I'm trying to add a Foreign Key to a table, but database, Sql Server 2005, does not like it.

It says that columns do not match an existing primary key or unique constraint. 

How can I find the columns in question so I can delete/change them and add the foreign key?


Question: Can I use the following power supply as a constant fixed current source?
Answer: Yes, you can use it exactly as a constant current source (within its limits).  You set the Voltage to a maximum (with the knob - be careful that it can go to a maximum) and Current to a minimum (same warning) and then hook up the circuit and ramp up the current limit until you hit the value you want.  If the power supply is wired correctly the voltage displayed will be the voltage across the load, from which you can measure the load value.

An Ideal current source will change it's output voltage to conform to the requirements of the external circuit and will develop sufficient voltage to ensure that the current is constant.  Up until the point that it can't.  Like for example running unto the upper rail.  You can't put out a voltage that is higher than what the Power supply itself can supply (but this may be higher than what the power supply puts out when in voltage mode).

You will need to monitor the meters to make sure that it makes sense (not at the limits of voltage ranges) and regulation and control can be marginal at the minimums.