A-4
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 mV p-p
Test Procedure:
a. Connect the test equipment as shown in Figure A-5.
b. Turn the unit's power on and turn CURRENT control fully clock-
wise.
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 bandwidth to 20 MHz.
e. Check that the peak-to-peak noise is no more than 2 mV.
Figure A-5. Peak-to-Peak Measurement Test Setup
Constant Current(CC) Tests
For output current measurements the current sampling resistor must
be treated as a four terminal device. In the manner of a meter shunt,
the load current is fed to the extremes of the wire leading to the resis-
tor while the sampling terminals are located as close as possible to
the resistance portion itself. Generally, any current sampling resistor
should be of the low noise, low temperature coefficient type end
should be used at no more than 5% of its rated power so that its tem-
perature rise will be minimized.
Load Effect(Load Regulation)
Definition:
CC Load Effect is the change in dc output current when
load resistance changes from short circuit to full load or from full load
to short circuit.
Test Parameter:
Measured Variable: Output Current
Expected Results: Less than 0.01% plus 1 mA
Test Procedure:
a. Connect the DVM across R
s
in Figure A-2. Operate the elec-
tronic load in constant voltage mode and set its voltage to the
full rated value of power supply.
b.
Turn the unit's power on and turn VOLTAGE control fully clock
wise.
c.
Turn 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
s
.
e.
Operate the electronic load in short(input short mode).
f.
When the reading settles, record voltage across R
s
again.
Check that the two recorded readings differ no more than
0.01% of output current plus 1 mA.
Source Effect(Line Regulation)
Definition:
Source Effect is the change in dc output current when the
ac input voltage changes from the minimum to maximum val ue(± 10%
of nominal voltage).
Test Parameter:
Measured Variable: Output Current
Expected Results: Less than 0.01% plus 1 mA
Test Procedure:
a. Connect the DVM across R
s
in Figure A-2. Operate the elec-
tronic load in constant voltage mode and set its voltage to the
full rated value of power supply.
b.
Connect the unit to the ac power line through a variable autotrans-
former that set for low line voltage(104 Vac for 115 Vec).
c.
Turn the unit's power on snd turn VOLTAGE control fully clock wise.
d. Turn 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.
e.
Record output voltage across Rs and convert it to current through
dividing by R
s
.
f.
Adjust autotransformer to the high line voltage(127 Vac for 115 Vac).
g.
When the reading settles, record the voltage across R
s
again.
Check that the two recorded readings differ no more than 0.01%
of output current plus 1 mA.
PARD(Ripple and Noise)
Definition:
Periodic and random deviation(PARD) in the unit's output
ripple and noise combine to produce a residual ac current as well as
Summary of Contents for E361 A Series
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