Ohm's Law: E = I x R

  E          E = I x R
----- = 1    I = E / R
I x R        R = E / I

  P          P = I x E
----- = 1    I = P / E 
I x E        E = P / I

             P = I^2 x R
	     P = E^2 / R


Resistance In Series:
Rt = R1 + R2 + R3 + ...

Resistance In Parallel:
             1
Rt = ------------------
      1    1    1
      -- + -- + -- + ...
      R1   R2   R3