Use
the Touch Hold mode (see
item
10)
to make audible diode
tests. When the
test leads
are
placed
across
the diode,
a
good
diode
or
transistor junction
will
cause the
meter
to beep
(and
update the
display) in
the
forward-biased direction and remain
silent
in the
reverse-
biased direction. A short
or
resistance
below about 4000 ohms
will
causea
beep in
both
directions. If
an open
is
detected,
the meter
will
remain
silent
in
both
directions.
Using
the
Analog
Display
The
analog
display is easy to
use
and interpret
It
functions
much
the
same
as the
needle
on
an analog meter without
the
mechanical
overshoot
inherent in needle movements.
The analog display is especially useful for
peaking
and
nulling,
and
observing
rapidly changing inputs. The analog display
response time is fast, and
it
can
be used
to
make
approximate
adjustments quickly. The 4000-count
digital display
can then
be used
for final adjustment.
The analog display can also be used for
limited diagnostic
purposes. In situations where rapidly fluctuating signal levels
make
the
digital display useless, the
analog
display
is ideal.
Like the
needle
on a
Volt-ohm-milliammeter (VOM),
the
analog
display excels at
displaying trends, or slowly changing signals.
Many
diagnostic routines using
the
analog
display require
practice. You
will usually
be
looking for
good or bad
signal
APPLICATIONS
Using the
MIN
MAX Recording
Mode
patterns
that occur over
some span of time. Noisy resistance
measurements, for instance, create
such
patterns. Therefore,
familiarity with analog display
response and movement is
necessary to
accurately
interpret
a
signal
pattern. Compare
the
analog display response when
making
measurements
on
a unit known
to
be
good, to the analog display response when
making
measurements
on
a
faulty unit
Using
the MIN MAX Recording
Mode
The
MIN
MAX Recording mode can be
used to
catch inter-
mittents and turn
on
or turn off surges, verify performance,
measure while
you
are away ("baby sit"),
or
take readings
while
you are
operating
the
equipment
under test
and cannot
watch
the meter. The audible
Min
Max Alert indicates when
a
new minimum
or maximum value
has
been
recorded.
You
can
select either
a
100 millisecond, 1 millisecond (Peak),
or
1 second
(high
accuracy) "response
time"
for
recording
minimum and
maximum
readings. The response time is the
length of
time
an
input must stay at
a
new value to record the
full
change.
The
100
millisecond
response time
is
best for
recording power
supply surges, inrush
currents,
and
finding
intermittent fail-
ures. This mode follows the update time
of the
analog
display.
(The
minimum and maximum excursions
of
the
analog
display
get recorded.)
23
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