Let X be the value observed on the oscilloscope (unit: V).
X × 10 (20dB) × 10 (20dB) ÷ 2 (2Ω resistance of the target) = peak current value (unit: A).
Example: If the oscilloscope displays 0.15V when 2kV is applied
(The standard specifies 7.5A ±15% at 2kV.) 0.15V × 10 × 10 ÷ 2 = 7.5A