3-2 AC VOLTAGE
V AC
5V 15V 50V 150V 500V 1500V
Range
(indication)
5 V
AC
(f) 15 (a) 50 (b) 15 (a) 50 (b) 15 (a)
Reading
coefficient
x 1 x 1 x 1 x 10 x 10 x 100
Internal
resistance
(1)
31.6kΩ 94.8kΩ 316kΩ 948kΩ 3.16MΩ 9.48MΩ
Accuracy (2)
2.5%
Bandwidth
16Hz to 1kHz
16Hz to
500Hz
Admissible
overload
320V (3)
440V (4)
500V 1500V
(1) specific R: 6.32kΩ/V
(2) in % of end of range
(3) for 1 minute
(4) for 20 seconds
The presence of a DC component falsifies the measurement.
3-2-1 DECIBELS
■ Reminder: measurement of AC voltage may be expressed in decibels
(dB). A decibel is the ratio between two measurements or levels. Level N in
dB for U voltage is mathematically expressed as:
N (dB) = 20log
10
(U/U
0
)
U
0
is reference voltage 0.775V for P
0
power of 1mW for a load of 600Ω.
■ Use: The zero level on the red range in dB corresponds to U
0
= 0.775V for
calibre of 5V . Readings are given in dB directly for the calibre
5V (from -6 to +22dB). For the other calibres, it is possible to read in dB
(approximate value) by adding respectively:
Calibre 5 V
AC
15 V
AC
50V
AC
150 V
AC
500 V
AC
1500 V
AC
Reading G
in dB
Direct
reading
A = G
A =
G + 10dB
A =
G + 20dB
A =
G + 30dB
A =
G + 40dB
A =
G + 50dB
3-3 DC AND AC INTENSITIES
Always cut the power supply on the circuit to be controlled before connecting
the multimeter to the circuit. If the "Fus" LED is on, change the faulty fuse(s).
(Reminder: minimum voltage for LED = 110V).
Connect the leads to the multimeter and connect in series in the circuit with:
- The red lead in terminal "A", up to 1.5A.
- The red lead in the "10A" terminal for 10A
DC
and
AC
calibre.
Cut power supply before switching.
13
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