3 - DC AND AC VOLTAGES
I Connect the leads to the multimeter and connect in parallel to the
circuit to be tested.
I When the order of magnitude is not known, place the switch on the
highest range then progressively lower to the appropriate range.
I To get the voltage in V, multiply the value read on the appropriate
scale by the reading coefficient shown in the table.
V DC
(1)
100 mV
1 V
Scale
100
100
Reading
x1
(2)
x0,01
coefficient
Internal
2 kΩ
20 kΩ
63,2 kΩ 200 kΩ 632 kΩ
resistance
(3)
Accuracy
(4)
2,5 %
Permitted
440 V
overload
(1) Common to the 50 µA range
(3) Specific R: 20 kΩ/V, except range 1000 V-R = 6.32 kΩ/V
(4) In % of the end of scale
~
V
10 V
30 V
Scale
100
30
Reading
x0,1
x1
coefficient
Internal
63,2 kΩ 200 kΩ 632 kΩ
resistance
(3)
Accuracy
(4)
3 %
(3)
Bandwidth
100 kHz 50 kHz 25 kHz
Permitted
440 V
overload
4 - DECIBELS
I Reminder. The measurement of an AC voltage can be expressed
in decibels (symbol dB). The decibel is the ratio of two quantities or
levels. Level N, in dB, of a voltage U has the mathematical expression:
N dB)
(
U
is the reference voltage of 0.775 V AC for a power P
o
a load of 600 Ω.
I Use. Zero level of the red scale in dB corresponds to U
the 10 V AC range. The reading is direct in dB for the 10 V AC range
from 0 to +22 dB. For the other ranges, it is possible to read in dB (near
value) by adding respectively:
+10dB on the 30 V AC range
+30dB on the 300 V AC range
3 V
10 V
30 V
100 V 300 V 1000 V
30
100
30
100
x0,1
x0,1
x1
x1
2 MΩ 6,32 MΩ 6,32 MΩ
1,5 %
1000 V
(5)
(2) Direct reading in mV
(5) For 15 seconds
100 V
300 V
1000 V
100
30
100
(1) Specific R:
x1
x10
x10
(2) In % of
2 MΩ 6,32 MΩ
2,5 %
(3) From 20 Hz to ...
1 kHz
(4) For 15 seconds
(5)
(5)
1000 V
1500 V
(
)
= 20
log
U U
10
0
+20dB on the 100 V AC range
+40dB on the 1000 V AC range
30
100
x10
x10
1500 V
(5)
6.32 kΩ/V
the end of scale
of 1 mW on
o
= 0.775 for
o
13