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Model 4277A
SECTION III
EXTERNAL DC BIAS OPERATION {<±200V)
DC VOLTAGE
SOURCE
To
make
eapaeitanee
measurements
using
externally supplied dc bias voltages up to ±200V,
use the HP 16065A Test Fixture. Connect a dc
voltage source to the 16065A as shown in the
diagram.
CAUTION
9. Connect
a
sample to the
16065A test
fixture.
CAUTION
DO NOT SHORT THE HIGH AND LOW
TERMINALS.
DO
NOT
APPLY
GREATER
THAN
±40V TO THE 4277A'S EXT INPUT/INT
MONITOR
CONNECTOR.
IF
THE
APPLIED VOLTAGE EXCEEDS ±40V,
THE 4277A MAY BE DAMAGED.
PROCEDURE:
1. Set DC BIAS select switch on rear panel to
OFF,
2. Set CABLE LENGTH switch on the front
panel to Im.
3. Connect the 16065A to the UNKNOWN
terminals of the 4277A.
4. Connect the dc voltage source to DC BIAS
INPUT connector of the 16065A.
5. Connect a DVM or an oscilloscope to the
DC
BIAS
MONITOR
connector
of
the
16065A.
6. Turn on the instruments.
7. Set the 4277A*s controls as described in
steps 5 through 7 of Figure 3-20. Set the
DISPLAY A function to "C" measurement
mode.
CAUTION
WHEN A POSITIVE BIAS VOLTAGE IS
USED, THE POSITIVE TERMINAL OF
ELECTROLYTIC CAPACITORS MUST
BE
CONNECTED
TO
THE
INSTRUMENT'S
HIGH
TERMINAL.
WHEN
USING
A
NEGATIVE
BIAS
VOLTAGE,
CONNECT
THE
CAPACITOR'S NEGATIVE TERMINAL
TO
THE
INSTRUMENT'S
HIGH
TERMINAL,
10. Set the external dc voltage source to the
desired output voltage and close the cover
of the 16065A.
11. Read the measured values.
Wait until the
monitored voltage becomes stable.
12. Open the cover of the 16065A.
When
the
cover
of
the
16065A
is
opened, the charge on the sample is
discharged through two paralleled 20S7
resistors.
8. Perform OPEN and SHORT Zero Offset
Adjustments.
Figure 3-23. External DC Bias (Sheet 2 of 4).
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