Handling And Maintenance - Maxwell 25303 User Manual

EN
User Manual
1. LCD: display the measuring value and unit.
2. Function key
2-1. Power and backlight switch: turn on/off the
power and backlight.
2-2. PK HOLD key: press it, the max. of presently
measured value is held on LCD and PH symbol
displays. Press it again, PH symbol disappears,
and the meter is exited the holding mode.
2-3. Transistor test jack.
2-4. DC/AC key set DC or AC working mode.
3. Range knob: to select measuring function
and range.
4. Voltage, resistance and frequency port
5. Common measuring port (COM)
6. Port for measuring current less than 200mA
7. Port for measuring current 20A
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The signs near the connectors warn if the
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inward voltage or current values are above the
set values. These help to avoid damage to the
inner circuits.
Set the proper function with the function
•
selection switch before measuring.
If you do not know the measured value range,
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set the switch to the highest available setting
and go backwards until you reach the proper
setting.
DC and AC voltage measurement
Connect the black wire to the „COM" connector
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and the red one to the „VΩHz" connector.
By default the automatic range switch is
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active, which is indicated by the AUTO sign on
the display. You can set the following ranges
manually by pressing the RANGE button: 400
mV/4 V/40 V/400 V/1000 V.
Set the function selection switch to the proper
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V setting and connect the wires parallelly for
the measurement.
DC and AC current measurement
Connect the black wire to the „COM", and the
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red one to the „mA" or „10A" connectors for 400
mA or 10A measurement.
Set the proper range with the function switch.
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Connect the connectors to the power source
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parallelly.
To measure current between 400 mA and 10 A
•
follow the instructions above, but connect the
red wire to the „10A" connector.
Resistance measurement
Connect the black wire to the „COM" and the
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red one to the „V/ΩHz" connector.
Set the function switch to the desired
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resistance range.
Connect the wires parallelly.
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Press the "RANGE" button for selecting the
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automatic/manual range.
Warning: Make sure the measured circuit is not under
power!
Capacity measurement
Set the function selection switch to the -ll-
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setting.
Press the „REL" button to clear the display.
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Connect the black wire to the „COM" and the
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red one to the „V/Ω" connector. Touch the
wires to the connectors of the capacitor. Pay
attention to the polarity.
Note:
Capacity measurement has automatic range selection.
Unit: 1 nF=10 -3 μF or 1000 pF.
Do not connect an external voltage source or a
charged capacitor (especially high capacity ones)
to the connectors. Discharge the capacitors before
measurement. Electrolyte capacitors should be
discharged multiple times.
Diode and continuity test
Connect the black wire to the „COM" connector
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and the red one to the „VΩHz" connector.
(Note: the polarity of the red wire is +)
Set the function switch to the position.
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Touch the wires to the connectors of the
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diode. The display shows the opening voltage
of the diode.
Connect the wires to the two points of the
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circuit. If the resistance is below 50 Ω, the
device will beep.
Transistor hFE test
Set the function switch to the hFE position.
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Determine whether the transistor is NPN or
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PNP and place it into the proper connector
(this connector is included and connects to the
mA + COM connectors).
The transistor's amplification factor is
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displayed on the screen.
I = 15 μA, V = 1,5 VBC
Frequency measurement
Connect the measuring wire or shielded cable
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to the „COM" and „VΩHz" connectors.
Set the function switch to „30MHz" and touch
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the wires to the signal source.
Note:
Do not measure frequency on higher voltage than
•
250V(RMS)
In a noisy environment it is recommended to use a
•
shielded wire when measuring weak signals.
Avoid touching the circuit when measuring high
•
voltage.
Range selection is always automatic when measuring
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frequency.
Duty cycle measurement
Set the function selection switch to 30MHz and
press the Hz/DUTY button once to measure
duty cycle.
Data hold function
By pressing the HOLD button the actual
measured value gets held on the screen until
the button is pressed again.
Warning
When measuring voltage make sure that the wires do
•
not connect to the current measurement connector
and the function switch is not in a resistance or diode
measurement position. Always make sure that the wires
are connected to the proper connector.
Take care when measuring voltage above 50V, especially
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with high power devices.
Avoid connecting to 'live' circuits.
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When measuring current make sure the circuit is not
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under voltage before connecting the multimeter.
Before measuring resistance and diode make sure the
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power is disconnected for the time of measuring.
Always use the proper function and measuring range.
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If you are unsure about the range, select the highest
available and move backwards from that.
Make sure that the measuring wires and their insulation
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are intact.
User Manual
Be careful, do not go over the specified overload
•
thresholds.
Only replace fuses to those of the same type and value.
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When opening the lid of the device for replacing fuses or
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batteries make sure that all external power sources are
disconnected and the function switch is in OFF state.
H
andlinG and
M
aintenance
Handling
Keep the multimeter dry at all times. If it
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becomes wet, wipe it immediately. Liquid may
corrode the circuits.
The multimeter may be stored and
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operated only at normal temperatures. High
temperatures reduce the lifetime of electric
devices, damages the batteries and distorts/
melts the plastic parts.
Handle the multimeter with care. Dropping
•
it may result in damage to the circuits and
the surface which may cause improper
functioning.
Protect the multimeter from dust and other
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dirt which may cause the untimely wearing of
the parts.
Clean the multimeter with a wet cloth. Do not
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use chemicals, solvents or strong detergents
for cleaning.
Maintenance
Battery replacement (9 V)
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Disconnect all external circuits from the
•
device. Turn it off and remove all measuring
wires.
Unscrew the bottom lid.
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Remove the depleted battery and replace to
•
one of the same type.
Fuse replacement
Disconnect all external circuits from the
•
device. Turn it off and remove all measuring
wires.
Unscrew the bottom lid.
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Remove the melted fuse and replace to one of
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the same type and value.
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