> 	I think in a proper lab setting, they have a spot welder to
> bond the two conductors together but I don't understand how the
> differential is formed.  One conductor is going to be pretty much the
> same temperature as the other because they are tacked or bonded
> together.

There are two points of importance in a thermocouple. The first one is
where the two dissimilar metals are joined. The other end of the wires
is the other one.

Get one of these ends hot and one cold and you will have a current flow.

The problem is that you have to keep the temperature differential.
-- 
D. Jay Newman           ! Polititions and civilations come and
jay@sprucegrove.com     ! go but the engineers and machinists 
http://enerd.ws/robots/ ! make progress
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