Agilent Technologies E3620A Operating And Service Manual page 81

c. Connect the DVM across R
age mode.
d. Turn on the supply.
e. Record the voltage across R
dividing this voltage by R
Check that the current is less than 1 μA.
f.
g. Repeat steps (a) through (f) for the V2 supply.
Load Transient Response Time
Definition : This is the time for the output voltage to return to
within a specified band around its voltage following a change
from full load to half load or half load to full load.
To measure the load transient response time:
a. Connect the test equipment across the output of the V1
supply as shown in Figure A-7, but replace the DVM with
the oscilloscope. Operate the electronic load in constant
current mode.
b. Turn on the supply and push the V1 METER switch in.
c. Turn up V1 output voltage to 25.0 volts.
d. Set the electronic load to transient operation mode
between one half of supply's full rated value and supply's
full rated value at a 1 kHz rate with 50% duty cycle.
e. Set the oscilloscope for ac coupling, internal sync and
lock on either the positive or negative load transient.
. Operate the DVM in ac volt-
S
and convert it to current by
S
.
S
Figure A-9. Load Transient Response Time Waveform
f. Adjust the oscilloscope to display transients as shown in
Figure A-9.
g. Check that the pulse width (t
mV from the base line is no more than 50 μsec as shown.
h. Repeat steps (a) through (g) for the V2 supply.
Stability (Drift)
Definition: The change in output voltage (dc to 20 Hz) for the
first 8 hours following a 30-minute warm-up period with con-
stant input line voltage, constant load resistance and constant
ambient temperature.
To measure the stability:
a. Connect the test equipment across the output of the V1
supply as shown in Figure A-7.
b. Operate the electronic load in constant current mode and
set its current to 1.000 A.
c. Turn on the supply and push the V1 METER switch in.
d. Turn up V1 output voltage to 25.0 volts as read on the
digital voltmeter.
e. After a 30-minute warm-up, note the voltage on DVM.
f. The output voltage reading should deviate less than 0.1%
plus 5 mV from the reading obtained in step (e) over a
period of 8 hours.
g. Repeat steps (a) through (f) for the V2 supply.
A-6
-t ) of the transients at 15
2 1