Linear supply you can chain to get +/-12V with only positive regulators ?

[tnt]

Imagine I want to do two independent linear supply providing +12V each. They're both using let's say 7812 and using different secondary winding (and so they're floaint wrt to each other).

Can I just connect the GND of one to the output of the other to have -12V 0 +12V ?

What's the impact / difference to using a 7812 and a 7912 for eg ?

[IanB]

As long as each supply is independent and isolated you can use a 7812 for both and connect them in series and it will work fine.

[penfold]

The case you speak of is a prime candidate for using a 78xx series regulator and connecting just as you say to get dual rail supply.

If the 0V lines are common at the transformer then you need a regulator with its pass element in series with the -ve supply rail (else you're end up messing up the opposing rail) hence the 79xx series