$20 LCR ESR Transistor checker project

[madires]

If that model got two unused pins and if T0 is also available then it should be possible to add the extended frequency counter. The next challenge is to make it small enough to fit into the case.

[juvann]

Looking at the schematics available online PB0 (T0) and other 3 pins are available
So I will buy and I will try the mod.
what will be the maximum frequency that can be detected?

Thank you madires for the help.

[madires]

I don't know the max frequency supported by the hardware of the extended frequency counter but for the MCU the theoretical limit is:
   f_max = MCU clock * prescaler / 4
(prescaler is 16 or 32)

[indman]

madires,are there plans future to add the SamplingADC function in your to doo list?
External additional modules are, of course, good and they expand the capabilities of the tester.But if it is possible to use internal reserves and processor capabilities for the same purpose, then why not?
This is аctual true for a small portable device.

[madires]

Back then when Karl-Heinz added PA3FWM's idea of the SamplingADC I had a look at it and my first thought was that it's an interesting concept. On the other side I'd prefer a proper LCR meter when measuring such tiny values. Weighing up pros and cons I decided to not implement the SamplingADC. But if someone likes to implement it for the m-firmware I wouldn't hesitate to add the code.

[indman]

But if someone likes to implement it for the m-firmware I wouldn't hesitate to add the code.

This is definitely a great motivation for those who want to thoroughly understand PA3FWM's code, but this task does not seem too easy to me. Maybe I'm wrong.

[coromonadalix]

I'm surprised to see the lack of mega 1280 - 1284  2560 series of arduino's  .... or diy  boards

With bigger display shield(s)  it could be evolved further without costing an arm

[indman]

coromonadalix What do you think this is? 
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg3119442/#msg3119442
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4504399/#msg4504399

[BroMarduk]

Not sure if this has been pointed out or not but there's a small bug in config.h

Line 2082 is where it starts:

This

Code: [Select]

/* variable Start_str */
#if defined (SW_OPTO_COUPLER) || defined (SW_DS18B20) || defined (SW_ONEWIRE_SCAN) || defined (HW_EVENT_COUNTER)
  #ifndef VAR_START_STR
    #define VAR_START_STR
  #endif
#endif
Should be:

Code: [Select]

/* variable Start_str */
#if defined (SW_OPTO_COUPLER) || defined (SW_DS18B20) || defined (SW_ONEWIRE_SCAN) || defined (HW_EVENT_COUNTER) || defined (SW_DHTXX)
  #ifndef VAR_START_STR
    #define VAR_START_STR
  #endif
#endif
At least that is the only way I can enable DHTXX without one of the others also enabled.

[Yuriy_K]

When setting up sampling_lc.c for the TTester on MEGA 2560, I noticed the dependence of low inductance readings on the connection to the inputs with direct and reverse switching. This dependence is also observed on other measuring instruments. See for yourself in the picture.

[Feliciano]

I don't know if that is an issue specific to the MEGA2560, but on other ctesters, I've noticed when I measure several times the same inductor --whithout moving it-- the results differ a little.

I haven't looked into the measurement subroutine, but maybe the method tends to let some remanent core magnetization. You may want to dig into that.

[madires]

The Transistortester uses DC for measuring inductance (standard measurement method, SamplingADC is a different story) while a proper LCR meter applies an AC signal.

[Yuriy_K]

I don't know if that is an issue specific to the MEGA2560, but on other ctesters, I've noticed when I measure several times the same inductor --whithout moving it-- the results differ a little.

No, the testimonies themselves are stable, all meaningful numbers. Indications have more value when connecting the lower output of inductance to the input "1" and less when connecting the upper output of inductance to the entrance "1". The method implemented in sampling_lc.c is very accurate. I only adjust it to the length of the internal compounds of the Mega 2560 in the range of 40 nH - 2 μH.

 Here is a fragment from ttester-1.13k en.pdf
"...Together with a parallel connected capacitor the inductor build a resonant circuit. With a
short current pulse this circuit begins to oscillate some times without further stimulation. With the
sampling method the frequency of this oscillation can be measured..."

[Feliciano]

The Transistortester uses DC for measuring inductance (standard measurement method, SamplingADC is a different story) while a proper LCR meter applies an AC signal.

Currently I have one WEI with K-fimware and one of the new T7 (not a 324) with Chinese firmware. IIRC, the SamplingADC is enabled for the first one, but I don't have both equipment in front of me to take some snapshots now.

When I measure some chokes or transformers, the first(s) measurement(s) gives me one value, and further measurements tend to give me different, but reasonable stable, values. That's why I think the measurement method perhaps uses more pulses in one direction than the other, therefore having some sort DC offset which in some cases is more noticeable than others. But you guys know the code better.

[Spongey]

I finally took the plunge and got a random version from eBay. From the outside this looks identical to the LCR-TC1 version but inside it has the same PCB as LCR-T7(FNIRSI) AFAICS complete with a (presumably fake) chip marked as MEGA328P.

When you power it up in test mode it says FNIRSI-TC1, pauses at 38% but it does not report the firmware version at the end.

I was hoping to reflash it, never mind.

[Yuriy_K]

I propose a new version of the addition of the TTester circuit for measuring quartz and ceramic resonators in the range of 100 kHz - 20 MHz. The Chinese version HCF4060BE with a supply voltage of 6V and the use of an internal divider, allows you to measure quartz up to 20 MHz. Malaysian variant up to 16 MHz. I did not manage to lower the frequency for sentries (32768 Hz).

P.S. I apologize for some texts in Cyrillic, while debugging...

[madires]

Firmware-wise it would be the extended frequency counter without the input selection. I could add it as a new counter variation.

[jemp]

Hello
Got 2 LCR Testers today from AliXpress..  New LCR-T4 and LCR-T7 Color  
Both have new firmware version 3.12K  
Does anybody know where to find this firmware.. or is it a hoax..  mean Chinese Variants.. ?

tnx for info

JP

[madires]

That's a modified k-firmware with fancy graphics and less features.

[indman]

New LCR-T4 and LCR-T7 Color 
Both have new firmware version 3.12K 

I'm not 100% sure, but these new firmware are protected for reading and are also designed for clones with Chinese-made microcontrollers. This is mentioned in my clone comparison table.

[Yuriy_K]

Firmware-wise it would be the extended frequency counter without the input selection. I could add it as a new counter variation.

To use the 4060 as a driver pre-amplifier, the following circuit must be applied. A multi-turn variable resistor will allow you to accurately set the maximum conversion frequency.

[jemp]

Hello, like in  #7908 I have also a MK-328 , with PCB 1.0 Date 2014/07/14
I programmed it with 1.13k..
Seems to be 2-3 versions.. with light fonts, or thicker fonts..
So programming no problem at all..
I works OK, starts up etc.. will do calibrate etc..  BUT....
I wont shut off ! when no component in it.. it goes blank and restart always again, automatically

Any thoughts ?

Does anybody has the ORIGINAL Firmware 1.11 ?

Tnx Jemp

[madires]

The k-firmwmare has a setting for power management called POWER_OFF (in the Makefile). What have you set for POWER_OFF? Or have you disabled it?

[jemp]

Hi Markus
I did not compile the soft myself for the moment
I just flashed firm 1.13k, like attachment in msg #7910-11 and following
No firmware whatsoever closes the Tester Down... it resets itself constantly..
Could be a hardware failure..?
But I measures OK and perfectly.. just wont power off , after certain time

[madires]

A common setting for POWER_OFF is 5, i.e. the tester will shut down after 5 consecutive "no part found" messages. You could also try to press the test button for a few seconds after the last result.