Controlling a 12v dynamo via printer port

Anyone knows or has a circuit diagram regarding this?
We have this little project which we need to control 12v dynamo using a computer via printer port. It is just a simple on and off switch.
As of now we have 6v 5pin relay switch,2 power supplies, and we measured the voltage of our printer port by 3v and also a 4.5v.
By the way we are using Visual Basic 6 in XP OS.

we need to control 12v dynamo using a computer via printer port. It is just a simple on and off switch.

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1) Do you mean you have a dynamo generating 12V and you wish to connect that to a load via a switch?
2) How much current do you need to switch?
3) What is the coil current draw (or resistance) of the relay?