Keysight E3631A, Service Manual

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Calibration Procedures 3
Keysight E3631A Service Guide 55
General measurement techniques
To achieve best results when measuring load regulation, peak-to-peak voltage,
and transient response time of the power supply, measuring devices must be
connected through the hole in the neck of the binding post at (A) while the load
resistor is plugged into the front of the output terminals at (B). A measurement
made across the load includes the impedance of the leads to the load. The
impedance of the load leads can easily be several orders of the magnitude greater
than the power supply impedance and thus invalidate the measurement. To avoid
mutual coupling effects, each measuring device must be connected directly to the
output terminals by separate pairs of leads.
Figure 3-2 Front panel terminal connection
Electronic load
Many of the test procedures require the use of a variable load resistor capable of
dissipating the required power. Using a variable load resistor requires that
switches be used to connect, disconnect, and short the load resistor. An
electronic load, if available, can be used in place of a variable load resistor and
switches. The electronic load is considerably easier to use than load resistors. It
eliminates the need for connecting resistors or rheostats in parallel to handle
power, it is much more stable than carbon-pile load, and it makes easy work of
switching between load conditions as is required for the load regulation and load
transient response tests. Substitution of the electronic load requires minor
changes to the test procedures in this chapter.