22
f.
Turn the power off and disconnect the test leads.
This range is only intended for measurements in low voltage circuits (under 25 V
DC) such as the primary power in vehicles or their accessories.
3.11.3
Direct Current Measurement 0-10A Range
a.
Plug the black test lead into the -10A jack and the red test lead into the +10A
jack.
b.
Set the range switch at 10 AMPS (dual position with 10mA).
c.
Open the ground side of the circuit in which the current is being measured.
Connect the VOM in series with the circuit, connecting the red test lead to the
positive side and the black test lead to the negative side.
NOTE:
The function switch has no effect on polarity for the 10 AMPS range.
d.
Turn the power on. Read the current directly on the black DC scale. Use the
0-10 figures to read directly in amperes.
e.
Turn the power off and disconnect the test leads.
The 10A range is not internally fused in the 260. When using the 10A range, never
disconnect a test lead from a jack or from the circuit while the circuit is energized.
Doing so may damage the test jacks or leads and the arcing may be hazardous to
the operator. Turn off circuit power and wait for the meter reading to drop to zero.
The polarity reversing feature of the function switch does not operate on the 0-10A
range. If polarity is found to be incorrect, turn off circuit power, wait for the meter
indication to read zero and then interchange test lead connections to the circuit.
3.12 Zero Ohms Adjustment
When resistance is measured, the INTERNAL batteries B1 and B2 furnish power
for the circuit. Since batteries are subject to variation in voltage and internal resis-
tance, the Instrument must be adjusted to zero before measuring a resistance, as
follows:
a.
Turn range switch to desired ohms range.
b.
Plug the black test lead into the -COMMON jack and the red test lead into the
+jack.
c.
Connect the ends of test leads together to short the VOM resistance circuit.
d.
Rotate the ZERO OHMS control until pointer indicates zero ohms. If pointer
cannot be adjusted to zero, one or both of the batteries must be replaced.
(For battery replacement, refer to Section 4.)
e.
Disconnect shorted test leads.
!
!