted: March 01, 2007 at 8:38 AM
There is one way to find out. When in doubt, try it out ! ------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: spyderbyte
Date Posted: March 01, 2007 at 3:18 PM
hotwaterwizard wrote:
When in doubt, try it out !
I would if I currently had any of the other components of my planned set up. I'd much rather find out if something isn't possible BEFORE I jump head first into another fairly ambitious (and reasonably spendy) project.
Spyderbyte
Posted By: KPierson
Date Posted: March 01, 2007 at 3:36 PM
I'm using an industrial 12 4pdt relay to switch between my OEM navi and my laptop display and I'm not getting any noise. The only noise you need to worry about the relay adding is when it clicks on and off. As long as the voltage is stable across the coil noise should't be an issue, or at least it isn't in my case.
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Kevin Pierson
Posted By: spyderbyte
Date Posted: March 01, 2007 at 4:15 PM
4pdt? Are you running s-video cables?
I like the news though, where did you get this relay?
Thanks!
Spyderbyte
Posted By: hotwaterwizard
Date Posted: March 01, 2007 at 10:09 PM
spyderbyte What kind of connection do you need? RCA BNC S A relay is what $10 and a Double ended Female RCA what $5 Hmm $15 sounds like a fairly ambitious (and reasonably spendy) project.
------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: spyderbyte
Date Posted: March 02, 2007 at 12:00 AM
hotwaterwizard wrote:
What kind of connection do you need?
Component video. I only mentioned s-video because KPierson's 4pdt relay seemed like overkill.
hotwaterwizard wrote:
A relay is what $10 and a Double ended Female RCA what $5
Hmm $15 sounds like a fairly ambitious (and reasonably spendy) project.
I was referring to the media player, camera, and screen I was planning to hook up through this relay. I want to make sure I'll have good video quality before I purchase everything.
Therefore I can't "try it out" and am looking for people who have.
Thanks
Spyderbyte
Posted By: hotwaterwizard
Date Posted: March 02, 2007 at 7:40 AM
My mistake . Sorry if I insulted you in any way. I thought you already had the system. Now I see what you are talking about. ------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: KPierson
Date Posted: March 02, 2007 at 8:43 AM
spyderbyte wrote:
4pdt? Are you running s-video cables?
I like the news though, where did you get this relay?
Thanks!
Spyderbyte
RGB+S so there are four wires (red, green, blue, sync). Have you ever opened up a relay before? If you haven't, inside you will just find switch contacts. There isn't much difference in running signals through a set of switch contacts then running the signal through wire. I found the relay in my garage, sorry I can't help you on that one! I would guess that grainger would sell them, as well as other industrial supply places (McMaster Carr etc.). ------------- Kevin Pierson
Posted By: spyderbyte
Date Posted: March 02, 2007 at 11:07 AM
hotwaterwizard wrote:
My mistake . Sorry if I insulted you in any way. I thought you already had the system. Now I see what you are talking about.
It's all good, I'll try to be more clear next time.
KPierson wrote:
Have you ever opened up a relay before? If you haven't, inside you will just find switch contacts. There isn't much difference in running signals through a set of switch contacts then running the signal through wire.
I haven't personally opened a relay, but I've seen pictures. I understand that it just switches contacts, but I was wondering about the electromagnet that causes them to switch. I suppose at worst it would only induce interference when it's powered, and I think I would be able to stand my reverse monitor being a little fuzzy.
I just wanted to make sure a basic automotive dpdt relay would work, and I didn't need a fancy solid state or other specialized relay. It sounds like it will, so I'll charge on ahead with my project.
Thanks everyone!
Spyderbyte
Posted By: hotwaterwizard
Date Posted: March 02, 2007 at 11:52 PM
Posted By: spyderbyte
Date Posted: March 03, 2007 at 12:09 AM
I don't understand how running the current right past the electromagnet (twice?) doesn't induce interference, but if it works I won't question it.
Spyderbyte
Posted By: Hymer
Date Posted: March 06, 2007 at 5:06 PM
I've done it, not with component stuff, but standard rca video cables, worked fine... no probs at all, switched between sat tv, drivesoft, dvd player, backup cam , and a nav setup...
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Tire Proz Stillwater Mn
High End Restyling and Comlete Repair
Posted By: Ravendarat
Date Posted: March 07, 2007 at 1:18 AM
Im using several relays in my video system right now and am getting zero noise through any of my sources on any of my screens. Im just using standard 5 pin Bosch relays with plastic casings, no problems.
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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: hotwaterwizard
Date Posted: March 07, 2007 at 8:00 AM
spyderbyte wrote:
I don't understand how running the current right past the electromagnet (twice?) doesn't induce interference, but if it works I won't question it.
Spyderbyte
I suppose you are refering to EMF caused by the flux lines created by the magnitism of the coil when it is energized. Maybe it is at a frequency that is not picked up by the low voltage shielded wires that are used with RCA connections. I would suggest using a Diode on the coil to reduce the risk of the EMF pulse being picked up as the field of the coil colapses. ------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
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