Initial Display Test; Initial Control Settings; D/Qmeasurement; Lcr Measurement - HP 4262A Operating And Service Manual

Model 4262A
3-11. INITIAL DISPLAY TEST.
3-12. The Model 4262A automatically performs a
front panel LED display test for a few seconds
after instrument is tuned on (after LINE button is
depressed). The display test sequence is:
1. All front panel indicator lamps, except nu¬
meric segments and multiplier indicator
lamps will illuminate. (SRQ, LISTEN, TALK
and REMOTE lamps illuminate only when
HP-IB option is installed).
2. Front panel pushbutton LED's and indicator
lamps indicate that automatic initial settings
(see Paragraph 3-13 which follows) have been
set. Simultaneously, the LCR DISPLAY and
DQ DISPLAY readouts are tested. All nu¬
meric displays show figures of 8 (0) and
multiplier indicators (p
n/J
m k M) light in
turn.
3. Range indicator lamps step from right (upper
range) to left (lower range). When steps 1, 2
and 3 have been completed, the trigger lamp
begins to flash. Figures on numeric displays
change to meaningful numbers showing that
the 4262A is ready to take a measurement.
3-13. INITIAL CONTROL SETTINGS.
3-14. One of the sophisticated features of the
4262A is its automatic initial control setting func¬
tion. After the instrument is turned on, the front
panel control functions are automatically set as
follows:
SELF TEST...OFF
CIRCUIT MODE.AUTO
FUNCTION.C
LCR RANGE ..AUTO
LOSS.. . .. D
DQ RANGE...AUTO
TEST SIGNAL.1kHz
TRIGGER.INT
As these initial settings provide the general capa¬
citance measurement conditions applicable to a
broad range of capacitance measurements, a capa¬
citance can be usually measured by merely con¬
necting the sample to the UNKNOWN terminals.
Inductance or resistance can be measured by press¬
ing the L FUNCTION or R/ESR FUNCTION
buttons, as appropriate. When a different meas¬
urement is to be attempted, press appropriate
pushbuttons and select desired functions.
Section III
Paragraphs 3-11 to 3-18
3-15. D/QMEASUREMENT.
3-16. The Model 4262A makes a loss measure¬
ment along with capacitance or inductance meas¬
urements on each measurement cycle. The meas¬
ured loss factor is displayed in the form of the
dissipation (D) or quality (Q) factor of the sample.
The D or Q function is pushbutton selectable in
both L and C measurements. D and Q measure¬
ment ranges are:
D: 2 ranges .001 to 1.999
0.01 to 19.9
Q:
4 ranges .050 to 1.996
0.05 to 19.61
00.1 to 166.7
001 to 1000
The D range, appropriate to the value of the
sample is automatically selected. Alternately, a
manual D range control is pushbutton selectable.
Quality factor (Q) is calculated as a reciprocal
dissipation number from the measured D value.
Hence, the Q readout display will skip some
numbers when low dissipation samples are meas¬
ured. For example, when the dissipation measured
is .010, the quality factor display is 100. When
dissipation is .009, the quality factor reading is 111
(Q readings of 101 to 110 are not obtained). On
the high D measurement range, the readout is
displayed in 3 digits.
3-17. aLCR MEASUREMENT.
3-18. When many components of similar value
are to be tested, it is sometimes more practicable
to measure the difference between the value of the
sample and a predetermined reference value. The
a LCR function permits repetitive calculation of
the difference between the reference and each in¬
dividual sample and to display the result on the
LCR DISPLAY. When the alCR FUNCTION
button is pressed, the inductance, capacitance, or
resistance value of the sample is stored in an
internal memory. The 4262A will now display the
difference between the stored value and the meas¬
ured value of a sample connected to UNKNOWN.
The LCR RANGE is automatically held in
MANUAL for the duration of ALCR measurements
(if another pushbutton is inadvertently pressed,
the ^LCR measurement function will be reset and
will require reactivating).
3-7