I have two of them. There are many issues, but for the price I am happy.
All of the ranges I have tested have been well within their specified accuracy, but I have not evaluated the frequency response or accuracy of the rms converter yet. I will update this when I do. The stated frequency range of 40-200 Hz is only usable for AC power waveforms, not audio. When I checked the AC response of my units they worked up to almost 1000 Hz.
The PEAK( min/max) and REL(delta) buttons do not work on any range.
The APO (automatic power off) function is on by default. To turn off the APO function hold down the HOLD button while turning the meter on, not the SELECT button as the Chinglish instructions state.
The meter does appear to have a couple of input protection diodes and a tiny varistor, but the protection circuitry seems to be inadequate for use on power lines. However for most other uses it seems fine. I have used it opn tube gear with voltages up to 800V without issue.
The bar graph although marked with 100 small segments is only 20 sections bar graph, each section being 5 marked segments. The numbers on the bar graph 0, 5, 10, & 20 correspond to the bar graph sections.
The sound response of the continuity check function seems instantaneous, even though the meter indication is much slower.
The temperature on mine reads high; 4ºC at 0ºC and 102ºC at 100ºC. I suspect the error is in the metals of the banana plugs and jacks since small computational changes can change contact potential.
There is no specification for input impedance, so I will measured it:
DC Range Input Z
2V 11MEG
20V 10MEG
200V 10MEG
1000V 10MEG
AC Range Input Z
0.2V 11MEG
2V 10MEG
20V 10MEG
200V 10MEG
diode mode:
open circuit V: 3.23V
test current: 1.6mA
maximum displayed value 2.2V
continuity mode:
open circuit V: 1.0V
test current: 380uA
response seems instantaneous
The markings in the battery department are not obvious. I marked mine with a marker pen
The NCV (non-contact voltage) function seems very sensitive. The sensor is in the left side of the meter at about the center of the display. There is no indication where it is.
I paid $21 for mine and I'm satisfied with the purchase. It is now down to $16 on Amazon.