Application Note

2 Fluke Corporation The electronic technician’s Fluke 287 DMM
Bandwidth
Other interesting features include
the 100 kHz bandwidth of the
Fluke 287 DMM, V ac and mV ac
functions, and the ability to read
voltage values expressed as dBV
or dBm. This true-rms reading
function is essential for evaluat-
ing the performance of servo
loops and audio amplifiers.
And, since one of the uses for
dB measurements is testing the
frequency response of amplifiers,
the Fluke 287 DMM designers
included the ability to set up the
instrument to simultaneously
measure dBV or dBm and the
frequency of the measurement
in dual display mode. Add to
this the ability to setup the dBm
mode for a broad range of refer-
ence impedances and the 287
becomes the tool of choice for
amplifier and audio transmission
line performance testing.
Capacitance
Among the new features is
capacitance that now reads up
to 100 mF. With all of today’s
supercaps, and the large capaci-
tors used in electronic motor
drives and power inverters, this
order of magnitude contribution
to range is sure to be popular.
AC + DC true-rms voltage
and current
Volts or amps readings can be
made showing individual ac and
dc values in a dual display, or
the two values may be combined
to display the true-rms signal
present.
The dual display mode is
useful for evaluating dc power
supplies and any present ripple
voltage. This mode also sup-
ports troubleshooting triac-based
power controllers where both
ac and dc values are present.
AC+DC true-rms allows evalua-
tion of the heating effect of the
combined values. You can also
revert to a standard dc measure-
ment where you can then evalu-
ate duty cycle and pulse widths
of these complex waveforms in
the dual display mode.
Temperature
The mV dc menu offers the abil-
ity to convert the meter to a
thermometer in either degrees
Fahrenheit or Celsius, based on
the output of a K-type thermo-
couple. In this mode, the meter
monitors the temperature of the
input jacks to provide the refer-
ence value needed for accurate
measurement. And, using the
recording function to log tem-
perature over time means the
test technician can evaluate
electronic system cooling over
a wide range of conditions for a
day or more.
Basics
This new meter excels in the
basics too, beginning with its
50,000 count resolution. Take for
example, its 50 mV range where
you can read voltages down to
1 μV. Basic dc accuracy is 0.025
%, while basic true-rms ac read-
ings are accurate to 0.3 %. And
remember, ac measurements can
be made over a broad frequency
range—up to 100 kHz.
All in all, the new Fluke 287
is yet another example of how
suggestions by busy technicians
can be integrated into a powerful
and still easy to use tool.
Fluke Corporation
PO Box 9090, Everett, WA USA 98206
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
For more information call:
In the U.S.A. [phone] or
Fax [phone]
In Europe/M-East/Africa [phone] or
Fax [phone]
In Canada (800)-36-FLUKE or
Fax [phone]
From other countries [phone] or
Fax [phone]
Web access: http://www.fluke.com
©2007 Fluke Corporation. Specifications subject
to change without notice. Printed in U.S.A.
11/2007 3182854 A-EN-N Rev A
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