Resistance Measurement; Continuity Measurement; Diode Test - Mastech MS8239A User Manual

Note
Before measuring current, first check the meter's
fuse. When measuring, use correct input end and
function. When the test probe is inserted to the
current input end, don't connect the other end of
the test probe with any circuit in parallel.

Resistance Measurement:

Rotate the function selection switch to an
1
appropriate resistance position, and turn off the
power to the circuit to be tested
2 Connect the black and red test probe to COM
input jack and VΩmA input jack, respectively.
3 Measure the resistance of the circuit with other
ends of test probes.
4
Read the resistance value from the LCD display.
Here are some tips for measuring resistance:
• The resistance measured on a circuit is usually
different from the rated value of resistance. This is
because the test current of the meter will flow
through all the possible channels between the
test probes.
• When measuring low resistance, to ensure the
accuracy of the measurement, make a short circuit
between the test probes and read the resistance
value of the short circuit. This resistance value
should be subtracted after measuring the
resistance to be tested.
09
• When there is no input (for example, open circuit),
the display will show "1", which means that the
measured value is out of range.
Warning
When measuring resistance or circuit continuity,
to avoid injury or meter damage, turn off the power
to the circuit and discharge all capacitors.

Continuity Measurement:

1
Rotate the function selection switch to continuity
measurement position, and turn off the power to
the circuit to be tested
2
Connect the black and red test probe to COM input
jack and VΩmA input jack, respectively.
3 Measure the circuit to be tested with other two ends
of the test probes.
4 If the measured circuit resistance is less than
about 50Ω, the buzzer will sound continuously.
Warning
When measuring resistance or circuit continuity,
to avoid injury or meter damage, turn off the power
to the circuit and discharge all capacitors

Diode Test:

1 Rotate the function selection switch to diode
position, and turn off the power to the circuit to
be tested
2 Connect the black and red test probe to COM input
jack and VΩmA input jack, respectively.
10