HP 3478A Technical Manual page 43

3478A 3478A
Figure 4-5. AC Current Accura Figure 4-5. AC Current Accuracy Test and
AC-DC Current Calibrator to AC-DC Current Calibrator to the IA
record the 3478A's reading. record the 3478A's reading.
j. j. Remove the AC Remove the AC Calibrator from Calibrator from the AC-DC
Calibrator. Calibrator. Remove the Remove
3478A. This completes 3478A. This completes the AC
fails, try calibrating the instrument (go to paragraph 4- fails, try calibrating the instrument (go to
94). If the t 94). If the test still fails, g est still fails, go to this
for troubleshooting. for troubleshooting.
4-69. 4-69. Ohms Ohms Test Test
4-70. The Ohms Test should 4-70. The Ohms Test should only be
function in w function in which the hich the 3478A was 3478A was last calibrated.
example, the 3478A was last calibrated in the 4-Wire example, the 3478A was last calibrated in the 4-Wire
Ohms Function, perform the Ohms Test in the 4-Wire Ohms Function, perform the Ohms Test in the 4-Wire
Ohms Function. Ohms Function. If the If the 3478A was
2-Wire Ohms Function, perform the Ohms Test in the 2-Wire Ohms Function, perform the Ohms Test in the
3478A 3478A
cy Test and Calibration Calibration
the IA Range. Range. Check and Check and
the AC-DC Current
the current current calibrator calibrator from th
the AC Current Current Test. Test. If any
paragraph 4-
o to this manual's Section VI manual's Section VII I
only be done in t done in the ohms
last calibrated. If, for
3478A was last calibrated last calibrated in the
Table 4-7. Ohms Test Table 4-7.
2-Wire Ohms Function. 2-Wire Ohms
connections or test leads used to calibrate the 3478A in connections or test leads used to calibrate the 3478A in
the 2-Wire Ohms Function must also be used when the 2-Wire Ohms Function must also be used when
testing t testing the multimeter
the impedance of the test leads is canceled out when the the impedance of the test leads is canceled out when the
multimeter is calibrated (in the 2-Wire Ohms Function). A multimeter is calibrated (in the 2-Wire Ohms Function). A
different set of test leads can have different impedances different set of test leads can have different impedances
which show up as an ohms test error. which show up as an ohms test error.
4-71. The Ohms Function 4-71.
using either full scale or 1/3 scale using either full
1K ohm resistors to check the 1K ohm resistor
of this, both test limits are in Table 4-7 of this, both test limits are in
Performance Test Card. The test step Performance Test Card.
Test Card) shown in parenthesis are for the 1/3 scale Test Card) shown in parenthesis are for the 1/3 scale
tests. When testing the 3478A, tests.
used to connect the standard resistor to the 3478A's used to connect the standard resistor to the 3478A's
INPUT Terminals INPUT Terminals are as
prevent the leads from picking up any noise, which could prevent the leads from picking up any noise, which could
give an invalid reading. give an invalid reading.
4-72. 4-72. If the
Function, all test resistors are applied to the 3478A's Function, all test resistors are applied to the 3478A's
Current
INPUT Terminals. INPUT Terminals. If the
from the e
tested, short the INPUT Terminals and connect the test tested, short the INPUT Terminals and connect the test
If any test test
resistors to the terminals, as shown in Figure 4-6 resistors to the terminals, as shown in
Figure 4-7, Figure 4-7, respectively.
4-73. The Ohms Test 4-73.
Test Card and in Table 4-7. Test Card and in
corresponds to a step in the procedure with each step corresponds to a step in the procedure with each step
number shown in parenthesis in the procedure. number shown in parenthesis in
he ohms
If, for
4-74. 4-74.
required test equipment for the Ohms Test. required test equipment for the Ohms Test.
in the
Ohms Test Limits Limits
4-10 4-10
Function. In In addition,
he multimeter in that in that function.
The Ohms Function of the of the 3478A can
scale or 1/3 scale inputs (e.g.
s to check the 3K ohm Range).
Table 4-7 and on the Ohms
The test step numbers (on th
When testing the 3478A, make sure the test leads
are as short as short as possible.
If the 3478A is t 3478A is to be test o be tested in the
If the 4-Wire Ohms Function is to 4-Wire Ohms Function is to be
respectively.
The Ohms Test limits are pr limits are printed on
Table 4-7. Each step on the test card Each step on the test card
Equipment Equipment Required. Required.
TM 11-6625-3071-14 TM 11-6625-3071-14
addition, the the same t same test
function. This is because This is because
3478A can be tested be tested
inputs (e.g. 3K ohm or 3K ohm or
3K ohm Range). Because Because
and on the Ohms
numbers (on the e
make sure the test leads
possible. This is to This is to
ed in the 2-Wire Ohms 2-Wire Ohms
Figure 4-6 and and
inted on the Ohms the Ohms
the procedure.
The following is the The following is the
est
be