4.3 TRACKING ADJUSTMENTS
Set locking toggle
switch
S202,
to
TRACKING. Set
output
voltage
of
Source A
to
approx-
imately
15
volts by means
of
the
DVM
and record
to
within
2MV. (For example 15.037V).
WITHOUT CHANGING THE SETTING OF SOURCE A OUTPUT VOLTAGE CONTROL transfer
DVM
to Source
B.
Adjust
R234
to
obtain the original recorded.
"A"
voltage within 2MV.
Voltages should now track through their entire range with
an
accuracy
of
0.1
% + 1 O
MV.
4.4 POWER SUPPLY MEASUREMENT TECHNIQUES
4.3.1
General
Power supply performance measurements require special techniques
to
insure cor-
rect results. The correct location
of
instrumentation leads is critical, since voltage
drops due to
contact
resistance and load current flow may lead
to
misleading results.
Four terminal network techniques as shown in Figure 1 must
be
employed
to
achieve
correct measurements.
In
addition
to
the equipment listed in 4.2.1, the following are required:
(1)
Adjustable
AC
input source (Variac) with provisions for accurately monitoring
the AC input voltage.
(2)
Oscilloscope with a bandwidth
of
not more than
10
MHz and a vertical sen-
sitivity
of
at
least 1 mV/cm.
4.4.2 Definitions
(1)
Line Regulation: The change in output voltage (constant voltage mode) or cur-
rent (constant current mode) when varying the
AC
input voltage through
its
specified range with a fixed load.
(2)
Load Regulation: The change in output voltage (constant voltage mode) or
current (constant current mode) with a specified step change in load
resistance.
(3)
Ripple: Any
AC
component that rides on the
DC
output
of
the supply. It is
usually synchronized with the input AC source frequency.
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