Sanwa U-50D Operator's Manual page 29

Example 1. Providing the meter reads 9dB for the
AC 2.5 volt range for a speaker impedance
of 16 ohms, the Load Impedance [Q) 16 is
followed up, and then to the left at the
intersecting point with the oblique line
to obtain 15.7 on the Decibel Additon
axis.
24.7 is the decibel value to be taken for
comparison.
Example 2. Providing the primary of an output
transformer of 5k - ohm impedance is
checked on AC 50 volt range and the
meter reads 20.2dB on the scale for AC
10 volt reading, it is 20.2
for the 50 volt reading.
Load Impedance k.Q is followed down,
and then to the left at the intersecting
point with the oblique line to obtain 9.2
on the Decibel Addition axis.
25 is the decibel value to be taken for
9 ; 15.7 24.7
34.2 — 9.2 = 25
— 27 —
14 34.2 dB
Now 5 of the