Details
ResourceFunction["NthDigit"][x,n] returns the nth most significant digit of x when expressed in standard positional form, padding with zeros to the right of the decimal if necessary.
For numbers x<1, ResourceFunction["NthDigit"][x,1] gives 0 and ResourceFunction["NthDigit"][x,n] gives the digit n-1 places to the right of the decimal point.
The base b in ResourceFunction["NthDigit"][x,n,b] need not be an integer. For any real b such that b > 1, ResourceFunction["NthDigit"][x,n,b] finds the largest integer multiples of bn that can be subtracted from x while leaving a non-negative remainder.
ResourceFunction["NthDigit"][x,n,b] discards the sign of b.