I need a relay that controls 120v with 12v

[bad_idea]

Long story short- I need to control a 120v radio receiver with a 12v signal.

Long story- I have the lower dash panel from my old 79 Camaro mounted to my workbench with the car radio mounted in that. I have a computer power supply providing the needed 12v to power the car radio. The audio signal from the car radio is then routed to a home stereo receiver that powers the speakers in the garage. The car radio didn't have the oomph to drive the speakers. Currently I have the car radio IGN feed wired hot at all times so I have to hit the OFF button on the car radio to shut it off. Not a big deal, but the radio display lights stay on all the time. I also have to turn the home receiver on and off every time I turn the radio on.

To remedy these two issues I have an ignition switch that I want to switch the IGN feed for the car radio with. I also want this same switch to control the home receiver. I envision a relay controlling an outlet mounted inside the radio "drawer" with the home receiver plugged into that. The home receiver is an older analog unit, so controlling it in this manner shouldn't be an issue. To clear this up some I included a couple pictures below.

Disregard the cluttered bench. Or the half-finished corrugated steel wall covering. Or the rusty workbench waiting for a coat of paint. Or..... Damn, I've got to many projects on going.

 

[Steevo]

Radio Shack used to carry a pretty good selection of relays, with contacts rated up to 125v and choices of coil voltage either 12vdc or 125vac.
I haven't bought one in a while, and Radio Shack is a lot less of an electronics store than it used to be, so you never know what they might have.

You could use a driving light relay from an auto parts store. The contacts in those are stout because of the high amperage they have to pass.

 

[bad_idea]

I think I'll hit up Radio Shack tonight. I didn't realize that was a readily available relay. If they don't have one anyone got another source for one? I tried searching the internet but came up dry.

 

[Steevo]

Here are a couple:
http://www.allelectronics.com/make-a-store/item/RLY-2012/12-VDC-D.P.D.T.-10-AMP-RELAY/1.html

http://www.allelectronics.com/make-a-store/item/RLY-351/12V-SPDT-30-AMP-AUTOMOTIVE-RELAY/1.html

http://www.grainger.com/Grainger/OMRON-Square-Base-General-Purpose-Relay-5ZH12?Pid=search

 

[Stuart in MN]

I'd try Automation Direct, what you need is commonly called an 'ice cube' relay: http://www.automationdirect.com/adc...QL2_-z-_QL4_-z-_QM2_-z-_QM4_Series)/QL2N1-D24

Some other online sources include Mouser Electronics, Digi-Key, and Newark Electronics.

I looked at the Radio Shack site, and there are two problems: 1) the tech info is nearly nonexistent and 2) it appears all the relays that may be appropriate for this application are sold on their website only. If you have a Radio Shack nearby I suppose it's worth a try, but you may not find what you need.

 

[PRH44]

You can purchase a 12VDC coil relay with 10 amp 125 volt rated contacts readily.
You will need a DPDT relay. I like to use the 8 pin with a socket AKA " octal base"
I use newark electronics very fast and affordable.
plug in style you can use female plug crimps or do what I prefer and purchase a base with screw terminals

http://www.newark.com/magnecraft/782xbxm4l-12d/power-relay-dpdt-12vdc-15a-plug/dp/18C1606

Lots of options local electrical supply house
On line Allied electronics, Mouser, Mcmaster carr

 

[Stuart in MN]

I forgot to mention - the kind of relays several of us have posted can be wired up directly, but they're really designed to plug into a socket that has screw terminals for the wire connections. The socket will cost you a few bucks more on top of the cost of the relay itself.

 

[lilredex]

The easiest way to do it, is to plug both your stereo and the computer power supply into a power bar, then switch that.

A common relay found on furnaces is a White-Rodgers 8A05A-*** and it comes with its own self contained 24V triggering circuit...........use your ignition switch to complete that 24V circuit.

Around here furnaces are tossed out regularly, and many have that relay on them. You might even find a free one. They are very stoutly made and last forever.

http://www.emersonclimate.com/Documents/White-Rodgers/catalog_06_pages/Cat_06_pg0145.pdf

 

[bad_idea]

The easiest way to do it, is to plug both your stereo and the computer power supply into a power bar, then switch that.

Thought of that. The car radio has a BAT feed that is suppose to be hot at all times to save the presets.

I found the necessary relay at Radio Shack. Tomorrow after work I will wire the whole shebang up and see if I set the garage on fire. Thanks again guys.

 

[bad_idea]

Why do I need a DPDT relay? I assume to interrupt both of the 110 leads. But why? All of the light switches in my house only interrupt the hot leg.

 

[BFBOB]

Altronix. They make a variety of very handy relays mounted on circuit boards with barrier strip teminals. Marketed to the alarm industry, and probably others. The RB5 is probably a good choice for you.

 

[Stuart in MN]

Why do I need a DPDT relay? I assume to interrupt both of the 110 leads. But why? All of the light switches in my house only interrupt the hot leg.

You don't, a single pole will work just as well. However, the extra set of contacts can be handy if you want to switch something else, and the price shouldn't be much different.

 

[Dustball]

Since we use these at work for industrial control panels, I can say these will work for you-

AEG LS07.22-msw (2 NO/2 NC)
AEG LS07.40-msw (4 NO/0 NC)

The -msw suffix stands for 12VDC coil.

 

[2manytoyz]

A simple way to do this is with a solid state relay. I bought a number of these from Ebay.

Under $5 on Ebay, free shipping. http://www.ebay.com/itm/New-Solid-State-Relay-SSR-25DA-25A-250V-3-32VDC-/260945364922?pt=LH_DefaultDomain_0&hash=item3cc18e47ba