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Press the V pushbutton to enable the
voltage measurement mode and then
select AC or DC by toggling the AC-
DC pushbutton.
This Meter defaults in the
autoranging mode and displays V,
AC and AUTO. AUTO (autoranging) is
applied to the bar graph.
To measure voltage, connect this
Meter in parallel with the load or
circuit under test. Each of the three
AC/DC voltage ranges presents an
input impedance of approximately 10
MΩ in parallel with less than 100pF.
Measurement errors due to circuit
loading can result when making
either AC or DC voltage measurement
on circuits with high source
impedance.
In most cases, the error is negligible
(0.1% or less) if the measurement
circuit source impedance is 10 kΩ or
less.
5.9 Measuring Resistance
Press the Ω pushbutton to enable the
resistance measurement mode. This
Meter defaults in the autoranging
mode and displays KΩ and AUTO.
And also the off-scale arrow of the
bar graph blinks and the digital
display reads OFL.
AUTO (autoranging) is applied to the
bar graph.
This Meter measures resistance by
comparing the internal reference
resistance given by a resistor array
with the unknown resistance to be
measured.
Remember, the resistance displayed
by this Meter is the total resistance
through all possible paths between
the probes. This explains why in-
circuit measurement of resistors does
not often yield the resistance value
indicated by the resistor’s color code.
CAUTION: TURN OFF POWER ON THE TEST
CIRCUIT AND DISCHARGE ALL CAPACITORS
BEFORE ATTEMPTING IN-CIRCUIT RESISTANCE
MEASUREMENTS. IF AN EXTERNAL VOLTAGE
IS PRESENT ACROSS A COMPONENT, IT WILL
BE IMPOSSIBLE TO TAKE AN ACCURATE
MEASUREMENT OF THE RESISTANCE OF THAT
COMPONENT.
The resistance in the test leads can
diminish accuracy on the lowest (400
Ω) range. The error is usually 0.1 to
0.2 Ω for a standard pair of test leads.
When measuring resistance, be sure
that the contact between the probes
and the circuit under test is good.
Dirt, Oil, Solder flux, or other foreign
matter seriously affect resistance.
5.10 Continuity Testing
