The equation of a circle is given by \( x^{2}+y^{2}=a^{2} \), where \( a \) is the radius. If the equation is modified to change the origin other than \( (0,0) \), then find out the correct dimensions of \( A \) and \( B \) in a new equation: \( (x-At)^{2}+\left(y-\dfrac{t}{B}\right)^{2}=a^{2} \). The dimension of \( t \) \( [T^{-1}] \).