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2 - General Information
22
NOTE: Operating the dc source beyond its output ratings may cause the output to become unregulated.
This is indicated by the UNR annunciator on the front panel. The output may also become
unregulated if the ac line voltage drops below the minimum rating specified in Appendix A.
Programmable Output Resistance
Programmable output resistance lets you emulate the internal resistance of a cell phone battery, which
causes the voltage at the phone to drop as the phone draws more current. Different types of phone
batteries have different internal resistance values, which typically fall in a range of several hundred
milliohms. The internal resistance of a phone battery also changes with age and the number of times the
battery is recharged. Therefore, to evaluate the performance of a cell phone using various battery
characteristics, use this feature to specify a desired battery resistance.
Alternatively, programmable output resistance can be used to keep the voltage at the phone terminals as
constant as possible. In this case, you may program a negative output resistance. This compensates for
any additional voltage drop in the load leads between the remote sense points and the phone terminals
(see Figure 3-4). In phone test fixtures, the cell phone terminals may be located up to 50 centimeters
away from the connector where the remote sense terminals of the dc source are connected. This results in
a small voltage drop in the wires between the remote sense terminals and the phone terminals. If it is
critical that the steady-state voltage at the phone terminals be equal to the programmed voltage of the dc
source, a small negative output resistance can be programmed to compensate for this voltage drop.
Output 2 Characteristic
As shown in the following figure, Agilent 66319B/D units have a second output rated at 12 V and 1.5A.
The second output has all of the primary programmable features as the main output, with the exception of
the waveform measurement capability, the open sense lead detect capability, overvoltage protection, and
low current range.
Output
Voltage
Output
Current
1.5A
+12V
0
+
-
3.0A
Peak Current
capability for up
to 1 ms shown
by dotted lines
Figure 2-2. Output 2 Characteristic
Tables A-1 through A-3 document the specifications and supplemental characteristics of the Agilent dc
sources documented in this manual.