Tektronix 7a11 Instruction Manual page 54

j . Disconnect the
P
robe from the Stored
P
robe In put
Adapter .
R
emove the coaxial cable from the Am plitu de
Calibrator And Comp arator or from
t
he Oscilloscope Cali-
brator .
k .
P
u sh
t
he 7Α11 Offset OFF button to its inward
position .
8. Check In put Gate Current
REQUIREMENT: 0.25 ηΑ or less at 25 ° C.
α . Control settings given in Table 5-2 apply, except that
the VOLTS/DIV control is at 5 mV .
b. Set the trace accurately to graticule vertical center,
using the 7Α11
P
OSITION control .
ε.
C
HECK-Gate current. Connect the 50 Ω Termin-
ation/Adapter to the
P
robe an d note accom panying trace
shift. Trace shift should be within 0.05
d
ivision, in dicating
0.25 ηΑ or less gate current. (Values apply when ambient
temperature is app roxi mately 25 ° C . See Specification
Section for values app licable at other temperatures .)
d. Disconnect the 50 Ω Termination/Ada p ter from the
P robe .
9. Check Drift With Ti me
Ο
REQUIREMENT :
W
ith ambient te mp erature and line
v
oltage constant, drift with time should be with in 0.1
division du ri ng any 1 minute interval with in ϊ
h
our after
20 minutes from turn-on, and
s
hou ld be within 0.3
divί sioη
d
uring any
h
our after 20 minutes from turn-on .
α. Control settings app ear in Table 5-2, except that the
VOLTS/DIV switch is at 5 mV . The 7Α11 must
h
ave been
operating continuo u sly for at least 20 minutes since the last
time it was energized .
b. CHECK-Short-term
d
rift . Trace shift should
b
e with-
in 0.1
d ivision over any 1-minute interval .
ε. (O ptional .) CHECK-Long-term
d rift . Trace position
should remai n withi n α 0.3
d ivision area d uring the next
hour.
10 . Chec k IDENTIFY operation
Low- I- rε g c ι e η cγ
Sine
V
ντ3νe
Gene r'ltur
F
ig . 5-9. Equipment for step 11 .
P
erformance Check/Calibration-7A11
REQUIREMENT : IDENTIFY controls should be
capable of causing app roximately 1/4
d
ivision of trace
shift.
α. Control settings given in Table 5-2 apply .
b .
CHECK-Probe IDENTIFY operation. De press an d
release the IDENTIFY button on the
P
robe and observe
that app roximately 1/4
d
ivision trace shift accompanies the
action .
ε. CH ECK-Front-panel IDENTIFY operation .
R
epeat
the operatio n described in
p
art b., using the front-panel
IDENTIFY button .
11 . Check AC-Cou ple d
L
ow-Fre quency Response
REQUIREMENT : Low-Frequency -3 dB
p
oint at 15 Hz
with AC-Cou pler attached to
P
robe .
α. Control settings given in Table 5-2 apply.
E
quipment
req uire d for step 11 is shown in F ig . 5-9.
b. Set the 7A 11 VOLTS/DIV to 50 mV .
c. Set the
L
ow-Frequency Sine
W
ave Generator (ite m 8)
Am plitu de to mini mum.
εβΝC-temale
to Dual
Stored Probe
AC
Banana-Plug 'I nput Adapter' Couple
Adapter
5-13