Bill Orr's Voltage Doubler R Factor Graph
The text below the figure reads
The full load d-c voltage of an IVS-rated voltage-doubler power
supply may be determined with the aid of this graph.
The secondary resistance of the transfomer is measured and
the R' factor is found.
For example, a transformer having a secondary resistance of
20 ohms has an R' factor of about 40. The factor is used in
formula 7 to calculate the full load d-c voltage of the
Eload = Enoload - R' x ( I x R)
Where R' is determined from figure 18
I is the full load current in Amperes
R is the secondary resistnace of the transformer