Verification and Calibration Appendix B
CV Source Effect
Test category = performance
This test measures the change in output voltage that results from a change in AC line voltage from the minimum to maximum value within the line voltage specifications.
1Turn off the power supply and connect the ac power line through a variable voltage transformer.
2Connect a DVM and an electronic load as shown in figure A. Set the variable voltage transformer to nominal line voltage.
3Turn on the power supply and program the output current to its maximum programmable value (Imax) and the output voltage to its
4Set the electronic load for the output’s
5Adjust the transformer to the
6Record the output voltage reading from the DVM.
7Adjust the transformer to the
8Record the output voltage reading on the DVM. The difference between the DVM reading in steps 6 and 8 is the source effect, which should not exceed the value listed in the test record card for the appropriate model under CV Source Effect.
CV Noise
Test category = performance
Periodic and random deviations in the output combine to produce a residual AC voltage superimposed on the DC output voltage. This residual voltage is specified as the rms or
1Turn off the power supply and connect the load resistor, differential amplifier, and an oscilloscope (ac coupled) to the output as shown in figure C. Use the indicated load resistor for 750W outputs; use the indicated load resistor for 1500W outputs.
2As shown in the diagram, use two BNC cables to connect the differential amplifier to the + and − output terminals. Each cable should be terminated by a 50 Ω resistor. The shields of the two
BNC cables should be connected together. Connect the output of the differential amplifier to the oscilloscope with a 50 Ω termination at the input of the oscilloscope.
3Set the differential amplifier to multiply by ten, divide by one, and 1 Megohm input resistance. The positive and negative inputs of the differential amplifier should be set to AC coupling. Set the oscilloscope’s time base to 5 ms/div, and the vertical scale to 10 mV/div. Turn the bandwidth limit on (usually 20 or 30 MHz), and set the sampling mode to peak detect.
Series N5700 User’s Guide | 97 |