Filter
Top Products
104
supply, connect both leads to either the positive or the negative sensing terminals, whichever is grounded to
chassis.
Signals on the face of the CRT as a result of either of these tests are indicative of shortcomings in the
measurement setup. The most likely causes of these defects and proper corrective measures are discussed
further under CV PARD (Ripple and Noise).
Connect AC Voltmeter Properly.
It is important that the ac voltmeter be connected as close as possible to the input ac terminals of the power
supply so that its indication will be a valid measurement of the power supply input, without any error
introduced by the IR drop present in the leads connecting the power supply input to the ac line voltage source.
Use an Auto-Transformer of Adequate Current Rating.
If this precaution is not followed, the input ac voltage presented at the power supply may be severely distorted,
and the rectifying and regulating circuits within the power supply may operate improperly.
Do Not Use an AC Input Line Regulator
Such regulators tend to increase the impedance of the ac input as explained previously.
Further precautions necessary for the proper measurement of specific power supply specifications are given as
required in the following paragraphs.
CV Source Effect (Line Regulation)
Definition: Formerly known as line regulation, source effect is the change
∆
E
OUT
in the steady state value of dc
output voltage due to a change in ac input voltage over the specified range from low line (e. g., 104 volts) to
high line (e. g., 127 volts) or from high line to low line.
Actual measurement is accomplished by turning the variable autotransformer (Figure 70) through the specified
range from low line to high line and noting the change in the reading of the digital voltmeter or differential
voltmeter connected to the output terminals of the supply. The measurement is performed with all other
parameters maintained constant. The power supply will perform within its source effect specifications at any
rated output voltage combined with any rated output current; the most severe test normally involves measuring
source effect at maximum output voltage combined with maximum output current.
Notice that the line regulation specification for Agilent power supplies is not prefixed by “ ± ”. Thus the line
regulation specification sets a limit on the total excursion of the output voltage resulting from the total input ac
change from low line to high line, thereby allowing only one-half the output deviation of a “ ± ” specification.
CV Load Effect (Load Regulation)
Definition: Formerly known as load regulation, load effect is the change
∆
E
OUT
in the steady state value of dc
output voltage due to a change in load resistance from open circuit to a value that yields maximum rated output
current (or vice versa).
Load effect is measured by closing or opening the switch in Figure 70 and noting the resulting static change
∆E
OUT
in the output voltage on the digital voltmeter or differential voltmeter connected to the output terminals.