Help with relay setup and transistor!

I have an arduino using the blink example trying to switch a relay, the relay is to manage a high powered device. I am having difficulty in a couple of areas and would love some advice:-

  1. I am using the TIP31CG transistor - I want to have enough voltage/current to switch this relay - http://www.maplin.co.uk/Module.aspx?ModuleNo=37514&C=SO&U=strat15. I don't know which legs are which on the transistor?
  2. Also is this transistor adequate to switch the relay linked above? What circuit would be required to switch it?
  3. Is a resistor required before the transistor on the circuit?

I have tried using the arduino relay pdf but am having some difficulty. Please help a newbie on a mission!

Cheers for your reply. I am literally brand new to understanding the arduino and circuit diagrams. I have no electrical engineering background so am learning fast!

The relay model that I have purchased is the N10AW. I am using the arduino/relay to control this snow cannon http://www.maplin.co.uk/Module.aspx?ModuleNo=226403 .

Got the datasheet details cheers, did look at a few but got it just there, cheers!

I think I need to use an external power supply on the arduino, I have a 2.2kw resistor connected to the base of the transistor, which has its collector connected to the relay. Sorry for the stupid question, but according to this http://www.arduino.cc/playground/uploads/Learning/relays.pdf, is the transistor being used to amplify the voltage or just act as a switch for the relay?

Also what is the main purpose of the resistor in the diagram?

Sorry for stupid questions, but Im trying to learn the in ands out, and the forum is a great resource!

The relay that you have purchased is for switching 12Vdc (N10AW)but the snow machine seems to be 230vac

I'd suggest taking a look at the remote controller that plugs in. The connector isn't shown but I wouldn't be surprised if it was a headphone jack. If you do investigate, of course be very very careful as it's possible that it's carrying 230Vac.

Yeah, cheers for looking. Noticed the relay was wrong when I was writing up! The remote control is actually wired direct to the mains power through a kettle lead.

I think im going to go down the remote controlled socket route and going to wire the arduino up to the the pcb in the remote control. Take away the whole 230VAC issue!

I would be interested in knowing the right way to wire this up going down the relay route, so if anyone has five mins, please msg!

Yeah, the remote control is just an on/off button attached to an external cable that you plug into the main unit. I was going to connect the relay to the remote control.

I am going to measure the voltage across the switch contacts on the remote control in the morning, and yes it is a simple on/off switch. I will report back, but you could be right about the power rating. Cheers for all the info, its greatly appreciated and thanks for your time guys!