Mastech ms8217, Руководство пользователя

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19 20
Ω
3.2.2 Resistance measurement
To avoid electrical shock and/or damage to the
instrument, disconnect circuit power and
discharge all high-voltage capacitors before
measuring resistance.
Warning
Resistance is an opposition to current flow.
The unit of resistance is the ohm (Ω). The Meter
measures resistance by sending a small current through
the circuit. Because this current flows through all
possible paths between the probes, an in-circuit
resistance reading represents the total resistance of all
paths between the probes.
The Meter's resistance ranges are 400.0Ω, 4.000kΩ,
40.00kΩ, 400.0kΩ, 4.000MΩ and 40.00MΩ.
To measure resistance (set up the Meter as shown in
figure 3):
1. Set the rotary switch to range.
2. Connect the black and red test leads to the COM and
VΩ terminals respectively.
3. Connect the test leads to the circuit being measured
and read the displayed value.
Some tips for measuring resistance:
• The measured value of a resistor in a circuit is often
different from the resistor's rated value. This is because
the Meter's test current flows through all possible paths
between the probe tips.
• In order to ensure the best accuracy in measurement
of low resistance, short the test leads before
measurement and memory the test probe resistance in
mind. This necessary to subtract for the resistance of
the test leads.
• The resistance function can produce enough voltage
to forward-bias silicon diode or transistor junctions,
causing them to conduct. To avoid this, do not use the
40MΩ range for in-circuit resistance measurements.
• On 40MΩ range, the meter may take a few seconds to
stabilize reading. This is normal for high resistance
measuring.
• When the input is not connected, i.e. at open circuit,
the figure "OL" will be displayed for the overrange
condition.
DIGITAL MULTIMETER DIGITAL MULTIMETER