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POWER SUPPLY
UNDER TEST
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E3610A
E3611A
E3612A
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2.6 ohm
13.3 ohm
120 ohm
-RMS
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Figure A-4. RMS Measurement Test Setup
PARD(Peak-to-Peak) Measurement
Test Parameter:
Measured Variable: Output voltage(peak-to-peak)
Expected Results: Less than 2 m V p-p
Test Procedure:
a. Connect the test equipment as s h o w n in Figure A - 5 .
b. Turn the u n i t ' s p o w e r on and turn CURRENT control fully
c l o c k w i s e .
c. Turn up output voltage to the full rated value. Check that the
unit's CV Indicator remains lighted. Reduce VOLTAGE control
if not lighted.
d . Set the oscilloscope to AC mode and b a n d w i d t h to 10 MHz.
e. Check that the peek-to-peak noise is no more than 2 m V .
the load current is fed to the extremes of the wire leading to the
resistor while the sampling terminals are located as close as possible
t o the resistance portion itself. Generally, any current sampling
resistor should be of the l o w noise, l o w temperature coefficient type
arxl should be used at no more than 5 % of its rated p o w e r so that its
temperature rise will be minimized.
Load Effect(Load Regulation)
Definition : CC Load Effect is the change in dc output current w h e n
load resistance changes f r o m short circuit to full load or f r o m full load
to short circuit.
Test Parameter:
Measured Variable: Output Current
Expected Results: Less than 0 . 0 1 % plus 1 m A
Test Procedure:
a. Connect the D V M across R, in Rgure A - 2 . Operate the
electronic load in constant voltage mode and set its
voltage to the full rated value of p o w e r supply.
b. T u r n the u n i t ' s p o w e r on and t u r n VOLTAGE control fully
c l o c k w i s e .
c. T u r n up output current to the full rated value. Check that the
AMPS display reads full rated values and CC indicator remains
lighted. Reduce CURRENT control if not lighted.
d . Record the voltage across Rs and convert it to current
through dividing by R,.
e. Operate the electronic load in short(input short mode).
f. W h e n the reading settles, record voltage across R, again.
Check that the t w o ' recorded readings differ no more than
0 . 0 1 % of output current plus 1 m A .
Source Effect(Line Regulation)
Definition: Source Effect is the change in dc output current w h e n the
ac input voltage changes f r o m the m i n i m u m to m a x i m u m val-
ue( ± 1 0 % of nominal voltage).
POWER SUPPLY
UNDER TEST
RL
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E3610A
E3611A
E 3612 A
2.6 ohm
•
13.3 ohm
•
120 ohm
Figure A-5. Peak-to-Peak Measurement Test Setup
Test Parameter:
Measured Variable: Output Current
Expected Results: Less than 0 . 0 1 % plus 1 m A
Test Procedure:
a. Connect the D V M across R, in Figure A - 2 . Operate the
electronic load in constant voltage mode and set its voltage to
the full rated value of p o w e r supply.
b. Connect the unit to the ac p o w e r line through a variable
autotransformer that set for l o w line v o l t a g e ( 1 0 4 Vac for
1 1 5 Vac).
c. Turn the u n i t ' s p o w e r on and turn VOLTAGE control fully
c l o c k w i s e .
d . Turn up output current to the full rated value. Check that the
AMPS display reads full rated values and CC IrKlicator remains
lighted. Reduce CURRENT control if not lighted.
e. Record output voltage across Rs and convert it to current
t h r o u g h dividing b y R, .
f. Adjust autotransformer to the high line voItage(127 Vac for
1 1 5 Vac).
g. W h e n the reading settles, record the voltage across R, again.
Check that the t w o recorded readings differ no more than
0 . 0 1 % of output current plus 1 m A .
Constant Current(CC) Tests
For output current measurements the current sampling resistor m u s t
be treated as a four terminal device. In the manner of a meter shunt.
PARD(Ripple and Noise)
D e f i n i t i o i i : Periodic and rarxJom deviation(PARD) in the u n i t ' s output
ripple and noise combine to produce a residual ac current as well as
A-4
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