Technical data

Service and Maintenance 8
Constant Current (CC) Verifications
E364xA User’s and Service Guide 197
CC load effect (load regulation)
This test measures the immediate change in output current
resulting from a change in the load from the full rated
output voltage to short circuit.
1 Turn off the power supply and connect the output to be
tested as shown in
Figure 8- 1 with the digital voltmeter
connected across the 0.01 Ω current monitoring resistor
(R
M1
).
2 Turn on the power supply. Select the low voltage range
(8 V/3 A)
[1]
, enable the output, and set the display to the
limit mode. When the display is in the limit mode,
program the output voltage to the maximum
programmable value and the output current to the
full- scale rated value (3 A)
[1]
.
3 Set the voltage of the electronic load to 8.0 V to operate it
in the constant voltage mode since a voltage drop occurs
on the load wires. Check that the CC annunciator is
turned on. If it is not, adjust the load so that the output
voltage drops slightly. Record the current reading by
dividing the voltage reading on the digital voltmeter by
the resistance of the current monitoring resistor.
4 Operate the electronic load in the short (input short)
mode. Record the current reading immediately by dividing
the voltage reading on the digital voltmeter by the
resistance of the current monitoring resistor. The
difference between the current readings in
step 3 and
step 4 is the load regulation current. The difference of the
readings during the immediate change should be within
the following limits:
[1] For the E3640A model. For other models, refer to Tabl e 8 -5 .
E3640A E3641A E3642A E3643A E3644A E3645A
0.55 mA 0.33 mA 0.75 mA 0.39 mA 1.05 mA 0.47 mA