Verification and Calibration Appendix B
Measurement Techniques
Electronic Load
Many of the test procedures require the use of a variable load capable of dissipating the required power. If a variable resistor is used, switches should be used to either; connect, disconnect, or short the load resistor. For most tests, an electronic load can be used. The electronic load is considerably easier to use than load resistors, but it may not be fast enough to test transient recovery time and may be too noisy for the noise (PARD) tests.
Fixed load resistors may be used in place of a variable load, with minor changes to the test procedures. Also, if computer controlled test setups are used, the relatively slow (compared to computers and system voltmeters) settling times and slew rates of the power supply may have to be taken into account. "Wait" statements can be used in the test program if the test system is faster than the power supply.
Current-Monitoring Resistor
The
Test Set-up
The following figure illustrates the test
Power Supply
+S +LS
Power Supply |
| Power Supply |
+S +LS |
| +S +LS |
+
DC voltmeter,
scope, or
rms voltmeter
A. | + |
|
|
|
| ||
Electronic load | |||
| or resistor | ||
|
|
|
|
DC voltmeter,+ | Current | |
scope, or | ||
shunt | ||
rms voltmeter | ||
| ||
B. | + | |
Electronic load | ||
| or resistor |
Load
Resistor
5050
BNCBNC
+Differential amplifier
output
BNC
50ohm
termination
C.
input
Scope or rms voltmeter
Series N5700 User’s Guide | 95 |