Axis

Sound level

neperNp

The natural-logarithm ratio unit; 1 Np = ln(e) in field quantities.

Dimension
1
Canonical signature
1
System
si accepted
Exactness
Exact by definition

Definition record

How this unit is defined

Canonical base
This unit defines its own base.
Conversion type
log
Historical notes
For power-like quantities 1 Np ≈ 8.6859 dB.
Aliases
nepers, nepers ratio

Same dimension

Related units

percentcommon%decibelsi accepteddBparts per millioncommonppmMach numbercommonMaparts per billioncommonppbspecific gravitycommonSGparts per trillioncommonpptexposure valuecommonEV

Common conversions

Every conversion routes through the canonical base of the dimension.

This unit defines its own dimension.