Specifications 8
Agilent U1251A/U1252A User’s and Service Guide 151
Electrical Specifications
DC Specifications
Table 7-1 DC Accuracy ± (% of reading + Number of Least Significant Digit)
Function Range Resolution
Test Current/
Burden Voltage
Accuracy
U1251A U1252A
Voltage
[1]
50.000 mV 0.001 mV - 0.05 + 50
[2]
0.05 + 50
[2]
500.00 mV 0.01 mV -
0.03 + 5
0.025 + 5
1000.0 mV 0.1 mV -
5.0000 V 0.0001 V -
50.000 V 0.001 V -
500.00 V 0.01 V - 0.03 + 5
1000.0 V 0.1 V -
Notes for DC voltage specifications:
1 Input impedance: >1GΩ for 50 mV to 1000 mV ranges. For U1251A, input impedance is 10 MΩ (nominal) for 5 V to 1000 V
ranges. For U1252A, input impedance is 10 MΩ (nominal) in parallel with 1.1 MΩ at dual display.
2 The accuracy could be 0.05 % +10 for U1251A and 0.05 % + 5 for U1252A. Always use the Null function to zero out the
thermal effect before measuring the signal.
Function Range Resolution
Test Current/
Burden Voltage
Accuracy
U1251A U1252A
Resistance
500.00 Ω
[3]
0.01 Ω 1.04 mA 0.08 + 10 0.05 + 10
5.0000 kΩ
[3]
0.0001 kΩ 416 µA
0.08 + 5
0.05 + 5
50.000 kΩ 0.001 kΩ 41.2 µA
500.00 kΩ 0.01 kΩ 4.12 µA
5.0000 MΩ 0.0001 MΩ 375 nA 0.2 + 5 0.15 + 5
50.000 MΩ
[4]
0.001 MΩ 187 nA 1 + 10 1 + 5
500.00 MΩ
[4]
0.01 MΩ 187 nA -
3 + 10 < 200MΩ/
8 + 10 > 200MΩ
500.00 nS
[5]
0.01 nS 187 nA 1 + 20 1 + 10
Notes for resistance specifications:
3 The accuracy of 500 Ω and 5 kΩ is specified after Null function, which is used to subtract the test lead resistance and the
thermal effect.
4 For the range of 50/500 MΩ, the R.H. is specified for < 60 %.
5 The accuracy is specified for < 50 nS and after Null function with open test lead.
