$20 LCR ESR Transistor checker project

[AlcidePiR2]

I have

measure 3 time a  film cap 1uF 1%  and adjust again, but this did not changed anything.  ( Mes A )

Then

- suppress the opto coupler option to give more room to the code ( 97% instead of 99.9 %)
- changed the  Low Fuse to 0xF7 instead of 0xFF  ( crystal)

reflash the chip,  measure 3 times the  film cap

Test
Adjustment

Then things improved and I get something that seems to be in par with what is expected from the 10 bit resolution of the AD converter of the Atmega328 ( 0.1%)  ( Mes B and B bis)


R   prec         Mes A      Mes B   Mes B bis
            
681   0.10%   680.2     680.1   679.3
475k   0.10%   474.4     474.4   474.2
100   0.01%   101.8     99.7     99.6
10k    0.01%   9801           9992    9993
1M     0.05%   998.6k     998.7   998.2


I dont know if anything better can be expected without adding an external ADC.

[indman]

AlcidePiR2
I suggest you make the same measurements on k-firmware 1.13k and compare the results.

[AlcidePiR2]

AlcidePiR2
I suggest you make the same measurements on k-firmware 1.13k and compare the results.

This is done with the I.13k

with the following changes in the autoconf.h because the resistors I had in 0.1% accuracy were not the 680/470k standards.


/* check the R_L_VAL and R_H_VAL setting */
#ifndef R_L_VAL
  #define R_L_VAL 6810         // standard value 680 Ohm, multiplied by 10 for 0.1 Ohm resolution
#endif
#ifndef R_H_VAL
  #define R_H_VAL 47500      // standard value 470000 Ohm, multiplied by 10, divided by 100
#endif


The results are comparable. Maybe slightly better

679.6
474.5
99.3
10.01-2 k (variations in a sequence of measures)
999.4-8 k (variations in a sequence of measures)

[de_light]

My saga with the esr02pro has taken a temporary pause as my friend needed his multimeter back and I am awaiting shipment of my new multimeter (with long delays from covid19).

The BSIDE people have kindly sent me out a free gift of the ESR02 (non pro) version, photo below. Does this look familiar to anyone in terms of a clone?

[madires]

Looks like a MG328 with a slightly modified probe area (connectors moved around).

[indman]

The BSIDE people have kindly sent me out a free gift of the ESR02 (non pro) version, photo below. Does this look familiar to anyone in terms of a clone?

I think that this clone is almost no different from MG328(BigDisplay) on my resource 
https://yadi.sk/d/yW8xa5NJgUo5z/MG328(BigDisplay)

[indman]

I updated the comparative table on clones and added information on 5V to the regulator and to referensny source 2.5V. I did not give exact marking of details as the Chinese vendors can use different marking and the name.

I updated the comparative table on clones and added information display size in inches,supply controller for LCR-T1/T7, update firmware version posible 

P.S Edit - Fixed some display size errors in inches

[Stan21]

Hello
I purchase the device from Kuman via Amazon https://www.amazon.com/gp/product/B071Y5CHPK
I ran self-adjustment
I noticed that device gives wrong values for hFE; so for MPS222A transistor it shows hFE 425 while 2 other testers (Synometer VC9808 and another one, Mastech) show consistently  250 which is more reasonable.
Can anything be done to fix that or I am just being unlucky with bad device?

[madires]

The hFE can differ based on test currents and voltages. Also be aware that the firmware of the transistortester measures hFE in a common emitter configuration and also in a common collector configuration. The higher value of both measurements is displayed. I can't say anything about the DMMs. But you can set up a simple circuit to measure the hFE yourself to verify the value.

[PedroDaGr8]

I updated the comparative table on clones and added information on 5V to the regulator and to referensny source 2.5V. I did not give exact marking of details as the Chinese vendors can use different marking and the name.

I updated the comparative table on clones and added information display size in inches,supply controller for LCR-T1/T7, update firmware version posible 

For your comparison, it would be good to indicate what is different between the AY-AT and the GM328A. This would help people in identifying their version. If there are no definitive differences, then it might be worthwhile to combine the two entries.

[indman]

GM328A(B) is a clone model that fully repeats the AY-AT model, but is assembled on SMD components(excluding processor in version A) and has a black board color. I do not know in which version GM328A is currently being produced, but according to the reviews of many owners of such models, they have an error in tracing the frequency meter circuit.

[Stan21]

The hFE can differ based on test currents and voltages. Also be aware that the firmware of the transistortester measures hFE in a common emitter configuration and also in a common collector configuration. The higher value of both measurements is displayed. I can't say anything about the DMMs. But you can set up a simple circuit to measure the hFE yourself to verify the value.

This only proves advantage of regular OEM LCR-meter. I have 2 and both show the same correct value of hFE.
One cannot expect any reliability from $7  toy made by amateurs enthusiasts.

[madires]

Have you verified by a manual hFE measurement that your DMMs show a reasonable value? Both DMMs might use the same measuring method, hence the matching values. BTW, a DMM is not an LCR meter.

[Stan21]

Have you verified by a manual hFE measurement that your DMMs show a reasonable value? Both DMMs might use the same measuring method, hence the matching values. BTW, a DMM is not an LCR meter.

I am not familiar with your slang and have no idea what 'DMM' is. I have an LCR-meter VC-9808, multimeter Mastech MAS345 and simple anlogue multimeter 5828. All 3 have hFE measurement, and all 3 show same hFE for MPS2222A in the range of 240-250, while this self-made gadget shows 425. I have no reason not to trust OEM meters.

[indman]

Stan21,
1. DMM is the common designation for Digital Multi Meter! It's a shame if you did not know these simple things before this time.
2. VC-9808, Mastech MAS345 - this is DMM! They are not specialized LCR meters, but simply have additional bonus options for measuring inductance, capacitance and transistor parameters.
3. You bought the LCR-T4 clone model, which has a very old Chinese mod firmware, in which so many important tests and calibration settings have been removed. Update the firmware on your clone, calibrate it as it should and then compare the readings hFE.

[madires]

No wonder that I haven't found any datasheet. It's an MPS2222A, and not an MPS222A as noted in your first post. The maximum hFE of the MPS2222A is 300. Yep, 425 is way off. And with indman's hint about the stripped-down and modified firmware I'd recommend to update your tester to one of the two genuine OSHW firmwares. After that you may blame us.

[Stan21]

Stan21,
1. DMM is the common designation for Digital Multi Meter! It's a shame if you did not know these simple things before this time.
2. VC-9808, Mastech MAS345 - this is DMM! They are not specialized LCR meters, but simply have additional bonus options for measuring inductance, capacitance and transistor parameters.
3. You bought the LCR-T4 clone model, which has a very old Chinese mod firmware, in which so many important tests and calibration settings have been removed. Update the firmware on your clone, calibrate it as it should and then compare the readings hFE.

Don't do nitpicking, 9808 has iductance, capacitance and resistance, hense LCR and this is how it is positioned on a market; MAS345 does not have inductance so it is not LCR, 5828 is not digital so it is not 'DMM'. And _ANY_ of this has nothing to do with subject. It is a shame for you to wase the thread with off-topics.
You don't know this is 'old Chinese firmware' and your guess is just a wishfull thinking. And that exactly model from the same seller had positive review 5 years ago. https://hackaday.com/2015/04/24/review-transistor-tester, and also a very good rating on Amazon.
When I by a 'tester', I want to open the box, connect a battery and start testing instead of wasting time on browsing 250-pages for the search of 'genuine warranted Snark' that may or may not make that crappy gadget functional. Well, obviously that does not work for a cheap gizmo.
So you should be ashamed of your arrogant and biased attitude. Have a potato.

[Stan21]

No wonder that I haven't found any datasheet. It's an MPS2222A, and not an MPS222A as noted in your first post. The maximum hFE of the MPS2222A is 300. Yep, 425 is way off. And with indman's hint about the stripped-down and modified firmware I'd recommend to update your tester to one of the two genuine OSHW firmwares. After that you may blame us.

Where is a link on 'two genuine OSHW firmwares' update instruction?

[indman]

Stan21,
I’ve seen a lot of trolls like you in my time, and I would send you for disrespect for the author’s work for a long time in the banned.
Without any arrogance and prejudice.
Send a complaint about the tester to the seller from whom you bought it and there is no need to make a complaint here!

[Stan21]

Don't cry, lion!

[madires]

Where is a link on 'two genuine OSHW firmwares' update instruction?

In case you're familiar with programming AVRs via ISP:
- https://github.com/madires/Transistortester-Warehouse
- or you could try a pre-compiled k-firmware at https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk (mega328_T3_T4_st7565 or mega328_T4_v2_st7565).

FYI:
- For example, DER EE DE-5000 is an LCR meter. There are huge differences between an LCR meter and a DMM able to measure capacitance and inductance. The DMM won't let you select a test frequency and it won't give you the Q factor. As a beginner it's easy to fall for marketing hogwash.
- The firmware of the T4 tester is based on an old version of the k-firmware. Because of the limited flash size of the ATmega328 the vendor had to remove some code and features to be able to add fancy graphics.

[Stan21]

Where is a link on 'two genuine OSHW firmwares' update instruction?

In case you're familiar with programming AVRs via ISP:
- https://github.com/madires/Transistortester-Warehouse
- or you could try a pre-compiled k-firmware at https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk (mega328_T3_T4_st7565 or mega328_T4_v2_st7565).

OK, so in brief, this model cannot be re-programmed without removing display, that is, without almost complete disassemble. And there is no proof that firmware update might help. And there is no warranty it won't brick after firmware replacement. Totally does not worth an effort.
Well, for my $15 I spent on this useless toy I had a lot of fun. Dumping.
Should I have asked you to lecture me about the semantic and definitions of 'LCR' term I should have thanked you  for the lot of totally useless details. Fortunately, I had not so I will not, sorry. But nice try, though.

[bitseeker]

Well, for my $15 I spent on this useless toy I had a lot of fun. Dumping.

 

Should I have asked you to lecture me about the semantic and definitions of 'LCR' term I should have thanked you  for the lot of totally useless details. Fortunately, I had not so I will not, sorry. But nice try, though.

 

[bitseeker]

@madires

Thanks for keeping your composure and trying to help. Unfortunately, not everyone can or wants to be helped.

[Hydron]

I'd like to second the thanks to the helpful people here, in particular madires and indman.

The fact I can go and buy such a useful instrument (and then improve it with the new firmware supplied here) for so little money is really amazing, and would be even more important for those starting off in electronics or with limited funds.