DM391/393-MAN
P. 5
Tips for Measuring Capacitance
• In capacitance, the meter is always autoranging
• In 40nF range, the readings are probably unstable due to
environmentally induced electrical noise and floating capacity
of the test leads. Therefore, directly connect the object to be
measured to the input terminals. Use “
REL
∆
” in this range for
accurate measurement - The meter will display 0.33 nF with
no connectors
Temperature (Temp) Measurements (DM393 only)
• The meter comes with temperature reading in either Centigrade
or Fahrenheit preset at the factory - The reading mode can be
changed at the factory only
*The “
SELECT
” function is not available in temperature mode.
WARNING!
DO NOT
apply thermocouple to circuits exceeding 30V rms, 42.4V peak
or 60V DC.
• Be sure to insert the banana plug K-type temperature bead probe
with c - polarities - You can also use a thermocouple
probe adapter (optional purchase) to adapt other standard
K-type thermocouple probes
Current (µA, mA, 10A) Measurement
WARNING!
Never attempt an in-circuit current measurement where the open-circuit
potential to earth is greater than 1000V. You may damage the meter or
be injured if the fuse blows during such a measurement.
CAUTION!
Check the meter fuses before measuring current. Use the proper
terminals, functions, and range for current measurements. Never place
the probes in parallel with any circuit or component when the test leads
are plugged into the current terminal.
Current is the flow of electrons though a conductor. To measure current
you must open the circuit under test, then place the meter in series with
the circuit.
Ranges available in current functions are:
400.0µA, 4000µA, 40.00mA, 400.0mA, 4.000A, 10.00A
The meter defaults at DC. Press “
SELECT
” push-button
momentarily to select “
AC
”.
Measuring AC or DC Current
1. Turn off power to the circuit and discharge all high-voltage ca p a c i t o r s .
2. Insert the black lead into the “
COM
” terminal and the red lead
into an input terminal appropriate for the measurement range as
the following table.
*To avoid blowing the meter’s 440 mA fuse, use the mAµA terminal only if you are sure the current is
less than 400 mA.
3. Open the current path to be tested. Touch the red probe to the
more positive side of the break and touch the black probe to the
more negative side of the break. (Reversing the leads will produce
a negative reading, but will not damage the meter).
4. Turn on power to the circuit and read the display.
5. After measuring current, turn off power to the circuit and
discharge at high-voltage capacitors. Disconnect the meter and
restore the circuit to normal operation.
Range
Input
Ranges
mAµA
400.0 µA, 4000 µA
mAµA
400.0 µA, 4000 µA
10A
4.000 A, 10.00 A
