Keysight e3620a, Operating And Owners Manual

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A-3
g. Push the V1 METER switch in to monitor the V1 supply's
output current.
h. Close the load switch and adjust V1 VOLTAGE control
until front panel ammeter indicates 1.000 A.
i. Check that DVM indicates a voltage drop across the cur-
rent sampling resistor that corresponds to a current of 1
amp ±(0.5% + 2 counts) (0.993 A to 1.007 A).
j. Open the load switch and repeat steps (f) through (i) for
the V2 supply.
Figure A-4. Output Current, Test Set Up
Current Limit
k. Disconnect all loads from the supply.
l.
Connect the test setup shown in Figure A-4 to the V1
supply's + and - output terminals. Substitute a short for R
L
and leave the load switch open.
m. Push the V1 METER switch in and adjust the V1 VOLT-
AGE control fully clockwise.
n. Close the load switch and determine the current flow
through the current sampling resistor R
S
by measuring its
voltage drop with the DVM. The current should be mini-
mum 1 A + 5%.
o. Open the load switch and repeat steps (k) through (n) for
the V2 supply.
Load Regulation (Load Effect)
Definition: The immediate change, E
OUT
, in the static value of
DC output voltage resulting from a change in load resistance from
open circuit to the value that yields maximum rated output current (or
vice versa).
To check the load regulation:
a. Connect the test equipment across the output of the V1 sup-
ply as shown in Figure A-5 . Operate the electronic load in
constant current mode and set its current to 1.000 A. Input
off the electronic load.
b. Turn on the supply. Push the V1 METER switch in and adjust its
voltage to 25.0 volts. Then input on the electronic load.
c. Record the voltage indicated on the DVM.
d. Operate the electronic load in open (input off) mode and
recheck the DVM indication immediately. The readings’
difference during the immediate change should be within
0.01% plus 2 mV of the reading in step (c).
e. Repeat steps (a) through (d) for the V2 supply.
Figure A-5. Basic Test Setup
Line Regulation (Source Effect)
Definition: The immediate change, E
OUT
, in the static value of
DC output voltage resulting from a change in AC input voltage from a
minimum to a maximum value (±10% of nominal voltage).
To check the line regulation:
a. Connect a variable autotransformer between the input
power source and the power supply line plug.
b. Connect the test equipment across the output of the V1 supply as
shown in Figure A-5 . Operate the electronic load in constant current
mode and set its current to 1.000 A. Input off the electronic load.
c. Adjust the autotransformer for a low line input (-10% of nominal
voltage).
d. Turn on the power. Push the V1 METER switch in and
adjust the output of the supply to 25.0 volts, then input on
the electronic load. Record the DVM indication.
e. Adjust the autotransformer for high line voltage input (+10%
of nominal voltage) and recheck the DVM indication immedi-
ately. The readings’ difference during the immediate change
should be within 0.01% plus 2 mV of the reading in step (d).
f. Repeat steps (b) through (e) for the V2 supply.
Ripple and Noise(Normal Mode Voltage)
Definition: Ripple and noise are measured in the rms or peak-
to-peak value over a 20 Hz to 20 MHz bandwidth. Fluctuations
below the lower frequency limit are treated as drift.
RMS Measurement
The rms measurement is not an ideal representation of the
noise, since fairly high output noise spikes of short duration
could be present in the ripple and not appreciably increase
the rms value.
To measure the ripple and noise of the rms value on each
output supply output:
a. Connect the test equipment across the output of the V1
supply as shown in Figure A-6 .
b. Turn on the supply and push the V1 METER switch in.
c. Adjust the output of the V1 supply to 25.0 volts.
d. Check that the rms noise voltage at the true rms voltme-
ter is less than 0.35 mV.
e. Repeat steps (a) through (d) for the V2 supply.
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