Using The Multimeter; Preparing For Measurement; Measuring Voltage; Measuring Resistance - Tektronix TEKTOOLS DMM155 Instructions Manual

Using the Multimeter
Please read this section to learn how to use your
DMM155 or DMM157 Digital Multimeter safely and
efficiently.
Preparing for Measurement
1. Wait 30 seconds after turning on the meter before
making a measurement.
2. Set the rotary switch to the function you want to use
before connecting the probes to voltage or current.
Disconnect the test leads from the voltage or current
before selecting a new function.
3. Disconnect power to the equipment under test if you
are measuring resistance or capacitance, testing
continuity, or checking diodes.
4. If you use the multimeter near equipment that
generates electromagnetic interference, the display
may be unstable or indicate incorrect measurement
values.
Measuring Voltage
A WARNING. Do not apply more than 600 VDC or 600
LAVACRms to the input. Do not apply more than
600 VDC or 600 VACRms between the COM input
terminal and earth ground. Exceeding these limits
creates a shock hazard to the user and can also
damage the meter.
Use extreme caution to avoid personal contact with
high voltage when measuring in high voltage circuits.
1. Connect the black test lead to the COM (—) terminal
and the red test lead to the VD (+) terminal.
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2 Set the rotary switch to the V function.
3 Press the AC/DC button to select AC or DC
measurement. (The display indicates AC but not DC.)
4 Connect the test leads across the source or load. The
multimeter automatically selects the range and
displays the polarity and voltage. Input voltage that
exceeds the selected range causes the
most-significant digit ("1" or '-1") to flash.
Measuring Resistance
I. Connect the black test lead to the COM terminal and
the red test lead to the vn terminal.
2. Set the rotary switch to the Q position to measure
resistance up to 2 MO; set it to the 2-20 MD position
to measure resistance from 2 MO to 20 MO.
A WARNING. To prevent possible personal injury or
Udamage to the meter, make sure the device being
tested is off and no source of voltage is present.
3. To measure in-circuit resistance shunted by
semiconductor junctions, press the D/LPD switch for
lower power resistance measurements. The display
indicates "LPO".
4. Connect the test leads across the resistance. For the •
best accuracy when measuring low resistance, short
the test leads together and press RANGE: then press
the OFFSET button. This selects the lowest range and
compensates it for the resistance of the test leads.
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