Jaycar QM1571 User manual

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QM1571 OPERATING INSTRUCTIONS
TRUE RMS AUTORANGING DIGITAL MULTIMETER

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SAFETY WARNINGS
The following safety information must be observed to insure
maximum personal safety during the operation at this meter:
♦Measurements beyond the maximum selected
range must not be attempted.
♦Extreme care must be taken when measuring above
30 VAC or 60VDC, especially on live bus-bars.
♦To measure voltage, the instrument must not be
switched to a current or resistance range, or to the
diode check or buzzer position.
♦Circuits must be de-energised and isolated before
carrying out resistance tests.
♦The rotary function switch must only be turned after
removing test connections.
♦All external voltages must be disconnected from
the instrument before removing the battery.
♦Test leads and probes must be in good order, clean,
and with no broken or cracked insulation.
♦ UK Safety Authorities recommend the use of fused
test leads when measuring high energy systems.
♦Replacement fuses must be of the correct type
and rating.
♦The instrument must not be used if any part of it is
damaged.

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♦Warnings and precautions must be read and
understood before the instrument is used. They
must always be observed during the operation of
this instrument.
Symbols used on this instrument are:
Caution: refer to accompanying
notes
This symbol indicates that the operator
must refer to an explanation in the
Operating Instructions to avoid personal
injury or damage to the meter.
Caution: risk of electric shock
This WARNING symbol indicates a
potentially hazardous situation, which if
not avoided, could result in death or
serious injury.
This CAUTION symbol indicates a
potentially hazardous situation, which if
not avoided, may result in damage to
the product.

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This symbol advises the user that the
terminal(s) so marked must not be
connected to a circuit which the voltage
with respect to earth or ground exceeds
(in this case) 1000 VAC or VDC.
Equipment protected throughout by
Double Insulation (Class III).
Equipment complies with current EU
directives.
SYMBOLS AND ANNUNCIATORS
Continuity
Low Battery
Wireless transmit mode
Diode test
HOLD Data Hold
AUTO Auto Ranging
AC Alternating Current or Voltage

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DC Direct Current or Voltage
V Volts
A, mA, µ A Amps, milli-Amps, micro-Amps
OPERATION
To turn on the meter rotate the function switch from the
OFF position to any measurement position.
For best battery life, ALWAYS turn the function switch to
the OFF position when the meter is not in use. This
meter has an Auto OFF capability that automatically
shuts the meter OFF after 30 minutes.
NOTE: On some low AC and DC voltage ranges, with
the test leads not connected, the display may show a
random, changing reading. This is normal and is caused
by the high-input impedance and the input sensitivity.
The reading will stabilize when connected to a circuit.
MODE button
Selects AC or DC measurement when in Voltage or
Current modes, also selects resistance, diode, continuity
or capacitance modes and °C or °F display modes.

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HOLD/BACKLIGHT button
The HOLD button holds the current display reading until
momentarily pressed again. Press and hold this button
for more than 2 seconds to turn the backlight on. Press
again for more than 2 seconds to turn off the backlight.
RANGE button
When the function switch is operated, the meter
automatically starts operating in Auto Ranging mode.
This selects the best range for the measurement being
made and is generally the best mode for most manual
measurements. For data logging measurements or when
required, the range may be manually selected, as
follows:
1. Press the RANGE button. The "AUTO" indicator on
the display will turn off.
2. Press the RANGE button to step through the
available ranges until the required range is selected.
3. Press and hold the RANGE button for more than 2
seconds to revert back to "AUTO" operation.

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REL button
The REL button performs a relative measurement.
Except for Hz, %, Diode and Continuity, all other
functions will operate in the relative mode.
Hz% button
Hz% is the Frequency/Duty Cycle select button. In the
frequency measurement mode (function switch set to
Hz%), pressing the button can select frequency or duty
cycle measurements; in AC/DC Voltage or Current
modes, pressing the key will switch to Frequency/Duty
Cycle measurement mode and then back to voltage or
current mode.
DC/AC VOLTAGE MEASUREMENT
1) Insert the black test lead into the negative COM jack
and the red test lead into the positive Vjack.
2) Set the function switch to the Voltage Vposition.
3) Use the MODE button to select AC or DC Voltage.
4) Connect the test leads to two points in the circuit to
measure the voltage difference.
5) Read the voltage measurement on the display.

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DC CURRENT MEASUREMENT
1) Insert the black test lead into the negative COM jack.
2) For current measurements up to 4000 µ A DC, set the
function switch to the µ Aposition and insert the red
test lead banana plug into the µ Ajack.
3) For current measurements up to 400mA DC, set the
function switch to the mA position and insert the red
test lead banana plug into the mA jack.
4) For current measurements up to 10A DC, set the
function switch to the 10A position and insert the red
test lead banana plug into the 10A jack.
5) Use the MODE button to select AC or DC Current.
"DC" must appear on the display.
6) Remove power from the circuit under test, then open
the point in the circuit where you wish to measure
current.
7) Touch the black test probe tip to the negative side of
the circuit. Touch the red test probe tip to the positive
side of the circuit.
8) Apply power to the circuit.
9) Read the DC current measurement on the display.

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AC CURRENT MEASUREMENT
1) Insert the black test lead into the negative COM jack.
2) For current measurements up to 4000 µ A AC, set the
function switch to the µ Aposition and insert the red
test lead banana plug into the µ Ajack.
3) For current measurements up to 400mA, set the
function switch to the mA position and insert the red
test lead banana plug into the mA jack.
4) For current measurements up to 10A AC, set the
function switch to the 10A position and insert the red
test lead banana plug into the 10A jack.
5) Use the MODE button to select AC or DC Current.
"AC" must appear on the display.
6) Remove power from the circuit under test, then open
the point in the circuit where you wish to measure
current.
7) Touch the black test probe tip to the negative side of
the circuit. And touch the red test probe tip to the
positive side of the circuit.
8) Apply power to the circuit.
9) Read the AC current measurement on the display.

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RESISTANCE [ Ω] MEASUREMENT
WARNING: To avoid electric shock, disconnect
power to the unit under test and discharge all
capacitors before taking any resistance
measurements.
1) Set the function switch to the Ωposition.
2) Insert the black test lead into the negative COM jack
and the red test lead plug into the positive Ω jack.
Press the MODE button until "MΩ" appears on the
display.
3) Touch the test probe tips across the circuit or part
under test. It is best to disconnect one side of the part
under test so the rest of the circuit will not interfere
with the reading.
4) Read the resistance measurement on the display.
CONTINUITY CHECK
WARNING: To avoid electric shock, disconnect
power to the circuit under test and discharge all
capacitors before taking any continuity
measurements.