According to wikipedia the only SI fundamental unit for Matters Electrickal is the ampere. Don't you at least need the ohm to derive anything? How would you make volts from only amps?
Perhaps I misunderstand the meaning of "fundamental unit".
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Volt is defined as Work done for unit charge. Charge can be derived from product of current and time. So volt can be expressed in terms of mass, distance, time and current.
Now for ohms, it can be defined as the ratio of voltage and current. So it can also be expressed in terms of mass, distance, time and current.
So with just a unit for current combined with other fundamental quantities, we can define all the other electrical quantities.
The Ampere is actually not a fundamental unit. It is Coulombs/second, with Coulombs and seconds being the fundamental units. Other common electrical units can be derived from the non-electrical fundamental units and the Coulomb. For example, a Volt is a Joule/Coulomb, or expressed in fundamental units is a Netwon-meter/Coulomb. A Ohm is a Newton-meter-second / Coulomb^2. You can continue on and derive Farads, Henries, etc, similarly.
I noticed that I used Netwons above, which is also not a fundamental unit. A Newton is a Kg-m/s^2. A Volt expressed in terms of fundamental units (Kilogram, meter, second, and Coulomb) is therefore Kg-meter^2/second^2-Coulomb.
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