3B U17451 Інструкція з експлуатації - Сторінка 5

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3.6 Attenuation and gain

measurement

COM

AΩ

• In communications engineering

the gain or attenuation of a signal

is specified in decibels as the log-

arithm of the ratio between the

measured voltage and a defined

reference voltage. Positive values

correspond to a gain and negative

values reflect attenuation. The ref-

erence voltage of the multimeter

amounts to 0.775 V (= 1 mW at

600 Ω). With this voltage there is

a gain of 0 dB.

• Using the rotary switch (1) select

the corresponding measurement

range "600,..., 10 V AC".

• Connect the multimeter and take

a reading on the dB scale.

• Since this scale is only valid for the

10 V measurement range, in the

other measurement ranges a rela-

tive constant must be added to the

value obtained from the scale:

Meas. range

Constants

30 V

10 dB

100 V

20 dB

300 VB

30 dB

600 V

36 dB

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com • Technical amendments are possible

4 Maintenance

4.1 Cleaning

• Only use a paintbrush or soft tow-

el to clean the multimeter. If stat-

ic electrical charging occurs on the

view window this can be eliminat-

ed using a damp rag or an anti-

static agent.

4.2 Battery

• Test the battery from time to time.

If it is dead or it has started to de-

compose, it must be removed from

the device. The battery is replaced

in accordance with 3.1.

• If the multimeter remains idle

over a long period of time, the

battery should be removed from

the unit.

4.3 Replacing the fuse

• The multimeter is equipped with

a safety fuse F3,15 A/500 V. To re-

place the fuse the device must be

opened as described in section 3.1.

Remove the fuse and replace it

with a fuse of identical type. Then

replace the section of housing and

snap it back into place securely.