Amprobe 34XR-A | Test Meter Pro

This is an auto-ranging, True RMS digital multimeter fit for bench and field work, including electrics and electronics. Especially useful for motor drive diagnostics, the Amprobe 34XR-A also comes with a temperature input and backlit display. Despite the age of this series and the odd issue, these meters often outperform pricier options.

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Ships With

Rubber boot and 9V battery
Test leads / alligator clips
Thermocouple (K-type)
Magnetic hanging strap
Spare milliamp fuse
Instructions (amprobe 34xr-a manual)

Key Features

True RMS for AC accuracy
DC voltage to 1000V, AC to 750V
Amperage (to 10A), milliamps and micro-amps ranges
Measures temperature in °F and °C
Measures frequency to 40MHz
Resistance to 40MΩ
Auto ranging, plus range lock
Min/Max mode for recording lows and highs
Backlit display
Wrong lead input warning
Weight: 14oz (400g) – with battery

In-depth Review of the Amprobe 33XR-A

The Amprobe 34XR-A is part of the older XR-A Series from Amprobe. Though somewhat surpassed nowadays by more modern meters, it is nonetheless well-built, reliable and fairly accurate. It has the measurement ranges that most amateurs and pros would need, including voltage, current, resistance and continuity, capacitance, frequency and duty cycle. You also get temperature and diode check.

There are separate range positions for the amperage scales, AC and DC. It measures micro-amps, so can be used for some HVAC work and electronics tasks. You also have milliamps and amperage (to 10A) on both AC and DC. The resistance range is okay, going up to 40MΩ, though capacitance could do with being fatter, and frequency extending a bit lower.

Sadly, although the 34XR-A has a useful Min/Max recording feature, it does not have a relative mode, of which the 33XR-A does. Extras include a thermocouple probe (for measuring temperature), alligator clips that fit on the ends of the test leads, plus a magnetic hanging strap.

True RMS Accuracy
Multimeters not True RMS responding are known as ‘Average’ RMS meters. While these can measure standard AC and DC signals accurately, when it comes to distorted waveforms (such as those from an inverter output), the estimated RMS value will typically be inaccurate. Along with motor control, True RMS would be beneficial for reading power supplies, florescent lighting, controllers, pulsed signals etc.

Ranging Options
Aside from capacitance and amperage, the Amprobe 34XRA is an auto-ranger, too, meaning you set it to the range and it will pick up the decimalized value automatically. This doesn’t read as fast as standard manual ranging, however, but you also have the option to manual range with the 34XR-A. The range lock button achieves this.

SPECS

Range		accuracy	resolution
AC voltage (45-500Hz)	400mV / 750V	±(1.2%+8)	100µV
DC voltage	400 mV / 1000V	±(0.5%+1)	100µV @ 400mV
AC current (45Hz-1kHz)	400µA / 10A	±(1.5%+8) @ 400µA-300mA	0.1µA
DC current	400µA / 10A	±(1.0%+1) @ 400µA-300mA	0.1µA
Resistance	400Ω / 40MΩ	±(1.0%+4) @ 400Ω-4MΩ	100mΩ
Capacitance	4µF / 4000µF	±(5.0%+5) @ 40-400µF	1nF
Frequency	4kHz / 40MHz	±(0.1%+3)	1Hz
Duty cycle	0 to 90%	±(2.0%+5)	0.1%
Temperature °F	-4°F to 1832°F	±(1.0%+6°F) @50-400°F	1°F
Temperature °C	-20°C to 1000°C	±(1.0%+3°C) @ 10-200°C	1°C
Diode test	3V	±(1.5%+3)	1mV

Design / Build

It is quite well engineered, with a strong case that is enclosed in a rubber holster. It’ll take a certain amount of abuse, though is not watertight. The dial is also quite accurate, and there is a separate lid on the rear for battery/milliamp fuse access. It might not look as slick as newer meters, but the Amprobe 34XR-A is quite well designed inside and out.

Interface

The 4000-count display (3-3/4 digit) is not the best, having fairly small digits compared with most meters nowadays, and which are prone to washing out. It does, however, come with a bar graph and has a nice, blue backlight. This turns off automatically after a minute or so.

Beneath the display are four function buttons, including Min/Max, backlight, Range, and display hold. The input jacks sit at the bottom and are clearly labeled, being quite obvious which one does which, with the common (black lead) in the middle.

Protection

The two amperage inputs (amps / milliamps, micro-amps) are protected by 10A and 315mA HRC fuses respectively. You can replace the milliamp fuse from the battery lid via two screws, with the main fuse accessed via further removal of the four case screws.

34XR-A Replacement Fuses
FP300: 315mA
FP100: 10A

The circuit board has a modicum of input protection for CAT-II (1000V) and CAT-III (600V) installations – accommodating potential surges at those given energies. A daughter board accommodates the input jack circuitry.

Lead warning: The beeper will sound should you inadvertently plug into an amperage socket and select the wrong function.

Function and Performance

The Amprobe 34XRA will probably need to change batteries more often than some of the lower models due to the addition of a backlight. You could expect around 100-200 hours work out of it. An auto sleep mode helps to extend this, cutting in after 30 minutes when not active to conserve the battery.

The continuity test is reportedly a bit slow and the beeper a tad irritating, but one should try to avoid comparing this side of it to a Fluke, which are renowned for their super-fast beepers.

Pros and Cons

PROS

True RMS
Measures temperature and capacitance
All amperage ranges
Auto and manual ranging
Backlit screen
Includes a Magne-Grip strap
Okay price considering brand and features

CONS

Slow continuity
Disappointing display despite backlight
No REL (relative) mode
Capacitance range narrow

Conclusion

It’s not without its flaws, such as a tired display and sluggish continuity checker, but the Amprobe 34XR-A is a pretty good meter overall. The main draw over the lower rated 33 and 30 models of the XR-A series is that the 34XR-A is True RMS. It also has a backlit screen, though this series does struggle with its displays compared to the newer series’ in general.