Decibel Measurements - Chauvin Arnoux C.A 406 Notice De Fonctionnement

English
Reading:
To obtain the value of the voltage in V, multiply the reading on the appropriate
scale by the reading coefficient, as shown below.
DC
AC
DC
and
AC
(1)
Position common to the 50µA DC range.
(2)
Position common to the 150µA AC range.
4.2

DECIBEL MEASUREMENTS

Reminders and definitions:
The measurement of an AC voltage can be expressed in decibels (dB). The
decibels are a ratio of two quantities or levels. It is basically used to determine the
output power of amplifiers; normally the output voltage U is measured.
The reference power P
load resistance of 600Ω, thus a reference voltage U
Level N, in dB, of voltage U is expressed mathematically as:
N dB = 20 log
10
28
V ranges
(1)
100mV
1V
3V
(2)
3V
10V
30V
100V
300V
1000V
chosen as zero level in telecommunications is 1mW, with
0
U
U
0
Scales
Direct reading
Black 100
Black 100
Black 30
Red 3
Black 100
Black 30
Black 100
Black 30
Black 100
of 0.755V AC.
0
Reading
coefficient
in mV
X 0.01
X 0.1
X 1
X 0.1
X 1
X 1
X 10
X 10
C.A 406