Relay or similar between 5v dc - 240v ac.

[Pepperisit]

I am getting quite confused at the moment. I am a complete novice (so dumb down your wording please!)
I wish to switch a 240v ac light (standard uk) with the output of a USB from my tv or pc.

Hence when tv on, light on.

I have been googling and cannot find any 5v relays that can handle that high voltage.

Other places have suggested Triacs or a contactor.

but I dont really understand what would be best.


MY other idea is to butcher one of these countdown plugs
http://tinyurl.com/bvnn3xl
because it can switch 240v, 13a and the internal timer circuit (probably) would be using 5v?

Any help Greatly appreciated.

 

[jackorocko]

Well one way would be to use the 5V usb signal to drive a transistor that will be able to drive a bigger relay that can handle the 240V.

There probably is a more elegant solution, recently others have talked about cords that will turn off printers etc. when the main computer is turned off. Maybe one of these would suffice for your application but I don't know the name of the device. I think Harald Kapp posted it, maybe you can PM him. Or maybe not with only 1 post.

 

[davelectronic]

Hi there Welcome to the forum.
I have one or two ideas, but not sure on how you want to interface this with the light ( connect between the two ) wires, or wireless. Both ways need separate solutions.

 

[BobK]

I find literally hundreds of relays with a 5V coil and 240V AC contacts on Mouser.com

There are also solid state releays, and raw opto-isolated triac ICs that would do the job.

Bob

 

[Pepperisit]

Wired is fine.

Oh okay I couldn't find them but then again my knowledge of electronics shops is none... and in my defence google didn't offer any 5v relays!

Solid state relay? and opto-isolated triacs?
Which would be the best/easiest/cheapest etc circuitry?

 

[(*steve*)]

go to http://mouser.com

type in "relay" in the search box and hit search

scroll down to "electromechanical" and click on "relays and I/O modules"

Pick the sort of relay you want (general purpose sounds fine)

Select a coiul voltage of 5V (there are actually 3 that match closely) and click on "apply filters"

apply other filters as required (possibly contact rating and contact form) to narrow down the selection.

Scroll through the results.

a quick scan showed me this one which would seem to fit the bill (and it's cheap)

 

[davelectronic]

You wont do much better than that in terms of current consumption and specifications in the power ratings, an ideal relay.