Hi,

If DC is applied to a capacitor , can the Xc formula also apply, minus the " frequency " component ..??

Xc = 1 /(2*pi*f*C ) , remove f , becomes ; Xc = 1 /(2*pi*C ) ,

for DC , presenting an open circuit at maximum Ohms .
Ive calculated some μF measurements and they come out ,way into the MegOhm range ,so is it normal to utilise this idea ?.

 

The frequency still applies, and it is zero.

and, No, it is not normal to utilize faulty formulas.

 

In DC, you suppose the frequency to tend towards 0. Knowing that,
\(X_C = \frac{1}{2\pi f C} |_{f\rightarrow 0} = \infty\)
That's why in a DC analysis, you can pretend that capacitors are open-circuits.