
Theory of Operation
Overall Functional Description
4
4-5
•
11A DC Function:
The 11A dc function is implemented with a transconductance (voltage in/current
out) amplifier with a gain of -5. If the 5700A outputs -2V into the 5725A, the 5725A
output is 10A. (This is transparent to the user.) The output range is 0 to 11A. The
5725A delivers amplified current to either the front or rear panel binding posts of the
5725A, depending on an internal hardware setup. Reconfiguration requires removing
the covers, and is described in Section 6.
•
11A AC Function
The 11A ac function is similar to the 11A dc function. The frequency range is 40 Hz
to 10 kHz. The output range is 1 to 11A rms. As in the dc current function, all
outputs from the 5725A either go through the front or rear panel of the 5725A. Input
to the 5725A comes from the 5700A Oscillator assembly.
1100V AC Range Functional Description
4-3.
The 5700A Oscillator assembly generates the driving ac voltage, then sends it to the
5725A Power Amplifier for amplification. The 5725A returns an attenuated feedback
voltage for output correction. The final output voltage is kept accurate by the high
voltage sense amplifier and a real-time, software-controlled feedback loop within the
5700A, incorporating a 5700A ac/dc thermal rms converter. The 5700A Oscillator, DAC
(digital-to-analog converter), and ac/dc thermal rms converter work together with the
5725A Power Amplifier and high voltage attenuator circuits to produce the desired
output.
Active assemblies in the 5725A ac voltage function are as follows:
•
In the 5700A: CPU, DAC, Oscillator, Oscillator Control, High-Resolution
Oscillator, Switch Matrix, Motherboard, Rear Panel assemblies.
•
In the 5725A: CPU, High Voltage Amplifier, High Voltage Sense, Signal
Transformer, Power Supply, Digital, and Interconnect assemblies.
When an ac voltage in the 220 to 1100V range is selected, the 5700A calls the 5725A
amplifier and leaves its own high voltage amplifier dormant. The 5725A takes over the
1100V ac range automatically. The 5725A produces ac voltage in the following
sequence:
1.
The 5700A sets the Oscillator assembly to the proper frequency and amplitude. The
5700A sets the initial amplitude using an 8-bit resistive hybrid dac located on the
Oscillator amplifier assembly, yielding an Oscillator output accuracy of about 0.5%.
2.
Next, the 5725A Power Amplifier amplifies this signal by -100 and returns an
accurately attenuated signal to the 5700A.
3.
The 5700A thermal sensor and adc (analog-to-digital converter) monitoring system
fine tune the Oscillator amplitude. The DAC assembly output is switched directly to
the Oscillator assembly, controlling the dac output amplitude. AC voltage calibration
constants stored in the 5725A determine the 5700A DAC voltage setting.
Summary of Contents for 5725A
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Page 62: ...5725A Instruction Manual 4 4 Figure 4 1 5725A Overall Block Diagram...
Page 78: ...5725A Instruction Manual 4 20 aq20f eps Figure 4 3 Current Amplifier Assembly Block Diagram...
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Page 132: ...5725A Instruction Manual 8 6 aq24f tif Figure 8 1 Final Assembly...
Page 133: ...List of Replaceable Parts 8 8 7 aq25f tif Figure 8 1 Final Assembly cont...
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Page 139: ...List of Replaceable Parts 8 8 13 aq31f tif Figure 8 1 Final Assembly cont...
Page 141: ...List of Replaceable Parts 8 8 15 5725A 1611 aq36f eps Figure 8 2 A1 Interconnect PCA...
Page 145: ...List of Replaceable Parts 8 8 19 5725A 1650 aq37f eps Figure 8 3 A2 Current Amplifier PCA...
Page 149: ...List of Replaceable Parts 8 8 23 5725A 1661 aq38f eps Figure 8 4 A3 High Voltage Amplifier PCA...
Page 153: ...List of Replaceable Parts 8 8 27 5725A 1631 aq39f eps Figure 8 5 A4 Power Supply PCA...
Page 155: ...List of Replaceable Parts 8 8 29 5725A 1650 aq40f eps Figure 8 6 A5 Digital PCA...
Page 159: ...List of Replaceable Parts 8 8 33 5725A 1601 aq41f eps Figure 8 7 A6 High Voltage Sense PCA...
Page 161: ...List of Replaceable Parts 8 8 35 aq32f tif Figure 8 8 A12 Transformer Enclosure Assembly...
Page 162: ...5725A Instruction Manual 8 36 aq33f tif Figure 8 8 A12 Transformer Enclosure Assembly cont...
Page 163: ...List of Replaceable Parts 8 8 37 aq34f tif Figure 8 8 A12 Transformer Enclosure Assembly cont...
Page 164: ...5725A Instruction Manual 8 38 aq35f tif Figure 8 8 A12 Transformer Enclosure Assembly cont...
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Page 169: ...Schematic Diagrams 9 3 9 Figure 9 1 A1 Interconnect PCA 5725A 1611 aq48f eps...
Page 170: ...5725A Instruction Manual 9 4 Figure 9 1 A1 Interconnect PCA cont...
Page 171: ...Schematic Diagrams 9 5 9 Figure 9 1 A1 Interconnect PCA cont...
Page 172: ...5725A Instruction Manual 9 6 Figure 9 2 A2 Current Amplifier PCA 5725A 1650 aq52f eps...
Page 173: ...Schematic Diagrams 9 7 9 Figure 9 2 A2 Current Amplifier PCA cont...
Page 174: ...5725A Instruction Manual 9 8 Figure 9 2 A2 Current Amplifier PCA cont...
Page 175: ...Schematic Diagrams 9 9 9 Figure 9 2 A2 Current Amplifier PCA cont...
Page 176: ...5725A Instruction Manual 9 10 Figure 9 3 A3 High Voltage Amplifier PCA 5725A 1661 aq56f eps...
Page 177: ...Schematic Diagrams 9 11 9 Figure 9 3 A3 High Voltage Amplifier PCA cont...
Page 178: ...5725A Instruction Manual 9 12 Figure 9 3 A3 High Voltage Amplifier PCA cont...
Page 179: ...Schematic Diagrams 9 13 9 Figure 9 4 A4 Power Supply PCA 5725A 1631 aq59f eps...
Page 180: ...5725A Instruction Manual 9 14 Figure 9 4 A4 Power Supply PCA cont...
Page 181: ...Schematic Diagrams 9 15 9 Figure 9 4 A4 Power Supply PCA cont...
Page 183: ...Schematic Diagrams 9 17 9 Figure 9 5 A5 Digital PCA cont...
Page 185: ...Schematic Diagrams 9 19 9 Figure 9 6 A6 High Voltage Sense PCA cont...
Page 186: ...5725A Instruction Manual 9 20 Figure 9 6 A6 High Voltage Sense PCA cont...
Page 187: ...Schematic Diagrams 9 21 9 Figure 9 6 A6 High Voltage Sense PCA cont...
Page 188: ...5725A Instruction Manual 9 22 Figure 9 6 A6 High Voltage Sense PCA cont...
Page 189: ...Schematic Diagrams 9 9 23 aq45f eps Figure 9 7 A12 Transformer Enclosure Assembly...
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