HP 3478A Technical Manual page 23

all full scale inputs (e.g. 10V input to the A/D for 30mV, all full scale inputs (e.g. 10V input to the A/D for 30mV,
300mV, 3V, etc. inputs to the 3478A). 300mV, 3V, etc. inputs to the 3478A).
3-21. 1. 3-2 When the When the DC V DC Volt
right side of the display shows "MVDC" or "VDC", right side of the display shows "MVDC" or "VDC",
dependent on the range selected. The reading can be dependent on the range selected. The reading can be
displayed either as a 5 1/2, 4 1/2, or 3 1/2 digit reading, displayed either as a 5 1/2, 4 1/2, or 3 1/2 digit reading,
dependent on the selected Number Of Digits Displayed dependent on the selected Number Of Digits Displayed
(see paragraph 3-54 (see paragraph 3-54). Refer to ). Refer to Table 1-1
the DC Volts the DC Volts Function's accuracy specifications. Function's accuracy specifications.
3- 3-22 22. . AC Vo AC Volt lts M s Mea easu sure reme
3- 3-23 23. . Th The 3 e 347 478A 8A us uses
Converter to measure ac voltages from 1uV to 300V in Converter to measure ac voltages from 1uV to 300V in
four ranges: 300mV, 3V, 30V, and 300V. The response four ranges: 300mV, 3V, 30V, and 300V. The response
of the converter is from 20Hz to 100KHz on all ranges (to of the converter is from 20Hz to
300KHz on the 30V Range only). All ranges are 300KHz on the 30V Range only). All ranges are
protected from input voltages up to 450V peak. Select protected from input voltages up to 450V peak. Select
the AC Volts Function for ac volts measurements by the AC Volts Function for ac volts measurements by
pressing the - v button. pressing the - v button.
3-2 3-24. 4. The AC The AC to to DC C DC Conv
voltage to dc volts, which is then measured by the voltage to dc volts, which is then measured by the
3478A's A/D Converter. All ranging is done in the AC to 3478A's A/D Converter. All ranging is done in the AC to
DC Converter, applying the same voltage value to the DC Converter, applying the same voltage value to the
A/D Converter for all full scale inputs. A/D Converter for all full scale inputs.
3-2 3-25. 5. When the When the AC V AC Volt
right side of the display shows "MVAC" or "VAC", right side of the display shows "MVAC" or "VAC",
dependent on the range selected. The reading can be dependent on the range selected. The reading can be
displayed either as a 51/2, displayed either as a 51/2, 41
dependent on the selected Number of Digits Displayed dependent on the selected Number of Digits Displayed
(see paragraph 3-54. (see paragraph 3-54.) A .6 second delay is also applied ) A .6 second delay is also applied
in the ACV Function before a reading is taken (also, in the ACV Function before a reading is taken (also,
during a range change). Refer to Table 1-1 during a range change). Refer to
for the AC Volts for the AC Volts Function's accuracy specifications. Function's accuracy specifications.
3- 3-26 26. . Resi sist stan Re ance Me ce Meas
3- 3-27 27. . The Th e 34 3478 78A A
measurements from .0001 ohms to 30M ohms in seven measurements from .0001 ohms to 30M ohms in seven
ranges. The ranges extend from the 30 ohm to the 30M ranges. The ranges extend from the 30 ohm to the 30M
ohm range. All ranges are protected from input voltages ohm range. All ranges are protected from input voltages
up to 350V peak. Resistance measurements can be up to 350V peak. Resistance measurements can be
made using either the 2-Wire or 4-Wire ohms made using either the 2-Wire or 4-Wire ohms
configuration, which are selected by the 2 WIRE configuration, which are selected by the 2 WIRE
WIRE WIRE buttons, respectively. Refer t buttons, respectively. Refer to Figure 3-4
Ω Ω
correct ohms connections. correct ohms connections.
3-28. 8. 3-2 Res Resist istanc ance mea e measur
a known current (generated by the 3478A) to the a known current (generated by the 3478A) to the
unknown resistance. The resultant voltage drop is then unknown resistance. The resultant voltage drop is then
measured by the 3478A's dc circuitry (Input Circuitry and measured by the 3478A's dc
A/D Converter). In the 2-Wire Ohms Function, the A/D Converter). In the 2-Wire Ohms Function, the
voltage drop is measured across the HI and LO INPUT voltage drop is measured across the HI and LO INPUT
Terminals. In the 4-Wire Ohms Function, the voltage is Terminals. In the 4-Wire Ohms Function, the voltage is
measured across the HI and LO measured across the HI and LO
olts Fu s Funct nction ion is s is sele electe
Table 1-1 or or Table 4-1 Table 4-1 for
ment nts s
es a Tr a True ue RM RMS A S AC t C to D
100KHz on all ranges (to
onvert erter c er chan hanges ges th the ac e ac inp
olts Fu s Funct nction ion is s is sele electe
41/2, /2, or 31/2 digit reading, or 31/2 digit reading,
Table 1-1 or or Table 4-1 Table 4-1
asur urem emen ents ts
is is ab able le to t o ma make ke r res
o Figure 3-4 for the
sureme ements nts are are mad made by e by app
circuitry (Input Circuitry and
SENSE Terminals. SENSE Terminals.
Ω Ω
The Ohms Current Source generates the known The Ohms Current Source generates the known current
cted, d, the the
for
o DC C
input ut
cted, t d, the he
which is applied to the unknown resistance (in both ohms which is applied to the unknown resistance (in both ohms
functions) from the HI INPUT Terminal. The current functions) from the HI INPUT Terminal. The current
values are as follows: values are as follows:
esis ista tanc nce e
and 4 and 4
Ω Ω
for the
3-29. 9. 3-2
apply lying ing
side of the display shows either "OHM", "KOHM", or side of the display shows either "OHM", "KOHM", or
"MOHM", dependent on the range selected. In addition, "MOHM", dependent on the range selected. In addition,
the "2 the "2
3-4 3-4
Figure 3-4. Ohms Connections Figure 3-4. Ohms Connections
R R a a n n g g e e
3 3 0 0 o o h h m m
3 3 0 0 0 0 o o h h m m
3 3 K K o o h h m m
3 3 0 0 K K o o h h m m
3 3 0 0 0 0 K K o o h h m m
3 3 M M o o h h m m
3 3 0 0 M M o o h h m m
When an When an Ohms Ohms Fun Functi ction
" annunciator is on for the 2-Wire Ohmns " annunciator is on for the 2-Wire Ohmns
Ω Ω
TM 11-6625-3071-14 TM 11-6625-3071-14
current
C C u u r r r r e e n n t t
1 1 m m A A
1 1 m m A A
1 1 m m A A
1 1 0 0 0 0 u u A A
1 1 0 0 u u A A
1 1 u u A A
1 1 u u A A
on is s is sele electe cted, d, the the rig right ht