Chapter II
Portable digital multimeter
21
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When the scale of the value to be measured is unknown, check that the scale
initially set on the multimeter is the highest possible or, wherever possible, choose
the autoranging mode.
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Before changing functions, disconnect the test leads from the circuit under test.
∗
When performing current measurements, never change of range, do not connect or
disconnect leads without first isolating the current. If you do, there is a risk of
generating surge currents which can blow the fuses or damage the instrument.
∗
In TV repair work, or when carrying out measurements on power switching circuits,
remember that high amplitude voltage pulses at the test points can damage the
multimeter. Use of an HA 0902 type TV filter will attenuate any such pulses.
∗
Never perform resistance measurements on live circuits.
1.1.3. Symbols
W arning : Refer to the user's m anual.
D a ng e r, h ig h v oltage : R isk of elec tr ic sh oc k
E arth term ina l
1.1.4. Opening the instrument
∗
Before opening the instrument, always disconnect from all sources of electric
current and make sure not to be loaded with static electricity, which may destroy
internal components.
∗
Fuses must be replaced with fuses of the same rating and type.
∗
Any adjustment, maintenance or repair work carried out on the multimeter while it
is live should be carried out only by appropriately qualified personnel, after
having taken into account the instructions in this present manual. A "qualified
person" is one who is familiar with the installation, construction and operation of
the equipment and the hazards involved. He is trained and authorized to
energize, de-energize circuits and equipment in accordance with established
practices.
∗
When the instrument is open, for maintenance purposes for example, remember
that some internal capacitors can retain a dangerous potential even after the
instrument is powered down.
∗
If any faults or abnormalities are observed, take the instrument out of service and
ensure that it cannot be used until it has been checked out.
∗
It is recommended to remove the battery from the instrument if not used.
