Agilent

34401 A Multimeter

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The Agilent 34401 A is a 6.5-digit multimeter. The Agilent 34401 A offers DC measurement accuracy of 0.0015% and AC accuracy of 0.06%. The Agilent 34401 A includes RS-232 and GPIB interfaces.^[1]

34401 A Multimeter — Inventory photo — Fig. 0134401 A MultimeterInventory photo^[2]

Power

45 - 440 Hz, 25va Max^[2]

Performance

0.02% + 400 nA^[4]

Optics

6.5 digits^[1]

What is it?

Applications

The Agilent 34401A is used in electronics testing for diagnosing circuits, verifying component values, and troubleshooting devices. In research and development laboratories, it supports experiments requiring precise data logging and measurement. Industrial applications include monitoring and testing equipment in manufacturing processes. The multimeter also serves as a teaching tool in educational settings for demonstrating electrical principles and measurement techniques.^[1]

What do the numbers mean?

Power & electrical26

~ Line: 45 - 440 Hz, 25va Max^[2]
Voltage Selector Positions: 100 / 120 / 220 / 240 V~^[2]
Fuse: 250v, 250ma^[2]
Voltage: 100 V ~ 120 V^[3]
Voltage: 200 V ~ 240 V^[3]
DC voltage accuracy: 0.0015%^[1]
AC voltage accuracy: 0.06%^[1]
DC voltage range: 100 mV to 1000 V^[4]
AC voltage range: 100 mV to 750 V^[4]
Frequency range: 1 Hz to 300 kHz^[4]
Diode testing range: forward voltage 2 V, current 1 mA^[4]
DC voltage accuracy (alternate): 0.0035% + 5 µV^[4]
AC voltage accuracy (alternate): 0.06% + 20 µV^[4]
Frequency accuracy: 0.01% + 5 mHz^[4]
Power supply: 100-240 V AC, 50/60 Hz^[4]
Line frequency (mains): 45 - 440 Hz, 25 VA max^[2]
Fuse rating: 250 V, 250 mA^[2]
DC voltage range: 100 mV to 1000 V with resolution 100 µV^[4]
AC voltage range: 100 mV to 750 V with resolution 100 µV^[4]
Frequency range: 1 Hz to 300 kHz with resolution 0.001 Hz^[4]
Diode testing: Forward voltage range 2 V, current range 1 mA^[4]
DC voltage accuracy: 0.0035% + 5 µV^[4]
AC voltage accuracy: 0.06% + 20 µV^[4]
Power supply (Micro Precision): 100-240 V AC, 50/60 Hz^[4]
Measurement capabilities: DC voltage, DC current, AC voltage, AC current, resistance, frequency, and diode testing^[4]
Line frequency range: 45-440 Hz^[2]

Optics & imaging5

Measurement resolution: 6.5 digits^[1]
Resolution: 6.5 digits^[1]
DC current range: 100 µA to 10 A with resolution 100 nA^[4]
AC current range: 100 µA to 10 A with resolution 100 nA^[4]
Resistance range: 100 Ω to 10 MΩ with resolution 100 mΩ^[4]

Performance5

DC current accuracy: 0.02% + 400 nA^[4]
AC current accuracy: 0.2% + 2 µA^[4]
Resistance accuracy: 0.05% + 20 mΩ^[4]
DC measurement accuracy: 0.0015%^[1]
AC measurement accuracy: 0.06%^[1]

Control & software1

Interfaces: RS-232 and GPIB^[1]

Configuration & options11

AC measurement type: True RMS^[1]
Maximum reading rate: 1000 readings per second in ASCII format^[1]
DC current range: 100 µA to 10 A^[4]
AC current range: 100 µA to 10 A^[4]
Resistance range: 100 Ω to 10 MΩ^[4]
Display: 5.5-digit LCD with refresh rate 5 readings/s^[4]
True RMS AC measurement: Yes^[1]
Max reading rate: 1000 readings per second (ASCII over GPIB)^[1]
Functions: More than a dozen functions accessible with one or two key presses^[1]
Display: 5.5-digit LCD with 5 readings/sec refresh^[4]
Max power: 25 VA^[2]

Vintage & configurations

Documented models & variants

Designation	Generation	Vintage	Changes	Source
Agilent/ HP 34401A Multimeter 6.5 Digit	—	—	Described as a 6.5-digit multimeter.	calright.com^[1]
AGILENT/HP 34401A 6 1/2 DIGIT MULTIMETER	—	—	Described as a 6 1/2 digit multimeter.	microprecision.com^[4]

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What does it need to run?

Site utility requirements, footprint, and infrastructure needed to install and operate this tool. Sourced from public records.

~ Line45 - 440 Hz, 25va Max^[2]
Voltage Selector Positions100 / 120 / 220 / 240 V~^[2]
Fuse250v, 250ma^[2]
Voltage100 V ~ 120 V^[3]
Voltage200 V ~ 240 V^[3]
DC voltage accuracy0.0015%^[1]
AC voltage accuracy0.06%^[1]
DC voltage range100 mV to 1000 V^[4]
AC voltage range100 mV to 750 V^[4]
Frequency range1 Hz to 300 kHz^[4]
Diode testing rangeforward voltage 2 V, current 1 mA^[4]
DC voltage accuracy (alternate)0.0035% + 5 µV^[4]
AC voltage accuracy (alternate)0.06% + 20 µV^[4]
Frequency accuracy0.01% + 5 mHz^[4]
Power supply100-240 V AC, 50/60 Hz^[4]
Line frequency (mains)45 - 440 Hz, 25 VA max^[2]
Fuse rating250 V, 250 mA^[2]
DC voltage range100 mV to 1000 V with resolution 100 µV^[4]
AC voltage range100 mV to 750 V with resolution 100 µV^[4]
Frequency range1 Hz to 300 kHz with resolution 0.001 Hz^[4]
Diode testingForward voltage range 2 V, current range 1 mA^[4]
DC voltage accuracy0.0035% + 5 µV^[4]
AC voltage accuracy0.06% + 20 µV^[4]
Power supply (Micro Precision)100-240 V AC, 50/60 Hz^[4]
Measurement capabilitiesDC voltage, DC current, AC voltage, AC current, resistance, frequency, and diode testing^[4]
Line frequency range45-440 Hz^[2]

Where are the manuals?

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Not publicly documented

Field notes

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Frequently asked questions

What is the resolution of the Agilent 34401 A?

The Agilent 34401 A provides 6.5-digit resolution.^[1]

What is the DC voltage accuracy?

The DC measurement accuracy is 0.0015%.^[1]

What interfaces does the multimeter support?

The multimeter includes RS-232 and GPIB standard interfaces.^[1]^[4]

What is the maximum reading rate?

The instrument can achieve up to 1000 readings per second in ASCII format across the GPIB bus.^[1]

What are the DC voltage measurement ranges?

The DC voltage range is 100 mV to 1000 V with a resolution of 100 µV.^[4]

Not publicly documented

The following facts about the 34401 A Multimeter are absent from this record as of this revision. First-hand knowledge or a citation closes a gap; every submission is reviewed before publication.

No publicly documented production dates or lifecycle milestones (introduction, end of production, EOL) for the 34401 A Multimeter are on record.
Answerable by: OEM historical records or a trade-press announcement
The control-system platform and OS era of the 34401 A Multimeter are not on record.
Answerable by: an engineer who operated it or OEM installation records
No publicly documented failure modes or field errata for the 34401 A Multimeter are on record.
Answerable by: a field service engineer, process engineer, or maintenance technician
The process node or technology generation of the 34401 A Multimeter is not on record.
Answerable by: an OEM datasheet or a fab qualification report
No publicly documented compatible parts, consumables, or accessories for the 34401 A Multimeter are on record.
Answerable by: an OEM parts catalog or a service engineer

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Sources & citations

Sources (5)Every fact above is drawn from these public sources

[1]calright.com — calright.comcalright.com
[2]Inventory photo
[3]Inventory photo
[4]microprecision.com — microprecision.commicroprecision.com
[5]Reading signal from agilent 34401 A multimeter and printing on the serial - General Guidance - Arduino Forum — forum.arduino.ccforum.arduino.cc