Operation Procedures; Dc Voltage Measurement - Brother HD-390I Operator's Instruction Manual

or damp places. Although very rugged， the meter is a
sensitive measuring device and should be handled carefully
& properly.
7. Do not check resistance， transistor， diode， LED， or
capacitance when live voltage or current input across the
circuit.
8. When the meter is not in use， keep the selector switch to
the "OFF" range position， this provides direct short across
meter movement for minimum needle bounce when
transporting meter.
9. If you should accidentally apply excessive voltage or current
on a certain range， disconnect the leads from the circuit as
quickly as possible， check instrument operation on that
range by applying peoper input. If the meter does not operate
peoperly， check fuse. If it is blown replace it. (See fuse
replacement.)

OPERATION PROCEDURES

DC Voltage Measurement

WARNING: WITH EXTREME CARE WHEN MAKING
MEASUREMENTS FOR HUGE VOLTAGE. DO NOT TOUCH
TERMINAL OR PROBE ENDS.
1. Set the selector switch to the appropriate DCV range to be
used.
2. Connect the BLACK test lead to the "-COM" jack and the RED
test lead to the "+" jack.
3. If you know the polarity of the circuit to be tested， connect the
black probe to the negative side.
4. If you don't know the polarity， connect the probes to opposite
sides of the circuit and watch the pointer. If it goes to the left，
reverse the probes. The RED probe will be connected to the
positive.
6