Front Panel Operation
Using the 5725A Amplifier
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4-47
4-44. Using the 5725A Amplifier
The 5725A Amplifier increases the current and voltage bandwidth, and drive capability
of the 5500A Calibrator. The 5725A Amplifier has separate voltage boost and current
boost amplifiers, however, only one boost function can be used at any one time. When
operated in dual output modes such as ac power, the 5725A Amplifier can supply one
output, while the 5500A Calibrator supplies the other output.
In the voltage boost mode, the 5725A output appears on the 5500A Calibrator NORMAL
terminals. In the current boost mode, the 5725A output appears on the 5725A
CURRENT OUTPUT terminals. You can also redirect 5500A current to the 5725A
output terminals; 0 - 2.2 A dc, and 300 µA - 2.2 A ac. The Output Display on the 5500A
always shows the actual output of the amplifier, not the excitation output of the 5500A.
Rules of Operation
• Whenever the 5500A Calibrator front panel B key annunciator is on, either the
5725A voltage boost amplifier or current boost amplifier is in use. The 5725A
Amplifier front panel indicators identify which amplifier is operating.
• If the 5725A Current Amplifier indicator is on, while the 5500A B annunciator is
off, 5500A current is being directed to the 5725A terminals. During this condition,
both the 5725A voltage boost and current boost amplifiers are disabled.
• When sourcing current, the output softkey choice AUX (5500A) or BOOST (5725A)
takes precedence over the Source Preference softkey and the front panel B key.
Exception: When the selected current cannot be sourced by the 5500A (e.g., 10 A,
15 kHz), the output automatically switches to BOOST and displays error 540 in the
Control Display (Current OUTPUT moved to 5725A).
• The Source Preference softkey in the SETUP menu chooses the 5500A Calibrator or
5725A Amplifier when either can source the selected output. The B key is a
temporary Source Preference selection. Toggling B on sets the Source Preference
to the 5725A. Toggling B off sets the Source Preference to the 5500A. Pressing
R reestablishes the default Source Preference stored in the non-volatile memory.
• Any current or voltage combination that is outside the capabilities of the 5500A
Calibrator but within the capabilities of the 5725A Amplifier, will automatically
activate the 5725A Amplifier output.
Examples
• Selecting a 5725A Amplifier boost current between 1.5 - 2.19999 A:
Enter the desired current.
Select boost with the OUTPUT softkey.
Verify source preference is 5725.
Verify the B annunciator is on.
The boost current appears on the 5725A CURRENT OUTPUT terminals.
• Selecting a 5725A Amplifier boost current > 2.2 A:
Enter the desired current.
Select boost with the OUTPUT softkey.
(Source preference unimportant)
Verify the B annunciator is on (and cannot be toggled off)
The boost current appears on the 5725A CURRENT OUTPUT terminals.