The Keysight/Agilent/HP 3456A is a 6.5-digit digital voltmeter engineered for precision DC and AC voltage measurement, resistance characterization, and ratio calculations in benchtop and automated test systems. Its microprocessor-based, fully guarded architecture delivers high accuracy and stability across demanding calibration and metrology environments.
Technical Specifications
Measurement Capabilities
• DC Voltage: 5 ranges, 0.1 V to 1000 V full-scale; 100 nanovolt resolution
• True RMS AC Voltage: 4 ranges, 1 µV to 700 V full-scale; 1 µV resolution
• Resistance: 100 µΩ to 1.0 GΩ (2-wire) or 1 mΩ to 1 GΩ (4-wire); offset-compensated ohms (OCO) available
• Ratio measurements and math functions: scale, limit test, null, percent error, dB, dBm, thermistor conversion, statistics
AC Performance
• Frequency range: 20 Hz to 250 kHz
• Crest factor: >7 at full scale
• Normal mode rejection (NMR): 90 dB @ 1 PLC, 60 dB @ >1 PLC
• Common mode rejection (CMRR): 140 dB @ 1 PLC or >1 PLC
• Filter mode rejection: >60 dB @ 50 Hz or 60 Hz
Accuracy and Stability
• DC voltage (10 V range, 24 hours @ 23°C ± 1°C): ±0.0008% of reading + 2 counts
• AC voltage: 0.05% best accuracy
• Temperature coefficient (DC, 6.5 digit): ±(0.008% + 15 counts)/°C
• Temperature coefficient (AC, filter/auto-zero ON): ±(0.05% + 2 counts)/°C
Measurement Speed
• Up to 330 readings/second (3.5–4.5 digits)
• 48 readings/second at 6.5-digit resolution
• Selectable integration time up to 100 power line cycles
• Periodic measurement mode: one reading every fifteen minutes
Input Characteristics
• DC input impedance: >10 GΩ
• AC input capacitance: 10 GΩ DC) minimizes loading errors
• Noise rejection optimized for 50 Hz and 60 Hz line environments
• Programmable settling and integration windows for speed/accuracy trade-off
– Typical Applications
Precision DC voltage and resistance calibration; transfer standard measurements; AC voltage characterization in frequency-selective environments; thermistor-based temperature monitoring; automated production test systems requiring GPIB control.
– Compatibility & Integration
IEEE 488 interface enables integration into automated test stations. Operates on 100/120/220/240 V ±5–10%, 48–400 Hz, consuming 46–60 VA.
