Appendix Service Information
Constant Voltage (CV) Verifications
172
1Turn off the power supply and connect the output to be tested as shown in
Figure A-1 to an oscilloscope (ac coupled) between (+) and (-) terminals. Set
the oscilloscope to AC mode and bandwidth limit to 20 MHz. Connect a
resistive load (13.5 9)‡ to the terminal at (B) as shown above.
2Turn on the power supply. Select the high voltage range (20V/1.5A)†, enable
the output, and set the display to the limit mode. When the display is in the
limit mode, program the current to the full scale rated value (1.5 A)† and the
voltage to the full rated value (20.0 V)†.
3Check that the front panel CV annunciator remains lit. If not lit, adjust the load
down slightly.
4Note that the waveform on the oscilloscope does not exceed the peak-to-peak
limit of (5 mV)* or (8 mV)**.
5Disc,onnect the oscilloscope and connect the ac rms voltmeter in its place
according to the VRMS measurement techniques above and as shown above.
The rms voltage reading does not exceed the rms limit of 0.5 mV* or 1 mV**.
Note: For better measurement result, it is recommended to make the connection between
the BNC receptacle and the output terminals shorter as much as possible, and to use
the recommended split ferrites with the cable (BNC to BNC) as shown above.
Load Resistor
Input
RMS voltmeter
Load Resistor
Input
RMS voltmeter
(Front Panel Connections) (Rear Panel Connections)
BNC Cable
BNC
Receptacle
Split Ferrites*
*For E3640A/42A/44A models. **For E3641A/43A/45A models.
†For E3640A model, and see Table A-3 for other models.
‡For E3640A model, and see Table A-2 for other models.