Prior to using the Fluke Digital
Multimteres I used the cheap ones, like from Radio
Shack. They say "to error is human" and when you error
with a DMM it's usually something like forgetting to
change from Ohms to AC volts and then sticking the probes into
the A.C. mains outlet. The next thing is you get to
watch and smell the smoke coming out of the meter.
Sometimes the destructive energy is not great enough to let
the smoke out and you just get wrong readings.
The cure for that is to use the Fluke (or other high end) DMMs
that are designed to withstand that kind of abuse. This is my
second model 87.
I wore out the switch on my first model 87 (I don't think they
had the lifetime warranty then.) and sometimes it does not
turn off and so drains the battery.
Over the years I've used many many multimeters. One was
in EICO kit ik Ohm/V analog meter and got me on San Fransisco
channel 9 for building it.
Another was the Heathkit VTVM I still have, but the plastic
analog meter bezel was broken.
There are times when one is a better choice than
another. When troubleshooting something like a lawn
sprinkler system the Fluke 12 or a very cheap analog
multimeter (1k Ohm/volt) works much better than the Fluke 87
or a VTVM because the cheap meter (or Fluke 12) presents a
load when measuring voltage and so a break in the wire shows
up. But if you use the Fluke 87 (hi-Z input) you see the
supply voltage because there's no load to pull it down.
The Fluke 12 has an internal resistor shunting the Voltage
input in the VCheck mode for just this reason.
I haven't tried it but suspect that the Max/Min/Average
function on a Fluke 87 DMM could be used on telephone
dials to good effect.
I spent a few decades working with semiconductors and the Vf
measurement, when done at 1.0 ma, is a very useful thing to
know about a diode. The Fluke 87 uses a 1.0 ma current
source for the diode function, but other meters may simply use
a resistor (not a current supply) and so the Vf value is not
Note by measuring a transistor with the diode function with
both polarities (E-B, B-E, C-B, B-C) you should see two
forward diodes and something approaching an open circuit on a
good transistor that's not connected to anything else.
This can be used to identify which wire is which and tell if
it's an NPN or PNP. But there are transistor testers
that do a
much better job and some work while the transistor in
installed in a circuit.
Another thing that's nice about the Fluke 87 is that he AC
measurements are true RMS rather than displaying an RMS value
based on using peak detection of the waveform. The
latter method works if the signal is a pure sinewave, but is
in error for other waveforms.
I tried to measure the short current output (Flash Amps) of
some No. 6 1.5 Volt batteries
with the Fluke 87, but the current was so high it blew out the
internal protection fuse
. Those fuses are
pricey. When No. 6 batteries were popular there were
pocket analog current meters (not voltmeters) that were used
to check the "flash amps".
4335349 Simulated ohms
generation method and apparatus for calibrating resistance ...
4389708 Method and apparatus for enhancing the output of an
RMS converter -
D280299 Digital multimeter for electrical measurement - 10
D281864 Electronic instrument meter cover -
D337435 Multimeter holster
D446735 Digital multimeter
D295148 Digital multimeter accessory
4841229 Method of and circuit for ohmmeter calibration
4847507 Fiber optic guard crossing of circuits having analog
and digital sections
4860289 Reset circuit for electrically isolated circuits
communicating via uart
4864512 Measurement apparatus with plural displays of measured
parameter and ...
4940204 Instrument having flexible stand
4947355 Modular electronic instrument system having automated
5012181 Apparatus for and method of internally calibrating an
D314715 Digital multimeter
5073757 Apparatus for and method of measuring capacitance of a
5122627 Asymmetrical electrical switch actuator
5142221 Automatic function selecting multimeter
5146390 LCD support bracket
5218290 Multi-function, multi-mode switch for an instrument
5186634 Electrical contact having spring-biased tabs for
mounting to a circuit board
5227984 Instrument with continuity capture feature
5379176 Protective input circuit for an instrument
5418450 Coupling circuit for a measuring instrument
5432706 Multimeter having min/max time stamp
D359006 Digital clamp meter
5508607 Electronic test instrument for component test
5512841 Peak current detection in a test instrument for
ensuring validity of ...
D369306 Graphic multimeter instrument
5530373 Method and apparatus for determining and selectively
displaying valid Measurement Information
5594329 Method and apparatus for obtaining voltage-isolated
measurement channels ...
5691635 Probe identification system for a measurement
5698984 Adaptive digital filter for improved measurement
accuracy in an electronic ...
5705936 Method and apparatus for automatically testing
5839633 Multimeter belt holster
5920188 Voltage measurement instrument having transient
overvoltage input protection
5930745 Front-end architecture for a measurement instrument
6043640 Multimeter with current sensor
Input ranging circuit for an electronic instrument, (Fluke),
Jul 25, 2000, 324/158.1; 324/115; 324/731 -
6094949 Lock device for electronic test apparatus
6163445 Low-voltage test signal path protection circuit with
extended bandwidth ...
6191723 Fast capacitance measurement
6201320 Automatic power turn-on circuit for a battery-powered
voltage measurement ...
Capacitance measurement, (Fluke), Aug 14, 2001, 324/678;
6281673 Low error, switchable measurement lead detect circuit
6318687 Accessory mount
6392402 High crest factor rms measurement method
6466003 Microamp measurement for two-terminal digital meter
6469492 Precision RMS measurement
Capacitance measurement, (Fluke), Sep 23, 2003, 324/678;
324/658; 324/677 -
6628113 Surge current measurement
7242173 Combined test instrument probe and voltage detector
7342393 Multimeter with filtered measurement mode
D562317 Digital multimeter case