HP 3455A Operating And Service Manual page 55

Model 3455A
a. Connect the low output of the DC Standard to the
Low INPUT terminal of the 3455A. Using short clip
leads, insert the 1 megohm resistor in series between the
DC Standard's high output and the High INPUT ter-
minal of the 3455A. Connect a clip lead across the
resistor.
b. Set the 3455A controls as follows:
FUNCTION -..s'csdyesaewaser ens
RANGE ............ 00sec eee .
HIGH RESOLUTION
GUARD 0... eee ce cece eee eee nee
c. Adjust the DC Standard for a 3455A reading of
+ 10.00000 V.
d. Remove the clip lead from across the 1 megohm
resistor.
e. The 3455A reading should be between 9.99900 V
and 10.00000 V, verifying that the input resistance is
greater than 101° ohms.
f. Set the 3455A RANGE to 100 V; Auto-Cal OFF.
Reconnect the clip lead across the 1 megohm resistor.
g. Adjust the DC Standard for a 3455A reading of
+ 10.0000 V.
h. Remove the clip lead from across the 1 megohm
resistor.
i, The 3455A reading should be between + 9.0900 V
and + 9.0917 V, verifying that the input resistance is 10
megohms + 0.1%.
4-56. AC VOLTMETER INPUT IMPEDANCE TEST.
Equipment Required:
Test Oscillator (-hp- Model 652A)
Resistor (1 MQ + 0.1% -hp- Part Number
0698-6369)
Resistor (100 kQ2 0.1% -hp- Part Number
0811-1997)
a. Set the 3455A controls as follows:
Section IV
FUNCTION
RANGE ............
GUARD ih ics Geek noes escn ta teens
INPUT SELECT (rear panel) .... FRONT
AUTO-CAL. .2c0o5cGescsane' ek cae: ON.
b. Connect the Test Oscillator 50-ohm output (ter-
minated in 50-ohm load) to the 3455A front panel, IN-
PUT.
c. Set the Test Oscillator frequency to 50 Hz and ad-
just its output level for a 3455A reading of 1.00000 V.
d. Using short clip leads, insert the 1 megohm
resistor in series between the terminated Test Oscillator
output and the High INPUT terminal of the 3455A.
e. The 3455A reading should be between 0.66443 V
and 0.66887 V, verifying that the input resistance is 2
megohms + 1%.
f. Disconnect the resistor and reconnect the Test
Oscillator output to the 3455A INPUT.
g. Set the Test Oscillator frequency to 20 kHz and
adjust its output level for a 345SA reading of 1.00000 V.
h. Using short clip leads, insert the 100 kilohm
resistor in series between the terminated Test Oscillator
output and the High INPUT terminal of the 3455A.
i. The 3455A reading should be greater than
0.61017 V, verifying that the input shunt capacitance is
less than 100 pF.
j. Set the rear panel! INPUT SELECT switch to
REAR. Connect the Test Oscillator S0-ohm output (ter-
minated in 50-ohm load) to the 3455A rear-panel IN-
PUT.
k. Repeat Steps c through i to test the input im-
pedance at the rear INPUT terminals. In Step i, the
3455A reading should be greater than 0.70822 V verify-
ing that the rear terminal input shunt capacitance is less
than 75 pF.
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