Probably a very basic DC question

[atn_prabhu]

Can the discussion knowledge be applied for a practical requirement ?

I have a practical requirement. My Klipsch speaker's power supply (+-18V 836mA) got burned out. I am looking out for such dual polarity adaptor in local market. Only single polarity 18V adaptors are available.

Can I get two of them; connect the - of one with + of the other and have this as GRD?

Will the + of the first one become +18V and the - of the second become -18V as required for the speakers ?

 

[Hero999]

Yes you can do that, two laptop supplies connected in series would be your best bet. You'll probably need to add some ferrite beats to the output to get rid of the EMI generated bvy the switching regulator though.

 

[agis68]

The theory of AC is correct. +wave means one direction and - Wave the opposite one.
In DC the minus current (example -9V) represents the ground in most cases.....(once i ve seen a circuit that uses the ground as the positive pole but i think was an anorthodox circuit)
Now combining + and - currnents in DC u obtain different currents (ie +6 + (-3)= +9V) and so on....