I own a U1273A and a U1282A and had owned a U1233A. I haven't used the U1233A enough to have a strong opinion other than its size and packed features are a very nice feature. I tend to prefer the U1273A but the U1282A has its uses.
Leeching off bitseeker's excellent response, I have the following addenduns:
(I may be forgetting a few things)
U1273A:
- OLED display. The most controversial factor of this meter. Unbeatable indoors legibility and, if used in dark conditions, you will never be caught with a dark display (due to backlight timeout) while trying to evaluate the best places to put the probes. Its durability is unknown and various reports around this forum are concentrated on the previous model U1253 (only one or two concerned this model). Mine still works after 4~5 years of manufacturing (about 1-1/2 years of moderate use of about 1 hour per day). Threads
here,
here,
here and
here (there may be others).
- Decent speed autorange.
- Frequency measurements do not require the signal to have zero crossing - good for signals with DC offset. (common to U127x/U128x)
- Various hold mechanisms (common to U127x/U128x), including a trigger (like an oscilloscope) and Auto hold.
- Built-in data logging with different trigger modes - the one I use the most is the event trigger, which allows to log only when a stable input is detected. (common to U127x/U128x)
- Low impedance ACV/DCV mode for eliminating ghost voltages (LoZ). Since in the bench I use several boards and power supplies and host PCs interconnected, this mode is quite useful to detect wide ground variations in unknown conditions. Lowest voltage difference is 3V
AC -
here- Can compensate for DC offset voltages when measuring resistance (smart ohms). I personally have seen myself using this mode more than I initially believed during my repairs around the house on HVAC, heater and other permanent installations.
- Good capacitance meter with excellent range: up to 33mF. Slow on auto-range, especially on higher ranges (somewhat expected).
- 3V Diode checker that tests in both directions so you don't have to swap the leads.
- Beep can only be fully disabled or fully enabled. No sensible settings to disable the turn on beep.
- Continuity tester has a very interesting melody setting. A gimmick.
- Uses AAA batteries (common to U127x/U128x). Not a big fan due to the fear of leakage, but this meter sees quite a bit of action and the batteries usually are replaced every 6~8 months with my use.
- Very well built and a bit tall for my taste, but it has good rotary switch and terminal jacks. The various buttons with the number of aggregated functions not always make much sense - I sometimes see myself pressing a number of buttons until I get what I want or just need to go back to the previous display.
- I love its leads (Dave dislikes them due to length) as they have banana jacks on both sides. Easy to plug accessories.
- Earlier versions, like mine, were sensitive to high-frequency RF on the input jacks that could alter the displayed value.
U1282A:
- LCD Display. Excellent size and quite clear.
- Its biggest drawback to me is the slow autorange.
- Frequency measurements do not require the signal to have zero crossing - good for signals with DC offset. (common to U127x/U128x)
- Various hold mechanisms (common to U127x/U128x), including a trigger (like an oscilloscope) and Auto hold. However, on this meter the switch between the different auto-hold modes only via a setup menu - the U127x cycles as you press the button. To me this detracts from the functionality.
- Built-in data logging with different trigger modes - the one I use the most is the event trigger, which allows to log only when a stable input is detected. (common to U127x/U128x). Other modes are manual and timed - quite useful as well.
- It has NCV with configurable sensitivity settings. Despite this, I find this NCV still too sensitive for reasonable use. I prefer to use my Fluke LVD2 that is a spot tester.
- Good capacitance meter with excellent range: up to 100mF. Slow on auto-range, especially on higher ranges (somewhat expected).
- It has square wave output with configurable duty cycle and frequency. Since the frequency is only switchable on the setup menu, it is somewhat cumbersome to use for my taste.
- It has an input for remote control to perform manual hold of measurements. Perhaps it has its uses for others, but I haven't seen the need to purchase its accessory.
- 3V Diode checker. Lacks the auto-diode feature of the U127x that I like.
- Beep can be disabled more sensibly than U127x - either disable the turn on beep (leaving continuity beep still on) or disable everything.
- Uses AAA batteries (common to U127x/U128x). Not a big fan due to the fear of leakage, especially because one of its big advertisements is the very long battery endurance. Better check them constantly.
- Very well built and large meter that can easily act as a weapon. It has rubbery feel rotary switch (if that is an issue or not it is a highly personal matter). The various buttons with the number of aggregated functions not always make much sense - I sometimes see myself pressing a number of buttons until I get what I want or just need to go back to the previous display. IP67 rated, but mine only sees action on the lab.
- Decent leads but do not allow plugging accessories.
- Came with USB accessory for firmware updating and data logging. A big plus to me.
- Did not come with the temperature probe. A fail in my opinion.
- Not plagued by high-frequency RF problem of the early U127x modes.
Interesting clips about autorange comparison and the melody setting (shameless plug)
Melody continuity:
Autorange comparison:
I currently have the models shown below and will list some of the interesting or different features. Check the docs for details, of course. I really like the fast sampling/update rates of their meters. All three will work with the same USB or Bluetooth remote logging interfaces. They all have excellent, evenly lit backlights.
U1272A: LCD display. Dual 33,000 counts. Auto hold. Built-in data logging. Has low impedance ACV/DCV mode for eliminating ghost voltages. Can compensate for DC offset voltages when measuring resistance. Also has a diode checker that tests in both directions so you don't have to swap the leads. Uses AAA batteries (300 hours). Almost identical in size to the U1252B, but its concave sides make it feel slimmer in the hand (better for those with smaller hands). Earlier versions, like mine, were sensitive to high-frequency RF on the input jacks that could alter the displayed value.
U1282A: This is like an upgraded/enhanced U1252B. LCD Display. Dual 66,000 counts. IP67 rated. Auto hold. Low-frequency square wave generator (0.5 – 4800 Hz) with adjustable duty cycle. Built-in data logging. Measures % of 4 – 20 mA or 0 – 20 mA for industrial current loop transmitter output. Non-contact AC voltage detection. Remote hold (optional probe required). Includes the USB logging interface cable. Uses AA batteries (800 hours). Large case, longer than the U1252B and U1272A plus additional protective protrusions (i.e., it's a big DMM and heavier than the other two).
For me, the U1252B is a great all-around DMM. For electronics, it retains full resolution to 5V whereas the U1272A drops a decimal place above approximately 3V. The signal generator is also handy for checking out used equipment at auction houses (e.g., frequency counters, oscilloscopes, and the like; however, it'd be nice if it went up to a few MHz).
The U1272A's LoZ mode is nice for electrical work. The diode tester is convenient for electronics. I haven't taken advantage of the auto DC offset compensation in resistance mode, but it's a neat idea.
The U1282A's NCV function is a nice addition and the rest being like the U1252B would make this my go-to meter, but its size and weight make it less handy to take around. So, it lives most of its life as a bench DMM.