DPDT Relay Board - Function Board

[Jimmy]

Don't know if anyone has had much to do with the Relay Board Function Board, but according to the spec sheet, it appears to handle 240v AC. Is that correct? Can I switch 240 volts through this tiny function board?

Thanks.

[nick]

Note that it's only rated for 5 amps.  In the US at least almost nothing that runs over 120V draws that little current.

[Jimmy]

I did see it was only rated for 5 amps, which is fine for my use switching some lighting. But will it handle 240 volts?

[jason]

I've run 120v through one here to light a few incandescent bulbs.

If you do run 240v through it, make sure you are very careful about the exposed traces on the bottom of the relay board.

[Jimmy]

I'm always very careful with mains power as I've been 'stung' by it a few times as a kid. But as long as it handles 240 without any problems then I'm going to order a board now.

Thanks.

[nick]

Here is a datasheet for the relay:
http://relays.tycoelectronics.com/datasheets/p2.pdf

The data you need is on page 9.  Maxing switching capacity is 60 watts.  The 5 amp figure is peak, maximum sustained current is 2 amps.

Probably not terribly useful for lamps.
Nick

[jason]

If it helps, here is the schematic of the relay board.  Its a fairly simple circuit.   You could probably make you own capable of higher power if you wanted.

You did make a pretty cool setup back in this post: http://www.iobridge.net/forum/index.php/topic,255.0.html

Another option is a "solid state" relay.  They are a bit more expensive but may be better for your situation.  Most have screw terminals so you don't even need to do any soldering.  I've never personally used one, but looking at the specs, an IO-204 could drive one directly from it's digital output.
Here's an example:  http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PB545-ND

[nick]

I've had good results using the Functional Devices "Relay in a box" (RIB)

http://www.functionaldevices.com/pdf/RIBU1C.pdf

What I like is that they come in a UL-listed housing that attaches to a standard junction box so you can use them in a code-compliant way.  It's also interesting that they have both a high-voltage and low-voltage coil in the same unit.

You can get them on Ebay for about $15.

What you could do is use the ioBridge relay to power this relay.  The one question is what voltage level to use.  There is a version of the RIB that uses 240VAC for the coil, the RIBH1C, which you could switch with the ioBridge relay.  I think it would be safer to use the low voltage coil of the relay.  The problem is that it takes a minimum of 10V for the low voltage coil so you would need to add another power supply.

Nick

[uknative]

I see on the circiut schmeatic there is a "2222" transistor, would it be possible to substitute a "3904" transistor?
I only ask because that is what I have on hand, and I have a grab bag full of relays that I got a while back.

[jason]

I would think a 3904 would drive most small relays (> 100mA).  A 3904 is an NPN transistor therefore it will work with the circuit above.  Be careful trying to drive a large relay with it.  I'm not sure how much current they can handle.   

[uknative]

Thanks Jason. It is a small relay (5v coil) almost exactly the same as the one on your relay boards. I'll let you know how it goes.