Instructions

19
■ When the order of magnitude is not known, place the switch on the
highest range then progressively lower to the appropriate range.
■ Analogue reading: to get the current in mA, mA or A, multiply the
reading on the appropriate scale by the reading coefficient shown
in the table.
■ Digital reading: if necessary, press the following keys
6 - DC AND AC CURRENTS
Always switch off the circuit to test before connecting the
multimeter to the circuit. If the “Fus.” light comes on, change the
faulty fuse(s) (Reminder: minimum voltage of 100 V).
Connect the leads to the multimeter and connect in series to the
circuit with:
- the red lead in the "µmA", terminal, up to 1 A
- the red lead in the "10 A", terminal, from 1A to 10 A
- for the rms value (See in Ch.3)
- MAX for the maximum value
- HOLD to hold in memory
- for display backlighting
5 - DECIBELS
■ 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:
U
0
is the reference voltage of 0.775 V AC for a power P
0
of 1 mΩ on
a load of 600Ω.
■ Use. Zero level of the red scale in dB corresponds to U
0
= 0.775 for
the 4V AC range. The reading is direct in dB for the 5 V AC range, on
analogue only, from -20 to +16dB.
The digital display indicates the value of the voltage in volts.
For the other analogue ranges:
● 500mV : subtract -20dB
● 50V : add +20dB
● 500V : add +40dB
● 1000V : unusable
(
)
N dB) U U( log= 20
10 0
~