IET Labs, Inc. RLC Digibridge 1693, User And Service Manual, Page: 155 / 171

131
1693 RLC Digibridge
Service and Maintenance
5.8.2 Capacitance Measurement
Accuracy (Ranges 1-3)
Make the test setup and verify instrument perfor-
mance as follows:
1. After the line voltage switch has been set to
correspond to the input line voltage, connect
the power cord and switch POWER ON.
2. Connect the 1689-9602 extender cable with
GR874 connectors as shown in section 3.2.13
on page 29.
3. Connect the “high” leads (red and red white)
to one of the 874 Tee connectors. Connect
the “low” leads (black and black/white) to
the other 874 tee.
4. Before measurement, zero the Digibridge
as follows:
In this process, the Digibridge automatically measures
stray parameters and retains the data, which it uses
to correct measurements so that results represent
parameters of the DUT alone, without (for example) test-
fixture or adaptor capacitance.
A. Be sure that MEASURE RATE is SLOW
and that the RANGE HELD indicator is
NOT lit. DO NOT have test voltage pro-
grammed to other than 1 V, nor frequency
to other than 1 kHz.
B. Leave the two type 874 tees connected
to the 1689-9602 extender cable, but not
connected to each other.
C. Press [FUNCTION] key (if necessary) to
select MEASURE function.
D. Press [MEASURE MODE] key (if neces-
sary) to select TRIGGERED mode.
E. Press these keys deliberately: [l] [6] [9] [3]
[=] [SHIFT] [OPEN].
F. Confirm that the GO indicator is lit. Press
the START button.
G. Keep hands and objects at least 10 cm
(4 in.) from test fixture.
H. Wait for the GO indicator to be lit
I. Connect the two type 874 tees together.
CAUTION
Be sure the line voltage switch, rear
panel, is correctly set for your power
line voltage.
J. Press these keys deliberately: [1] [6] [9] [3]
[=] [SHIFT] [SHORT].
K. Confirm that the GO indicator is lit. Press
the START button.
L. Wait for the GO indicator to be lit again,
on the keyboard (not on any remote test
fixture).
M. Disconnect the two type 874 tees from
each other.
5. Connect the type 874 tee with the red cables
to the HIGH terminal of the HACS-Z ca-
pacitance substituter. Connect the other tee
(black cables) to the LOW terminal of this
capacitor.
6. Set the decade capacitor dials to 00000 pF.
A. Press the C/D key.
B. Press these keys deliberately: [1] [6] [9]
[3] [=] [SHIFT] [OPEN].
C. Confirm that the GO indicator is lit. Press
the START button.
D. Wait for the GO light. The RLC display
should be .00000 pF.
E. Press [MEASURE MODE] key to select
CONT.
F. Press [EQUIVALENT CIRCUIT] key to
select SERIES.
7. Set the decade capacitor to 10 pF . If neces-
sary, press the START button. Verify that
the C and D measurements subsequently
displayed on the Digibridge are within the
limits given in the first line of Table 5-6.
8. Similarly, for each line in the table, set the
capacitor and the Digibridge measurement
rate, and verify that the resulting measure-
ments are satisfactory.
9. Disconnect the 1689-9600, BNC-T GR874
connectors extender cable from the capacitor
and the Digibridge
NOTE: Whenever doing short-circuit or open-circuit
zeroing, remember that the GO light to watch is the
one on the keyboard (not on any remote test fixture,
for example).
For more information on connecting to a HACS-Z
capacitance substituter see section 3.2.10.