More out of curiosity than anything else I grabbed one of these KKM828 graphical meters.
I have found this exact same device branded 4 different ways:
KK Moon KKM828
BangGood MT8208
Unbranded ET828
Liumy LM2020
The price is all over the place. If you shop you should be able to get one in the US for $50 to $60 delivered.
For comparison, from the same designers/factory there is
MT8206 20 KHz BW, 200 ksample/sec
240x160 monochrom LCD
2000 count not TRMS, no Temp DMM
See HKJ's review at
https://lygte-info.dk/review/DMMMustool%20MT8206%20UK.html MT8208 1 MHz BW, 2.5 Msample/sec
320x240 color display
4000 count not TRMS, no Temp DMM
MDS8207 40 MHz BW, 200 Msample/sec
240x160 Monochrome LCD
6000 count TRMS with Temp DMM
See HKJ's reveiw at
https://lygte-info.dk/review/DMMMustool%20MDS8207%20UK.htmlThere are many hand held "real" oscilloscopes in the $100 and up category that would put the KKM828 to shame for oscilloscope functionality. Most importantly, any "real" oscilloscope should have at least two channels to be able to do debugging with. Any single channel scope will be inherently a limited use case item. Looking at any signal with a meter's unshielded leads compared to an oscilloscope probe is asking for trouble above 10 MHz and maybe even between 1 and 10 MHz.
What really impressed me about the 8208:
- The oscilloscope function is actually reasonable. Yes limited but for what it is reasonable.
- The oscilloscope function works for the current measurement mode!!
The higher BW 8207 has a dedicated input terminal for the oscilloscope function and presumably only works for voltage mode. "Real" hand held oscilloscopes also would only measure voltage.
In conclusion, I was less impressed with the DMM part than I expected and more impressed by the scope part than expected. As an additional tool I think this "graphical meter" can justify itself via quick portability to check for existence of signals or for signal tracing. As a starter oscilloscope or "real" oscilloscope replacement it would be a poor choice.
Pros: Oscilloscope function works on the current ranges!!! 30 mA/div is very clean/noise free.
Pretty good color display (twice resolution of other ones)
Controls are reasonable
Trigger works surprisingly well
Cons: Fairly poor battery life for a hand held DMM...probably 65 Hour
Not TRMS
I couldn't figure out how to make scope ac coupling. Always dc coupled
mA current range is only 250 kHz BW while voltage is over 750 kHz
10A current range is probably lower BW also but didn't readily have 1+ ampere test signal handy
Fastest sweep is only 2.5 uSec/div. Quoted 1 MHz BW implies 0.35 uSec step rise time
Quirks: Must enter scope from V/I ac and not dc.
- Scope is dc coupled even started from ac mode
If you enter from V/I dc step response is way under calibrated....unusably so
You can enter oscilloscope mode from mV range for 30 mv/div. But, step response is waaaay under calibrated.
- There is no mV ac mode to start in. Only dc.
F4 held at turn on can turn beeps off...but setting is not remembered
To measure higher capacitances must switch leads to two middle meter terminals
FYI: Works fairly well with 3 rechargeable NiMH batteries. Fresh battery shows half full symbol.
IMHO: For this category best would be use meter leads and have 5-10 MHz BW, 25 Msample/sec
- Higher BW makes no sense with meter leads.
- Leave higher BW applications to "real" 2 or more channel scopes with scope probes.
Like the 8208 also work with current mode.
- clamp meter would be awesome...but perhaps struggle with screen size
At least twice battery life
ac/dc coupling switchable