RCL meters of type NJ100S / NJ200S / NJ300S

[GrayCat]

Hello!

Being in search for an RCL/impedance meter at around $100, I came across some NJ100S / NJ200S / NJ300S models. They have very good formal parameters, rich set of Variables to measure, but absolutely nothing is known about them! All I have found is some seller announsements, with the same pictures. And, User-Manual for NJ300S.



NJ100S Specifications:

Code: [Select]

- Product model: NJ100S (fixed frequency)
- Power frequency: 50Hz. Frequency points: 15. Frequency point value: 50, 100, 600, 1000, 6000, 10000, 20000, 30000, 40000, 50000, 60000, 75000, 80000, 93750, 100000.
- Power frequency: 60Hz. Frequency points: 13. Frequency point value: 60, 120, 600, 1200, 6000, 12000, 24000, 30000, 38400, 48000, 60000, 75000, 96000.
- Measuring ranges:
* Resistance: 0.2mΩ~500MΩ
* Capacitance: 5fF~150mF
* Inductance: 0.5nH~100kH
These seem to be very good values, but no any confirmation for them.

Does anybody know anything about them?

[GrayCat]

 

 NJ300S_Hand.jpg (101.35 kB - downloaded 138 times.)

[coromonadalix]

uh  aboslutely nothing    never saw them   ill try to find price for them,  where did you see them ?

Aliexpress ? Banggood ?

[GrayCat]

uh  aboslutely nothing    never saw them   ill try to find price for them,  where did you see them ?

Aliexpress ? Banggood ?

On EBay they are under the denoted names.

On Aliexpress, they are marked as "50Hz~100KHz-24 Frequency Points 2.4 Inch TFT Screen Handheld Tool LCR Meter Digital Bridge Impedance Tester", several sellers have them.

Any ideas?

[coromonadalix]

https://www.banggood.com/50-300KHz-Handheld-Impedance-Tester-Bridge-LCR-Digital-Resistance-Measurement-Capacitance-Adjustable-Inductance-p-1738414.html?p=PA19205493643201607I&custlinkid=1304842&ID=6296786&cur_warehouse=CN


https://www.aliexpress.com/item/1005001501380888.html



well got me tempted  for the black friday ?? 

[GrayCat]

well got me tempted  for the black friday ??

No. I just want to know, is that NJ100S superior to Hantek 1833C. While there are plenty of info on Hantek, nobody can tell anything on the NJ.

[coromonadalix]

Well someone has to buy one and do a teardown and firmware dump if its possible   .....

Until then  there's only speculations

[GrayCat]

Short video on testing a 80mm wire of 0.51mm diameter with NJ100S (in Russian):
 
https://youtu.be/POXDhURpUjY
 
Measure of "precise" 1 nF and  10 nF capacitors:

[GrayCat]

Measuring a 2 kOhm ±1% resistor:

https://youtu.be/dpYJAKPU5j4 (in Russian)

[coromonadalix]

can you open it to see the inside ?  thks

[GrayCat]

MCU: STM32F103RCT6 .
Charger TP4056 . Flash 25Q32JVS1Q .
OpAmps: U1 (voltage input), U9, U46, U47, U48 ==MCP6022. "Current Driver" U37==AD8532A. One more U7=AD8534A.
Switches something like 74LVC1G3157DCKR (markings "C5K" and "C5J").

[GrayCat]

All OpAmps were covered by some matte "epoxy".

[GrayCat]

The device was shipped without any probes. So, I had to make them myself.

The LCD is "YT240L030" on a ILI9341 controller, with 18-pin interface. So, you can buy a 3.2"-one, and feel more comfortable :-)

[GrayCat]

Measiring of a 1 Ohm ±1% resistor.

Measiring of a 90.9 kOhm ±0.5% resistor.

[coromonadalix]

Thank you very much for the teardown   

[MegaVolt]

There is more information about this device here:
https://ampnuts.com/lcr-nj100s/
https://ampnuts.com/start/

[Russ3000]

I bought the device on aliexpress. I will compare with 1832.

[ZhuraYuk]

I just wonder how it shows 6 digits having only 12 bit ADC built in STM32