8Hintsfor Making Better Digital Multimeter Measurements

Application Note

2

The simplest way to remove errorscaused by connections and wiresis to make a null measurement.For a DCV or resistance measure-ment, select the appropriate rangefor the measurement, then connectthe probes together and wait for ameasurement—it should be prettyclose to zero—then press the nullbutton. Subsequent readings willsubtract the null measurement.Null measurements tend to workwell for both DC and resistancemeasurements. Unfortunately,this technique does not work forAC measurements. AC convertersare not designed to work at thelowest part of the range; theAgilent 34401A digital multime-ter’s analog converter is not specified below 10% of full-scale.Agilent’s 34410A and 34411A multimeters use a digital techniqueand can measure down to 1% offull scale, but they are not designedto measure a short.

Connections

When you make connections withdissimilar metals, a thermocouplejunction is formed. A thermocou-ple junction produces a voltagethat changes with temperature.The voltage created is small, but itneeds to be addressed if you aremeasuring small voltages or yoursystem has many connections.Junctions to consider are at theDUT, at relays (multiplexers), and at your multimeter. Using copper-to-copper junctions willhelp minimize offsets.

When you make resistance meas-urements, you can use offset compensation to measure any offset voltage and remove theerror. Figure 1 illustrates the two measurements used in offset-compensated measurements, one with the current source and a second without the currentsource. Subtracting the secondmeasurement from the first anddividing by the known currentsource will give you the actualresistance. Since two measure-ments are made per reading,reading speed will be reduced, butaccuracy will be improved. Offsetcompensation can be used in bothtwo- and four-wire measurements.

1Avoid measurement

errors caused by

connections,

test leads or wires

Multimeter

R iV VEMF= +

Ri

VEMF

V

+

--

Multimeter

V VEMF=

Ri

VEMF

V+

--

Figure 1

Offset compensation using two measurements. The first measurement is a standard ohm measurement; the second one measures the offset generated by thermal EMF. The meter reading is the differencebetween the two measurements divided by the known current source.

Hint

3

Internal multimeter offsets

Autozero is used to removesources of error within the multimeter. When autozero isenabled, the multimeter internallydisconnects the input signal following each measurement and takes a zero reading. It thensubtracts the zero reading fromthe preceding reading. This prevents offset voltages presenton the multimeter’s input circuitryfrom affecting measurementaccuracy. Autozero is alwaysenabled for four-wire measure-ments, but you can disable it for two-wire measurements toincrease measurement speed.

When autozero is disabled, the multimeter takes one zeroreading and subtracts it from all subsequent measurements. It takes a new zero reading eachtime you change the function,range, or integration time.

R iVunknown

Display:

Multimeter

= /

RiV unknown=

R lead

i = 0

i = 0

R lead

R lead

R lead

Runknown Vi +

--

Figure 2

No current flows through the voltagesense leads. The multimeter divides the measured voltage by the known current to determine theunknown resistance.

Leads

The four-wire ohms method is the most accurate way to measuresmall resistances. Test-lead resist-ances and contact resistances areautomatically reduced using thismethod. The connections for four-wire resistance measurements areshown in Figure 2. Using a knowncurrent source and measuring thevoltage produced by the resistor,the unknown resistance can becalculated. The additional set ofleads carries the current to theunknown resistor, which creates a voltage that can be measuredthrough the voltage sense leads.No current flows through the voltage sense leads, so no addi-tional voltage drop is created inthese leads.

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4

Settling time effects

A capacitance in parallel with aresistor causes settling time errorsafter an initial connection andafter a range change. Modern multimeters insert a trigger delayto allow time for the measurementto settle. The length of the triggerdelay is dependent on the selectedfunction and range. While thesedelays are adequate for resistancemeasurements with less than afew hundred pF of combinedcable and device capacitance, the default delays may not beadequate if the resistor has a parallel capacitance or you aremeasuring resistances above100 kΩ. Settling due to RC timeconstant effects can be quite long. Some precision resistorsand multi-function calibratorsuse parallel capacitors (1000 pFto 100 µF ) with high resistor values to filter out noise currentsinjected by their internal circuitry.Non-ideal capacitances due todielectric absorption (soak) effectsin cables and other devices mayincrease the RC time constantand require much longer settlingtimes. You may need to increasethe trigger delay before making ameasurement in these situations.

Offset compensation when acapacitance is present

If a resistor has a parallel capaci-tance, it may be desirable to turnoff offset compensation. Whenoffset compensation makes a sec-ond reading without the currentsource on, it will measure any

voltage offsets. However, if adevice has a long settling time, it can create an erroneous offsetmeasurement. The multimeterwill apply the same trigger delayto the offset measurement in anattempt to avoid settling timeissues. Increasing the trigger delayso the device is fully settled isanother solution.

Connections in high-resistancemeasurements

When you are measuring largeresistances, significant errors canbe caused by insulation resistanceand surface contamination. Take the necessary precautionsto maintain a “clean” high-resistance system. Test leads andfixtures are susceptible to leakagecaused by moisture absorption in insulating materials and“dirty” surface films. Nylon andPVC are relatively poor insulators(109 ohms) compared to PTFETeflon insulators (1013 ohms).Leakage from nylon or PVC insu-lators can easily contribute a 0.1%error if you measure a 1MΩresistance in humid conditions.

Measuring

large resistances

2Hint

5

Many signals contain both an ACand a DC component. For exam-ple, an asymmetric square wavecontains both components. Manyaudio signals contain a DC offsetcreated by the DC bias currentthat drives the output transistors.In some cases it is desirable tomeasure both the DC + AC voltage,while in others, you may wantjust the AC component. For thisaudio example, the amplifier gain would compare the input ACvoltage to the output AC voltage.

Most modern multimeters use aDC blocking capacitor in front ofthe AC RMS converter. Blockingthe DC voltage allows the multi-meter to measure just the ACvalue. More importantly, the multimeter can scale the AC signal for the best possible meas-urement. For example, whenmeasuring the AC ripple of apower supply, the multimeterblocks high-level DC signal butcan amplify the AC signal byselecting the range based on just the AC component.

To make the most accurateAC+DC measurement, the twocomponents should be measuredindependently. The multimetercan be configured to make thebest possible DC measurementusing the proper range and

integration to reject the AC component. When making the AC measurement, select theappropriate range for just the AC component. You can computethe total AC+DC RMS value with the following formula:

Agilent’s new 34410A and 34411Ause a DC blocking capacitor whenthey make an AC voltage meas-urement. The AC measurement ismade using a digital techniquethat provides faster settling timesand can handle higher crest factors that are common when

you measure pulse trains. Whenyou measure pulses, make surethey do not contain frequenciesgreater than the multimeter’sbandwidth. The 34410A and34411A can measure AC signalsup to 300 kHz. If the AC compo-nent has most of its frequencycontent below 8 kHz, the 34410Aor 34411A can accurately measureboth the DC and AC componentusing the DC function with peakdetect. For higher-frequency signals,you can measure the AC compo-nent separately and use the formula to compute the AC+DCmeasurement.

Making an

AC measurement

with a DC offset

True RMSAC+DC = SQRT( AC2 + DC2 )

1 VDC

-1 VDC

1 ms

0 VDC

5 VDC

0 VDC

5 VDC

Figure 3

An asymmetric square wave waveform with a duty cycle that is not equal to 50%. A multimeter can be used to measure both the AC and the DC component.

Figure 4

The output of a DC power supply has some ripple AC noise. The power supply output can be characterized by measuring the AC and DC component.

Figure 5

A pulse train has both a DC and an AC component. When you measure pulses, make sure you do not exceed the multimeter’s bandwidth.

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3Hint

6

Most modern multimeters can measure AC voltages with frequencies as low as 20 Hz.Some applications require measuring signals with evenlower frequencies. To make these measurements you willneed to select an appropriatemultimeter and configure itproperly. A few examples:

Agilent’s 34410A and 34411A multimeters use a digital samplingmethod to make true RMS meas-urements that are specified tomeasure down to 3 Hz. Using adigital method improves settlingtime to 2.5 s for the slow filter. To make the best measurement,you need to take a few precautions:

1. It is important to set the correct AC filter. The filtersmoothes the output of thetrue RMS converter. For frequencies less than 20 Hz,the correct setting is LOW. At the LOW filter setting, a 2.5-second delay is insertedto ensure the multimeter is settled. Use theVOLTage:AC:BANDwidth MINcommand to set the low filter.

2. If you know the maximumlevel for the signal you aremeasuring, setting a manualrange will help speed meas-urement time. The longer settling times required for

each low-frequency measure-ment can slow the auto-ranging feature significantly.We recommend you set amanual range.

3. The 34401A uses a DC block-ing capacitor to prevent DCsignals from being measuredby the AC RMS converter. Thisallows the multimeter to usethe best range for measuringthe AC component. Whenmeasuring a source with highoutput impedance, ample timeis necessary to ensure the blocking capacitor is settled.Settling time is not affected by the frequency of the AC signal, but rather by anychange in the DC signal.

Measuring

low-frequency

AC signals

with a digital

multimeter

4Hint

7

The Agilent 3458A has threemethods for measuring AC RMSvoltages; its synchronously sub-sampled mode can measuredown to 1 Hz. To configure themultimeter to measure low frequencies:

1. Select the synchronously sub-sampled mode: SETACV: SYNC

2. When you are using synchro-nous sub-sampling, the inputsignal is DC-coupled for boththe ACV and ACDCV function.In the ACV function, the DCcomponents are mathematicallysubtracted from the reading.This is important to considersince the combined AC and DCvoltage levels may cause anoverload condition, even thoughthe AC voltage alone normallywould not.

3. Selecting the proper range willspeed measurements, since theauto-range feature can causedelays when you measure low-frequency signals.

4. In order to sample the wave-form, the multimeter needs to determine the period of the signal. Use the ACBANDcommand to determine time-

out values. If you don’t use the ACBAND command, themultimeter could timeoutbefore the waveform repeats.

5. The synchronously sub-sampledmode uses the LEVEL trigger tosync to the signal. It is possiblefor noise on the input to pro-duce false level triggers andinaccurate readings. It is impor-tant to select a level that willprovide a reliable trigger source.For example, avoid the peaks of a sinewave since the signal ischanging slowly and noise caneasily cause false triggers.

6. For accurate readings, ensurethat your nearby environmentis electrically “quiet,” and useshielded test leads. Enablinglevel filtering, LFILTER ON,reduces sensitivity to this noise.

You configure the 34401A the sameway you configure the 34410A and 34411A. The 34401A uses ananalog circuit with a DC blockingcapacitor to convert the RMS voltage. The 34401A is specified tomeasure down to 3Hz. To makethe best possible measurements,select the low frequency filter, usemanual ranging, and verify thatany DC offset is stable. When youuse the slow filter a 7-second delay is inserted to ensure themultimeter is settled.

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8

Four types of transducers arecommonly used for making tem-perature measurements with adigital multimeter: resistancetemperature detectors (RTDs),thermistors, IC sensors and thermocouples. Each type hasadvantages and disadvantages.

Use thermistors for better sensitivity

Thermistors consist of semicon-ductor materials and provideexcellent sensitivity, but theirtemperature range is limited,commonly from -80°C to 150°C.Thermistors have highly non-linear temperature-resistancerelationships; therefore, theirconversion algorithms are complex. Agilent multimetersuse the standard Hart-Steinhartapproximation to provide accu-rate conversions, with a typicalresolution of .08°C.

Use RTDs for more accuracy

Resistance temperature detectors (RTDs) provide very accurate, highly linear relation-ships between resistance andtemperature, over a range of roughly -200 to 500°C.Modern multimeters such as the Agilent 34410A providemeasurement for the IEC751standard RTD, which has a sen-sitivity of .0385 ohm/ohm/°C.

IC temperature sensors produce a linear voltage per degree C

Many vendors provide probesthat produce a voltage propor-tional to temperature in degreesC or F. The probes typically usean IC temperature sensor such as the National SemiconductorLM135 series. A temperature IC can cover temperatures from -50°C to +150°C. You can easilycompute the temperature fromthe probe output shown on themultimeter display. For example,270 mV is 27°C.

Thermocouples offer extreme temperature measurements

Thermocouples can measure thebroadest range of temperature,from -210°C to 1100°C, and theirrugged construction makes themideal for harsh environments. Unlike other temperature sensors,thermocouples make a relativemeasurement and require a reference junction to make anabsolute measurement. For mostapplications it is not practical to add an external reference junction. We recommend usingthe Agilent 34970A data loggerwith a 34901A 20-channel multi-plexer with built-in referencejunction. The 34970A also hasbuilt-in temperature algorithmsfor common thermocouples.

Summary

For monitoring a single temper-ature, a thermistor and a multimeter like the 34410A make a simple low-cost solution.For more accurate temperaturereadings, use an RTD. Whenmonitoring many temperaturesor high temperatures, a dedicateddata logger is the best choice.

Selecting transducers

for making temperature

measurements with a

digital multimeter

RTD Thermistor IC sensor Thermocouple

Measurement Absolute Absolute Absolute Relativetype

Advantage • Most stable • High sensitivity • Most linear • Wide temperature • Most accurate • Low thermal • Highest output range• More linear than initiative (fast) • Inexpensive • Rugged

thermocouples • 2-wire measurement • Self-powered• Inexpensive• Wide variety of

physical forms

Disadvantage • Expensive • Nonlinear • Limited to 250°C • Nonlinear• High thermal • Limited temperature • Requires power • Low output voltageinitiative (slow) range supply • High thermal initiative

• Requires current • Fragile • High thermal (slow)source • Requires current initiative (slow) • Requires reference

• Small resistance source • Self heating • Connection, oxidationchanges • Self-heating • Limited configur- • Least sensitive

• 4-wire measurement • Should use 4-wire ations• Self-heating measurement for

high temperatures

Table 1: Comparison of common types of temperature transducers

5Hint

9

Multimeters often use a two-leveltriggering system; to make a reading, both sets of triggeringconditions have to be satisfied.Figure 6 illustrates the two-leveltriggering model used in the34401A multimeter. Typically thenumber of samples and numberof triggers is set to one when a trigger is received a single reading is taken. The number of samples can be increased to take N samples when a single trigger is received. If thenumber of samples is left equal to one and the trigger count is increased to N, then a triggerwould be required for each reading. In both cases, a triggerdelay is inserted between each reading.

Trigger delay by default is config-ured by the multimeter to allowthe measurement to settle, and itvaries depending on range and

function. The trigger delay can beset manually. It is important tonote that the delay is implementedin software and will have sometime variation. In addition,measurement time tends to vary, so it is difficult to use thisscheme to sample a signal on aregular interval. Figure 7 demon-strates a series of measurementstaken using a trigger delay.

A second trigger model is shownin Figure 8. This model is used inthe 34410A, 34411A and 3458A.It allows the trigger delay and the time between samples to be set independently. In addition, the sample loop (n readings) is designed to make readings quickly and withminimal variation in time. Mostof the sample loop is implementedin hardwarewith a minimum offirmware to insure consistent timing. The 34410A, 34411A and3458A can be configured to take sample readings as fast aspossible or using a timer.

To configure a burst of measure-ments, set the trigger delay toallow settling after the triggerand before the first reading. Usethe timer to set a precise intervalbetween readings. The 34410Aand 34411A have a front-paneldata logger feature that simplifiesconfiguring a burst measurement.

Making a group

of measurements

with a multimeterFigure 6:

A simple trigger scheme that uses a triggerdelay to space readings over time

TRIGGER INITIATE

WAIT FORTRIGGER

TRIGGER

TRIGGERCOUNT≠1

SAMPLECOUNT≠1

TRIGGER DELAY

MAKE READING

Figure 8:

Trigger model used in the 34410A and 34411A.Allows for precise timing between readings

INITIATE TRIGGER

WAIT FORTRIGGER

N READINGSCOMPLETE

NO

YES

TRIGGER

TRIGGER COUNT ≠ 1

SAMPLE COUNT ≠ 1

TRIGGER DELAY

START TIMER

MAKE READINGWAIT FORTIMER

Figure 7:

Measurements taken using trigger delay,where each measurement takes a differentamount of time to complete. This model is notideal for sampling a signal because the timebetween the start of each measurement varies.

MEASURE-MENT

TRIGGER DELAY

TIME

MEASUREMENTTRIGGER DELAYMEASUREMENT

TRIGGER DELAY

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6Hint

10

Multimeters are well suited forsampling low-frequency signalsusing the DC function. Typically,the bandwidth will be limited to8 kHz or less. Traditionally, ananalog peak detect circuit wasused to capture and hold thepeak voltage until an A/D circuitcould measure the voltage. Thistechnique provides high band-width and is still used to capturepeaks of very short duration. It also is used in multi-channelsystems where a single A/D isused in conjunction with a peak detector on each channel. A more common technique is to sample a signal very quicklyand store the largest and thesmallest value.

For many applications, the energy contained in noise spikesdisplayed on an oscilloscope display is of little consequence.Often, the noise is created byEMI and can mask the signal ofinterest —for example automobileengines generate a tremendousamount of EMI. Physical meas-urements—such as those madeby temperature or oil sensors—typically change fairly slowly.You can reject high-frequency

noise using a filter and a slowerA/D. It is not necessary to use a high-speed A/D to sample theoutput of a filter.

A multimeter is often a veryappropriate tool for determin-ing and measuring peaks. A multimeter provides signal conditioning (gain, attenuation,and low pass filtering) alongwith a reasonable sampling rate (1 KSa/s to 50 KSa/s). Most multimeters have a built-in math feature that you can use to determine the maximumand minimum value. To get thehighest reading rate, you mayneed to post-process the data, as the math function may slowthe reading rate. Other ways toincrease reading speed includeselecting a small aperture, turning off autozero, and turning off the display.

Characterizing a signal anddetermining the peaks is such acommon task that Agilent’s new34410A and 34411A multimetersinclude a peak detect feature.When you monitor a DC signal,you can use the second display to show the maximum peak, minimum peak and the peak-to-peak value. The peak detect feature is always sampling at 50 KSa/s, regardless of the multi-meter’s aperture setting, andmath is not required. Figure 9shows that the peak reading will normally be updated foreach reading.

Detecting Peaks

with a Multimeter

7Hint

11

DC MEASUREMENT 1 DC MEASUREMENT 2

PEAK 2

PEAK 1 DCVALUE 1

0 V

DCVALUE 2

Figure 9:

A peak measurement is made with each measurement.

DC MEASUREMENT 1 DC MEASUREMENT 2

DCVALUE 1

0 V

DCVALUE 2

PEAK 1

Figure 10:

A single peak measurement will bereturned for a set of readings.

DC MEASUREMENT 1

0 V

PEAK 1

DCVALUE 1

Figure 11:

A single peak will be returned for ameasurement, but the measurementcan be made over a long period.

The alternative to making a single read-ing is to set up a group of readings thatwill return a single peak measurementresult for the group of DC readings asshown in Figure 10.

A third alternative is to change themultimeter’s aperture and make onelong reading. The third method isillustrated in Figure 11. A single peakmeasurement will be returned for thelonger measurement.

The 34410A and 34411A peak detectwill sample the signal every 20 µs.The peak will be held until the nexttrigger. You can change the apertureto hold a peak value for a longer period of time. Each peak measure-ment will provide peak to peak, peak maximum and peak minimum.

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12

Easier probing

Often, you need two hands andboth eyes to probe a PC board;looking up at the multimeter display may cause the probes toslip. Some multimeters, like the34401A, 34410A and 34411A,offer a reading Hold feature thatlocks in a valid reading. Freezingthe reading allows you to con-centrate completely on probing.Using the Agilent 34133A precision electronic test leadscan make the job even easier.The test leads are small, light-weight and feature Agilent’spatented browser, which uses a crown point pogo pin. Thespring-loaded tip helps absorbthose small movements and thecrown point digs into solder.

High-voltage and high-current probing High-voltage probes enable youto measure high voltages safelywith a multimeter. The Agilent34136A high voltage probe isdesigned to be used with the34401A, 34410A, and 34411A inthe fixed input impedance mode(input resistance of 10 MΩ). Theprobe is a 1000:1 divider thatextends a voltmeter’s measure-ment capability to 40 kV DC.

If you want to measure DC and low-frequency AC current(to 30 A, and 15 A continuous)try the Agilent 34330A currentshunt, (above) a precision 0.001-ohm resistor housed in a plastic case surrounded byepoxy. Output is 1 mV per A of current passing through theshunt. The current to be meas-ured is connected to the shuntvia binding posts. Simply insetthe wire and tighten the bindingpost for easy connections.

Using accessories

to get the most

from your

multimeter

8Hint

13

Keep your probes and manual with the instrument

Ever wasted time hunting foryour probes or user guide? You’ll always know right wherethey are if you store them in aninstrument “backpack.” Agilentoffers two sizes of nylon pouchesto fit on top of our most popularmultimeters. The 34162A pouchis specially designed to fit onshorter instruments, such as the34410A and 34411A mutimeters.The 34161A pouch fits 34401Aand 34420A mulitmeters.

Making four-wire ohm measure-ments? Order additional probes.

If you are making four-wire ohm measurements, you need a second set of leads. 34138Aleads are identical to the onesthat ship with the 34410A and 34411A. They include somefine-tip probes and mini grab-bers. Agilent’s 34132A deluxetest leads kit includes two testleads, spring-loaded retractablehook leads, alligator clips, needlepoint and a reusable nylon case.

Create a neat wiring harness and minimize offsets errors

The Agilent 34171B DMM inputterminal connector block is a setof two connectors that providesa convenient and reliable methodto connect wires to all five inputterminals. Terminals are madeof low-thermal copper alloys tominimize thermally induced volt-ages caused by dissimilar metals.It is compatible with the 34401A,34410A, and 34411A. For mini-mum thermal offset voltages,use unplated copper wire of thesame gauge for all connections.

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14

Get even more accuracy and performance than you've come to expect

The Agilent 34410A and 34411A61/2 digit DMMs—the latest gener-ation of multimeters from Agilent—build on the phenomenal successof the industry-standard Agilent34401A. These new meters offerimproved accuracy, expandedmeasurement capability, dramat-ically improved measurementspeed and throughput, and mod-ern computer interfaces includingLAN and USB—so you can makefast, accurate measurements andtransfer them to your PC withease. The dual display offersdual measurement capabilities

and makes it easy for you to set up and configure the DMM.We’ve made improvements inevery facet of the 34401A tomake the best even better,whether you use it on the benchor in a system.

Dramatic speed improvements

Whether you need raw readingspeed or fast system throughput— or both—the 34410A sets a newbenchmark in performance. Usingnew A/D technology, the 34410Aachieves an impressive 10,000readings a second at 51/2 digits,and can stream readings to yourcomputer at this same speed.Triggering is fast and precise,with both trigger latency and

trigger jitter less than 1 µs, whilebus query response is less than500 µs. ACV measurements arefaster as well, thanks to a digitalmeasurement technique that further improves accuracy athigh and low frequencies. Foreven greater reading speeds,select the 34411A, which achieves50,000 readings/second at 41/2 digits.

The performance you need

The 34410A and 34411A offertemperature and capacitancecapabilities, in addition to thosemeasurements you have come toexpect, such as DCV, ACV, DCI,ACI, 2-wire and 4-wire resistance,frequency, period, continuity anddiode test. You also get offset-compensated ohms, allowing youto accurately measure resistancein the presence of voltages.Measurement ranges have beenexpanded as well; for example,DC and AC current ranges nowgo down to 100 µA, resulting in100 pA resolution. Real-timemath and statistics are included,and a peak detect capabilityallows you to capture peaks asshort as 20 µs.

Make unattended measurementswith the data logger function

A front-panel data logger func-tion allows you to set the meterup to make unattended, pacedmeasurements over a fixed timeor number of events, then pullup the results later for review or transfer to a computer foranalysis. Set the meter up to takemeasurements every 10 secondsfor an hour, go have lunch, andcheck the results upon yourreturn. The contextual front-panel sequences make setup and read back a breeze.

Introducing the next generation of industry-standard multimeters

34401A 34410A 34411A61/2 digit DMM high-performance enhanced performance

61/2 digit DMM 61/2 digit DMM

All of the 34410Afeatures, plus:

1,000 rds/s 10,000 rds/s 50,000 rds/s @ 41/2 digits continuous @ 51/2 digits @ 41/2 digits

512 rds memory 50,000 rds non-volatile memory 1 M reading memory

DC accuracy 0.0035% DC accuracy 0.0030% Analog level triggering

GPIB and RS-232 standard LAN, USB and GPIB all standard Pre- and post-triggering

Capacitance and temperature

Data logger capability

Dual display

Agilent 34410A and 34411A digital multimeters offer improved speed, more performance, additional memory and more PC connectivity options than the 34401A.

34401A digital multimeter, 61/2 digitThousand of engineers worldwidecount on the Agilent 34401A forfast, dependable results, knowingthe last measurement of the daywill be as accurate as the first:24-hour accuracy is 0.0015% forDC volts and 0.06% for AC volts.One or two button presses giveyou a wide array of functions,from DC volts to frequency to dBand dBm. Advanced tests includelimit checks, min/max/avg read-outs and dc voltage ratios.

3458A digital multimeters, 81/2 digitWhen your tests demand speedand accuracy without compromise,the Agilent 3458A offers rates up to 100,000 readings, 110auto-ranges and more than 340setup changes per second. If precision is the priority, select81/2 digit resolution with 0.1 ppmtransfer accuracy. Twenty fourhour accuracy is 0.6 ppm formid-band ac volts. You can alsouse the extensive set of math and filtering functions to improveyour measurement accuracy.

34420A nanovoltmeter, 7 1/2 digitThe Agilent 34420A nanovolt/micro-ohm meter is optimizedfor precision low level measure-ments, with 71/2 digit resolutionand 1.3 nVrms/8 nVpk-pk noiseperformance. Two input channelslet you make voltage measurementsindependently or mathematicallycombine them for difference and ratio measurements. DirectSPRT, RTD, thermistor and thermocouple measurements let you track a wide range of temperature sensors.

L4411A digital multimeter, 6 1/2 digitNow available in a 1U half racksize, the L4411A 61/2 digit enhancedperformance digital multimeter.This instrument includes all ofthe features and capabilities ofthe 34411A in a compact sizeoptimized for use in manufacturingenvironments where space is ata premium.

Function Range Frequency, 1-year Tcal ± 5°Ctest current orburden voltage

DC voltage 100.0000 mV 0.0050 + 0.00351.000000 V 0.0035 + 0.000710.00000 V 0.0030 + 0.000510.00000 V 0.0030 + 0.0005100.0000 V 0.0040 + 0.00061000.000 V 0.0040 + 0.0006

True RMS AC voltage 3 Hz – 5 Hz 0.50 + 0.035 Hz – 10 Hz 0.10 + 0.0310 Hz – 20 kHz 0.06 + 0.0320 kHz – 50 kHz 0.10 + 0.0550 kHz – 100 kHz 0.40 + 0.08100 kHz – 300 kHz 1.20 + 0.5

Resistance 100.0000 Ω 1 mA 0.010 + 0.0041.000000 kΩ 1 mA 0.010 + 0.00110.00000 kΩ 100 µA 0.010 + 0.001100.0000 kΩ 10 µA 0.010 + 0.0011.000000 MΩ 5 µA 0.012 + 0.00110.00000 MΩ 500 nA 0.040 + 0.001100.0000 MΩ 500 nA – 10 M 0.800 + 0.0011.000000 GΩ 500 nA – 10 M 8.000 + 0.001

DC current 100 µA to 3 A ranges

AC current 100 µA to 3 A ranges

Frequency (period) 3 Hz (0.333 s) to 300 kHz (3.33 s)

Capacitance 1 nF to 10 µF Range

Temperature RTD: -220 to 600°CThermistor: -80 to 150°C

Continuity 1000 Ω range, threshold 10 Ω fixed

Diode test 1 V range, 1 mA test current

Math functions statistics Null per range, min/max/avg, dBm, dB, limit test

Data logger Nonvolatile memory : 50,000 readingsVolatile memory : 34410A, 50,000 readingsVolatile memory : 34411A, 1,000,000 readingsSample timer, 0 to 3600 s, <100 ns jitter

Interfaces LAN, USB, and GPIB (designed to be LXI class-C compliant)

Maximum input DC /AC voltage : 1000 Vdc / 750 Vrms (1100 Vpk)DC and AC current : 3 A, from <250 V fused

Shock and vibration meets MIL-T-28800E, Type III, Class 5 (sine only)

Power 100/120/220/240 V, 45-66 Hz, 360-440 Hz25 VA peak (16 W average)

Net weight 3.72 kg (8.2 lbs)

Warranty 1 year

100.0000 mVto 750.000

15

Specifications: 34410A / 34411A digital multimeters, 61/2 digits

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www.lxistandard.orgLXI is the LAN-based successor toGPIB, providing faster, more efficient connectivity. Agilent is a foundingmember of the LXI consortium.

Remove all doubt

Our repair and calibration services will get your equipment back to you,performing like new, when prom-ised. You will get full value out ofyour Agilent equipment through-out its lifetime. Your equipment will be serviced by Agilent-trainedtechnicians using the latest factorycalibration procedures, automatedrepair diagnostics and genuine parts.You will always have the utmost confidence in your measurements.

Agilent offers a wide range of ad-ditional expert test and measure-ment services for your equipment,including initial start-up assistanceonsite education and training, as wellas design, system integration, andproject management.

For more information on repair andcalibration services, go to:

www.agilent.com/find/removealldoubt

www.agilent.com

For more information on Agilent Technologies’

products, applications or services, please

contact your local Agilent office. The complete

list is available at:

www.agilent.com/find/contactus

Americas

Canada (877) 894-4414Latin America 305 269 7500United States (800) 829-4444

Asia Pacific

Australia 1 800 629 485China 800 810 0189Hong Kong 800 938 693India 1 800 112 929Japan 81 426 56 7832Korea 080 769 0800Malaysia 1 800 888 848Singapore 1 800 375 8100Taiwan 0800 047 866Thailand 1 800 226 008

Europe

Austria 0820 87 44 11Belgium 32 (0) 2 404 93 40Denmark 45 70 13 15 15Finland 358 (0) 10 855 2100France 0825 010 700Germany 01805 24 6333*

*0.14 /minuteIreland 1890 924 204Italy 39 02 92 60 8484Netherlands 31 (0) 20 547 2111Spain 34 (91) 631 3300Sweden 0200-88 22 55Switzerland (French) 41 (21) 8113811(Opt 2)Switzerland (German) 0800 80 53 53 (Opt 1)United Kingdom 44 (0) 118 9276201Other European Countries:www.agilent.com/find/contactusRevised: May 7, 2007

Product specifications and descriptions in this document subject to change without notice.

© Agilent Technologies, Inc. 2007Printed in USA, August 23, 20075989-4279EN