DID TEURS

self of this added protection. A
recent graphic demonstration
from a skeptical friend pointed
this out. He watched in helpless
horror as a glass of iced tea,
liberally laced with sugar, dispatched
his three-month-old
DMM to silicon heaven.
Beckman enhances the reli ­
ability of the 3010 further by giv·
ing each meter a 100% burn-in,
followed by a complete test of
each function and every range.
All of this results in a digital
multimeter that is trouble-free
and backed by a one-year warranty
under which Beckman
agrees that:
/I the instrum ent fa ils for any
reason whatsoever, except
abuse, Beckman wi/{ (at its election)
repair or rep lace the multimeter
with a new or reconditioned
unit of equivalent quality.
That sounds too good. service
mu st take forever !
Wrong . There is only one word
that can describe Beckman's
service: phenomenal! You will
get no excuses or Interminable
delays when you have an ailing
meter. Instead, Within one working
day from the receipt o f the
meter at a service center, a new
or recond itioned unit will be air
shipped to you,
The 3010 certainly seems well
built. Yet, that price still scares
me a little.
Your reservat ions will fade
after getting to know some of
the 3010'5 features better. The
same custom CMOS chip that
helps make the 3010 so tough
also contributes other useful
traits. The CMOS construc tion
in conjunction with the lowpower
LCD display ensures a
long battery nte. A s-vou alkaline
battery supplies 2000 hours of
continuous operation, Under
normal operating conditions
you can expect two years of service
from a single battery. Tha t' s
ten times longer than other
hand-held 3'h-digit meters provide.
Couple this longevity with
a low-battery warning that sig·
nals for the last 200 hours of
operation and you have erased
any excuse for a dead battery.
This low power drain also frees
the user from external power
sources, adapters, and chargers
which add unnecessary weight.
The 3010 weighs in at a modest
16 ounces.
In the world of micro-electronics,
where minute voltages and
infinitesimal currents are precariously
balanced, outside disturbance
from low-impedance
sources can be disastrous. The
3010's high input impedance of
22 megohms babies delicate circuitry
with less than half the
loading of the conventional
DMM's 1D-megohm impedance,
In fact, this meter's load factor
is far lower than most VOMs.
A baby around delicate equipment,
the 3010 does not play
nursery games when It comes to
life's crueler rea lities-destructive
overloads. The meter will
tolerate transgression as high
as 1500 V dCl1000 V rms on the
voltage inputs, and the resistance
area is protected to 300 V
dcfrms. Both can ward off evil
transients up to 6000 volts in
size. The 2-A current range is
fused against overloads, but the
1D-A range is vulnerable. Making
use of an internal, 0.001'()hm resistor,
this 10-A function Is totally
defenseless, lacking the most
pa ltry of fuses. A glaring omission
on Beckman's part? In a
way, yes, because this does
open the door to operator
abuse, On the other hand, by be­
Ing aware of the potential
danger and by observing a
JO.second t ime lim it, one can extend
the upper current boundary
to 20 Amps. I have successfully
made measurements in excess
of 17 Amperes with no ill effects.
However, I cannot stress stronp­
Iy enough the need to strictly
adhere to the JO.second limitation!
Another feature worth mentioning
is the ln-circult dlodel
transistor test function. One
aspect of the 301 0 is that eu the
resistance ranges are lo w powered,
and as such cannot forward-bias
a semiconductor.
This necessitates that a separate
test function be added to the
meter. As usual, Beckman goes
first class by employing a dedicated
constant-current source,
which, when in operation,
shows the actual voltage
dropped across a semrconductor
Junction, eliminating all
guess work. The test, it performed
in-circu it with a parallel
resistance greater than 200
Ohm s, is completely transparent.
1 like all of the 3010's line
features, but my favorite is
tnste-cnms, Beckman's fast,
versatile continuity indic ator. At
the moment of continuity detection,
an Ohm symbol is displayed
in the upper lett-hand
corner of the LCD display. With
its virtually instantaneous operation,
inete-cnme has created a
wea lth of tests never before
feasible on a purely digital multimeter,
Including those with
audible indicators, Prompt detection
(less than 100 milliseconds)
allows the 3010 to accomplish
analog-style tests
such as checking a cacecrtcr's
ability to accept and hold a
charge. In this case, the analog
needle is repl aced by the rnste­
Ohm s symbol, which appears
quickly as the test begins. The
charging capacitor's apparent
resistance falls within twice the
maximum of the selected range.
A readout of the resistance
follows almost immediately.
The cap's steadily building
ctlarge SWi ngs the reading upward
toward infinity, until a
point is reached where one of
two things will happen. Depend·
ing on the selected resistance
range, either the readout and
lnsta-Onms will overflo w, or a
final breakdown value for the
capacitor will be found. The
necessity for fast electronics in
this test becomes obvious when
you involve small value caps
with their short time constants.
The rnete-ohms speed is such
that I have had no problem
Checking 2.2-uF and smaller tantalums.
tnsta-Onms has several irnportant
adva ntages over ohmmeters
and aud ible continuity
indicators. First, with the overload
protection of 300 V dC/rms,
you don't have to worry about a
damaged meter movement or
bent and broken needles. Second,
as part 01 the liquid-crystal
display, the indicator uses little
power, contributing greatly to
the meter's two-year battery life,
Finally, because it isn 't limited
to one or two resistance ranges,
fnsta-Ohms is useful in tracking
down high-impedance " short s."
You also have the blessing o f
not having to use an overri de
switch on large jobs to kill the incessant
buzz that drives fellow
workers up the wall.
I'm impressed . I think I'll
spend the extra bucks.
In that case, you should be
glad to hear that the 3010comes
ready to use, having a battery,
spare fuse, safety test leads,
and operator manual. Beckman's
attention to detail and quality
carries into their excellent accessories.
The awkward-looking
test probes are actually comtortable
to use. So much so that I
never gave them much thought.
Nonetheless, they exerted an influence
on me, however subt le.
This influence became evident
when I had the occasion to use a
reqular pair of test leads on a
240-volt power supply. I was
distinctly apprehensive at the
t ime, and the reason why eluded
me. I now know the reason: Subccnscicusiy.t
missed the added
security imparted by the knobby
node end of Beckman's safety
test leads.
This brings us 10 the 3010's
operator manual. It is one of the
best I've seen. Unlike the scant,
inept papers some manufacturers
try to pawn off as manuals,
the Beckman manual is an indepth,
comprehensive guide to
the understanding and use of
the 3010. Although faulted as
being too long, a premise I do
not share, the manual is worth
the read ing effort.
OK, OK, I'm convinced. Well,
almost. There has got to be a
zinger-you haven't mentioned
one bad word about the meter!
Zinger? I don't know if you
could classify them as such, but
there are a couple of items that
I'm a little less than thrilled
about. One, and the brunt of my
dissatisfaction must fall upon it,
is the 3010's built-in tnt-can.
Conceived as a dual-purpose
hangerlbench support, the wire
bail is all too flimsy for hanging
the meter. Its most unforgivable
sin o f sins is the metal construetion
which makes it a great conductor
and, thus, dangerous.
The only other fault with the
3010 is that you cannot zero
the resistance fu nction. This
becomes a factor only when using
the lowest range, and the
resistance of the test probes is
displayed. Less than 0.2 of an
Ohm in value, my objection cen ­
ters on the fact that no means of
zeroing th is reading is provided.
You've made a sale! I can contend
with those easily.
Fine- my sentiment exactly.
If you wan t to hunt exotic nonsinusoida
l waveforms like triangles
and ramps, look into
Beckman's AMS 303O-current­
Iy the only hand-held DMM wilh
true-rms measurement capability.
For more information, contact
Advanced Electro-Products
Division, Beckman Instruments,
toe; 2500 Harbor Blvd., Fullerton
CA 82634; (714)-871-4848,
ext. 3651. Reader Service number
476.
John Clawson
Tillamook OR
73 Magazine . April, 1981 127