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b. Apply input power to supply.
c. With no load connected, set output voltage of
supply to any value desired within adjustment span.
This output voltage can be used for ail remaining con¬
stant voltage tests.
d. With supply off, connect full load resistance
across + and - output terminals of supply (see Para¬
graph 5-11).
e. Reconnect input power to supply. Voltmeter
should read output voltage set in Step c (within tol¬
erances of load resistor and meter).
5-17 Current. To ensure that the supply will furnish
the maximum rated output current, proceed as follows:
a. Connect test setup shown In Figure 5-2. Select
load and current sampling resistor values according to
Paragraphs 5-11 and 5-13.
b. Apply input power to supply and adjust Rl
until digital voltmeter indicates a voltage drop which
is proportional to the maximum rated output current,
5-18 Load Regulation
Definition: The change AE out
the static
value of DC output voltage resulting from a
change in load resistance from open circuit to a
value which yields maximum rated output current
(or vice versa).
5-19 To check the constant voltage load regulation,
proceed as follows:
a. Connect full load resistance across rear output
terminals (Paragraph 5-11).
b. Connect digital voltmeter across ±S terminals.
c. 'Turn on supply and obtain desired output
voltage. Record voltage read on voltmeter.
d. Disconnect load resistance.
e.
Reading
on
digital voltmeter should not vary
.
from reading recorded in step c by more than 0.01 % or
ImV, whichever is greater.
5-20Line Regulation
Definition: The change, AE qut f
value of DC output voltage resulting from a change
in AC input voltage over the specified range from
low line (usually 104 Volts) to high line (usually
127 Volts), or from high line to low line.
5-21 To test the line regulation, proceed as follows:
j;
a. Connect variable auto transformer between
|
input power source and power supply power input
|
terminals.
b. Connect load resistance and digital voltmeter
across output of supply.
c. Adjust variable auto transformer for low line
input.
d. Turn on setup. Read and record output volt¬
age on digital voltmeter.
e. Adjust variable auto transformer for high line
input.
f. Reading on digital voltmeter should not vary
from reading recorded in step d by more than 0.01% or
ImV, whichever is greater.
5-22 Ripple and Noise
Definition: The residual AC voltage which is
superimposed on the DC output of a regulated
power supply, Ripple and noise may be specified
and measured in terms of its RMS peak-to-peak
<
value.
<
5-23
Ripple
and noise measurement can be made at
any input AC line voltage combined with any DC out- j
put voltage and load current within rating.
|
5-24 Figure 5-3A shows an incorrect method of mea- (
suring p-p ripple. Note that a continuous ground loop !
exists from the third wire of the input power cord of
|
5-3
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