$20 LCR ESR Transistor checker project

[madires]

Yes Led powerd on, shows hundreds of scribbles

Have you also updated the EEPROM?

[upsss]

Hi, I need some expert help.  So far I mastered the flashing of new firmware on my tester (LCR-T4).  Now I am trying to figure out how to compile the firmware.

I am using the transistortester-trunk.tar.gz as the source code and the WinAVR-2010110 for the compiler.  Recently I received from Tom666 new firmware version LCR-T3,4_v1.12k_r660_ENC13 with the rotary encoder enabled and that firmware works perfectly on my tester with a rotary encoder.

I was trying to recompile the firmware with the Makefile that was included with the above firmware as an exercise.  During the compilation the program was 105.6% full and the new hex file size is 96KB compare to the original hex file of 83KB.  When I try to flash the new firmware I created I am getting Error: address0x8010 out of range at line 2049.  Any idea what is wrong?

Thanks

[tom666]

During the compilation the program was 105.6% full and the new hex file size is 96KB compare to the original hex file of 83KB.

You need update a compiler:
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg825078/#msg825078

[upsss]

Hi Tom, it works perfectly now!  You have been a great help! 

I wish there would be some sort of a "sticky" to answered common problems and questions.

Give a Man a Fish, and You Feed Him for a Day. Teach a Man To Fish, and You Feed Him for a Lifetime!

[nowlan]

Hello, considering getting one of these ESR kits to build. Had a look on bangGood, and there are a few to choose from.
Can someone recommend the darling? Is bangGood best bet, or aliexpress/ebay offer better ones or prices?


M328 LCD 12864 Transistor Tester DIY Kit Diode Triode Capacitance LCR ESR Meter $22.85au
http://www.banggood.com/M328-LCD-12864-Transistor-Tester-DIY-Kit-Diode-Triode-Capacitance-LCR-ESR-Meter-p-1041588.html

DIY M12864 Graphics Version Transistor Tester Kit LCR ESR PWM $25.67 (cant see difference)
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html

DIY M12864 Graphics Version Transistor Tester Kit LCR ESR PWM With Case $31.58
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-With-Case-p-997023.html
is the case worth $9 more. Seem to recall allignmnt issues.

GM328A Transistor Tester Graphic Wave Signal LCRRLCPWMESR Meter Inductance $20.44
http://www.banggood.com/GM328A-Transistor-Tester-Graphic-Wave-Signal-LCRRLCPWMESR-Meter-Inductance-p-997582.html

DIY Multifunction Transistor Tester Kit For LCR ESR Transistor PWM Signal Generator M328 $15.53
http://www.banggood.com/DIY-Meter-Tester-Kit-For-Capacitance-ESR-Inductance-Resistor-NPN-PNP-p-929603.html

[Votality]

Hello, considering getting one of these ESR kits to build. Had a look on bangGood, and there are a few to choose from.
Can someone recommend the darling? Is bangGood best bet, or aliexpress/ebay offer better ones or prices?


M328 LCD 12864 Transistor Tester DIY Kit Diode Triode Capacitance LCR ESR Meter $22.85au
http://www.banggood.com/M328-LCD-12864-Transistor-Tester-DIY-Kit-Diode-Triode-Capacitance-LCR-ESR-Meter-p-1041588.html

DIY M12864 Graphics Version Transistor Tester Kit LCR ESR PWM $25.67 (cant see difference)
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html

DIY M12864 Graphics Version Transistor Tester Kit LCR ESR PWM With Case $31.58
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-With-Case-p-997023.html
is the case worth $9 more. Seem to recall allignmnt issues.

GM328A Transistor Tester Graphic Wave Signal LCRRLCPWMESR Meter Inductance $20.44
http://www.banggood.com/GM328A-Transistor-Tester-Graphic-Wave-Signal-LCRRLCPWMESR-Meter-Inductance-p-997582.html

DIY Multifunction Transistor Tester Kit For LCR ESR Transistor PWM Signal Generator M328 $15.53
http://www.banggood.com/DIY-Meter-Tester-Kit-For-Capacitance-ESR-Inductance-Resistor-NPN-PNP-p-929603.html

Glad I'm not the only one bewildered by all the variants. Question is which one is the best.

[mauroh]

There are several other variants actually and you can decide to build it following the schematic online or just buy a fully assembled device, you can have it with input protection or color display...
The best is the one that better fit your need.
Yes, I hate when someone use this sentence... If I knew my needs I was not writing on a forum... 

Seriously, to keep it simple, the first 3 you linked are the same. I choose the one with the case, as for me it worth it and the entire unit is very nice.
The last one is just an old version with 2 row LCD (I don't like this).
All the above are DIY but really easy to put together and all the components are really easy to replace (also the microcontroller) that you will easily destroy with a not discharged cap  BTW you can add input protection.

The remaining one is fully assembled, all the parts are SMD but it do not have the encoded that is nice to have to easily navigate trough the menus.

Again it is up to you to decide, but i'm really happy with this:
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-With-Case-p-997023.html

Mauro

[upsss]

I would pick this one if you can build it, it's a real KIT. 

M328 LCD 12864 Transistor Tester DIY Kit Diode Triode Capacitance LCR ESR Meter $22.85au
http://www.banggood.com/M328-LCD-12864-Transistor-Tester-DIY-Kit-Diode-Triode-Capacitance-LCR-ESR-Meter-p-1041588.html

If you cannot built it then look for one already assembled with a Rotary Encoder.  You can find all of them on AliExpress a few dollars cheaper.

[bitseeker]

I'm surprised that there are so many on Banggood now. I got mine there some time ago and there was only one seller of the 12864 version. It was on sale at the time, so I bought it there rather than the other usual locations. I prefer the rotary input for better usability than a single pushbutton.

I initially wrote what mauroh did, but he hit the Post button before I did, so I'm trimming out the rest of what I had here.

(snip)

Regarding the case for the 12864, I didn't get it because I'm not keen on its aesthetics and dimensions. Personal preference, I'd say.

Finally, I'd stick with models that have a socketed Atmega328 microcontroller just in case you fry it, unless you're adept at replacing SMD ICs.

[mauroh]

At first glance I was not taking the case, because with the case you will lose the green ZIF socket an the SMD pads, but I managed to keep the ZIF easily cutting the case and now I can use the super useful tweezers (bought separately) also for in-circuit testing and for SMD parts.

For the SMD components with 3 pins I made a simple adapter with a cutter but someone made a better adapter.

Mauro

[upsss]

Where did you find the blank adapter boards?

[mauroh]

Not my design, I found it on an old post of the german forum where the autors of the current firmwares are really actives:

http://www.mikrocontroller.net/topic/343407

As I stated my version is much more "doggy", see picture 

Mauro

[kapuchy]

Hi everyone,
I am going to use "Atmega328P 5V 16 MHz Arduino Pro Mini" as 2x16 LCD tester with these steps:
- remove original AREF capacitor and use smaller value 1 nF,
- connect LCD module, test button + resistor (PD7) , 2,5 V reference (PC4) and 6 resistors 1%,
- rebuild Markus 1.21 classic project to 16 MHz clock (WinAVR 20100110).

Should I do something additional?
Should I use ISP programmer (ISP connector + USBasp) or original Arduino bootloader via USB/RS232 TTL dongle?

[madires]

I am going to use "Atmega328P 5V 16 MHz Arduino Pro Mini" as 2x16 LCD tester with these steps:
- remove original AREF capacitor and use smaller value 1 nF,
- connect LCD module, test button + resistor (PD7) , 2,5 V reference (PC4) and 6 resistors 1%,
- rebuild Markus 1.21 classic project to 16 MHz clock (WinAVR 20100110).

Should I do something additional?
Should I use ISP programmer (ISP connector + USBasp) or original Arduino bootloader via USB/RS232 TTL dongle?

You could also use 1.21m trendy edition. Anyway, you need an ISP programmer since the Arduino boot loader will be overwritten. There's an Arduino version of some older m-firmware and a shield (Ardutester), but I don't know if that project is still alive. Maybe also add a rotary encoder?

[upsss]

I just added a relay for input protection on my LCR-T4 tester.   Upon careful examination of the suggested circuit in the originator's manual, I see a major design flaw of the relay driving circuit. 

The relay is driven with a bipolar transistor from the TL431 2.5v reference voltage through a 4.7k resistor.  The transistor base current would be (2.5-0.7)/4.7k=0.38mA.  To drive the transistor into saturation, the transistor collector current would be only 0.38*10=3.8mA.  You cannot find a 5v relay that will operate at <4mA!  The most sensitive small dip relay that I could find had a coil resistance of 167ohm which will draw 30mA at 5v.   Most other small relays I found, drew more than twice that.  Even if you could find a 5v relay that drew <4 mA then you could not sink the additional 0.38mA from the 2.5v reference and keep it within specs.  The TL431 needs a minimum of 1mA and without the extra base drive it barely meets it (2.5/2.2k=1.14mA).

Your best bet for the relay driver is using a small N Channel MOSFET like 2N7000 driven from the 5v.  If you insist on using a bipolar transistor as a driver, then drive it also from the 5v and not from the 2.5v reference and use a base resistor of 1k not 4.7k which will support relays that draw up to 45mA.  If your relay draws more than 45mA then you will have to decrease the base resistor even more.

[GBowes]

Edited now that I am fully awake.....
The MCU obviously cannot pull PC4 up to 5V with the TL431 attached, so my original explanation was incorrect. I was a little to quick to explain that the suggested circuit works just fine as designed and my explanation was not correct. 

As Marcus pointed out, the error in your calculation is the hfe of the NPN. I don't think you could find a gp NPN with an hfe of only 10 and surely not a BC547.
A look at the data sheet indicates that typical characteristics would be that a collector current of 60 mA  would require a base current of a little more than 250uA

If your relay requires this much current you might want to consider connecting the collector to Ubat instead of Vcc as it is possible that the relay load would pull Vcc down during the measurement and significantly impact the measurement accuracy.

I have this installed as designed on three different testers and all works just fine with a gp NPN.. I think I used PN2222 or 2N3904 which can drive most any small, common relay.
Graham

[madires]

I just added a relay for input protection on my LCR-T4 tester.   Upon careful examination of the suggested circuit in the originator's manual, I see a major design flaw of the relay driving circuit. 

The relay is driven with a bipolar transistor from the TL431 2.5v reference voltage through a 4.7k resistor.  The transistor base current would be (2.5-0.7)/4.7k=0.38mA.  To drive the transistor into saturation, the transistor collector current would be only 0.38*10=3.8mA.

It won't work if your NPN only got a hFE of 10. A BC547A has 110-220, the B version has 200-450.

[upsss]

The hFE you are talking about is NOT for VCE(sat).  The hFE of 100-450 is specified at VCE of 5v-10v depends on who is the manufacturer of this BC547. 

The hFE for VCE(sat) on this BC547 is specified at 20, most common transistors in the US like 2N3904 and PN2222, the hFE for VCE(sat) is always specified at 10.  Even if you use hFE as 20, you still don't have sufficient base current to activate the relay.

[spiderb]

Hi all
I have the banggood DIY kit and have played with the Xtal test software.
I enabled 16 mz and it worked ok, I had changed the Xtal on the board
If I enable the WITH_XTAL option it starts up after programming but wont start after turning the power off
It will sometimes start after repeated presses of the button but sometimes the display is corrupted
If I disable the WITH_MENU option and leave the Xtal option enabled
it starts up every time, but I have noticed the screen for no component found
is corrupt, reading "N" on the top line and "damaged part" on the second line and the big question mark
The software came from the main site and was compiled and loaded with WinAvr-20100110
from the Yadi disk site.

I realise this is beta software and was wondering if anyone else had the same issues

Bill

[madires]

The hFE you are talking about is NOT for VCE(sat).  The hFE of 100-450 is specified at VCE of 5v-10v depends on who is the manufacturer of this BC547. 

The hFE for VCE(sat) on this BC547 is specified at 20, most common transistors in the US like 2N3904 and PN2222, the hFE for VCE(sat) is always specified at 10.  Even if you use hFE as 20, you still don't have sufficient base current to activate the relay.

Rule of thumb:
  I_b = I_e / hFE (non saturated)
  for saturation use 2 or 3 times I_b

Example (relay 40mA, hFE 200):
  40mA / 200 = 0.2mA
  2 * 0.2mA = 0.4mA

Please breadboard it and check what happens.

[upsss]

With all due respect, "rule of thumb" are not part of any manufactures specs.  That is why EVERY bipolar transistor has a VCE(sat) specified at a specific Ic and Ib.  BTW, I am an EE with over 30 years of hardware design experience and I never heard this rule of thumb.

[madires]

With all due respect, "rule of thumb" are not part of any manufactures specs.  That is why EVERY bipolar transistor has a VCE(sat) specified at a specific Ic and Ib.  BTW, I am an EE with over 30 years of hardware design experience and I never heard this rule of thumb.

I'm looking at Fairchild's datasheet of the BC546/547/548/549/550 right now. Figure 1 depics the diagram of V_CE vs. I_C. There's a curve for I_B = 0.4mA. Let's go for I_C = 40mA (our relay) and we'll find a V_CE of about 0.7V.

[upsss]

Any curves on datasheets are typical and are not guaranteed at all.  Any solid design should be based on clearly specified parameters, especially the saturation region of a bipolar transistor which is very murky on these charts.  My point also is that it really doesn't cost you anything extra to do it right.  Sorry if I am being a little harsh.

[CustomEngineerer]

With all due respect, "rule of thumb" are not part of any manufactures specs.  That is why EVERY bipolar transistor has a VCE(sat) specified at a specific Ic and Ib.

Which are listed as typical values, not absolute, guaranteed values, and can vary from transistor to transistor of the same batch.

Any curves on datasheets are typical and are not guaranteed at all.

As are most values listed on the datasheet. You sound like you think saturation is a single specific operating point, controlled by a single specific input value.

My point also is that it really doesn't cost you anything extra to do it right.

Says he who is not doing the work. Others have stated that the design works for them. If you can't figure it out you are free to implement it however you like on your board.

[Meth]

I've had one of these for a while now and they are just great - thanks to all involved!
The unit I bought was a GM328A pre-built unit with the larger display for under £12 delivered, performed the rotary encoder mod and flashed the open source software.

I've got a couple of request for features that might be useful - I did build them in to my own unit but it would be nice if they were officially supported.
These may be supported but weren't in the build I'm currently running (~550)
1) Pull the SVN revision out to the screen at either boot or in the menu system - the software changes so quickly I forget which version I'm running!
2) When measuring a potentiometer display not only the wiper position but also the full range, or the difference between the two.

Thanks again!