Author Topic: $20 LCR ESR Transistor checker project  (Read 1440709 times)

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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #50 on: March 16, 2013, 06:39:55 pm »
Anyone with high speed scope, please share the test signal please.

There's no need for high end gear ;-) Just check out the source code! Large caps are charged with pulses until a specific voltage is reached. Multiply the number of pulses with the pulse width and you'll have the time. Then use the famous equation for charging capacitors to get the capacitance.
 

Online BravoV

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Re: $20 LCR ESR Transistor checker project
« Reply #51 on: March 16, 2013, 06:46:58 pm »
Anyone with high speed scope, please share the test signal please.

There's no need for high end gear ;-) Just check out the source code! Large caps are charged with pulses until a specific voltage is reached. Multiply the number of pulses with the pulse width and you'll have the time. Then use the famous equation for charging capacitors to get the capacitance.
OIC, thanks Markus for the the explanation on the cap measurement method ! Its just I'm lazy to go through the source code !  ;D

As my question, so this thing can not be used on low voltage cap ?
 

Offline torch

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Re: $20 LCR ESR Transistor checker project
« Reply #52 on: March 16, 2013, 10:00:44 pm »
OIC, thanks Markus for the the explanation on the cap measurement method ! Its just I'm lazy to go through the source code !  ;D

As my question, so this thing can not be used on low voltage cap ?

You don't even have to decypher the source code. It's covered in the documentation that was posted on page 1 of this thread:

5.3.2 Measurement of big Capacitors
One side of the capacitor is connected to GND. The other side of the capacitor is connected with
the 680  resistor to VCC for a period of 10ms. Afterwards this probe pin is switched to Input (High
Impedance). After this 10 ms current pulse the voltage of the capacitor is measured without any
current. If the voltage has not reached a minimal value of 300mV, the load pulse is repeated up to
499 times. If after 127 pulses a minimum voltage of 75mV is not reached (about 2s), further load
is stopped, because never the 300mV can be reached with the remaining load pulses. Figure 5.21
shows the three phases of measuring the capacity value of a capacitor. The value of the capacity is
then computed with the count of load pulses and the reached load voltage from a table. The table
contains the factors to get the capacity in nF units from load time and the reached voltage with a
spacing of 25mV. Interim value of voltage will be interpolated.

Now I realize that VCC in this case is 5v, which is technically above the 1.8v you are concerned about. For all of 10ms. I don't really know much about such low voltage caps or if they are robust enough to take a brief pulse, but certainly the 6.3 volt caps are in no danger.

Personally, the highest voltage I saw on the scope during my own experimenting was about 3.5v, but I don't remember how big the cap was. It might well go higher with a low-value cap.
 

Online BravoV

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Re: $20 LCR ESR Transistor checker project
« Reply #53 on: March 16, 2013, 10:55:35 pm »
Unless I'm reading Spawn's scope shots wrongly and CMIIW, isn't that his test voltages are quite high ?  :-//
 

Offline Spawn

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Re: $20 LCR ESR Transistor checker project
« Reply #54 on: March 17, 2013, 12:42:10 am »
Yes indeed my scope reads around 8volts, you can see the volt/div switch on channel 1 at 2volts, probe is 10x Tek P6109. About the speed BravoV, I could go one lower in magnified situation to 5ns that’s the fastest it gets but the signal got so vague I couldn’t see where to put the cursors to measure something.

Other important thing I forgot to mention is, I had a fresh battery every time when you push the button it tests the battery, at the start it was 9.5volts after around 20 tests while I was trying to find good setting on my scope to get a waveform it dropped to 8.9volts. I am not sure how many tests you can do with caps, I could give a go on a fresh battery and average value cap to see that but then it will be waste of my 9volt battery  ^-^

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #55 on: March 17, 2013, 09:58:49 am »
OIC, thanks Markus for the the explanation on the cap measurement method ! Its just I'm lazy to go through the source code !  ;D

You're welcome! Who isn't lazy? :-)

Quote
As my question, so this thing can not be used on low voltage cap ?

The charging of any cap stops at about 1300mV maximum. And for large caps (>50µF) the current is limited by a 680 Ohms resistor (@5V), i.e. about 7mA. For small caps it's a 470k resistor.
 

Offline space_bastard

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Re: $20 LCR ESR Transistor checker project
« Reply #56 on: March 17, 2013, 11:28:07 am »
Awesome build! Just came across this diy ESR meter on Hackaday:

http://hackaday.com/2013/03/16/testing-caps-with-a-diy-esr-meter/

I have been looking for a cheap way to test caps, I may have to look into a diy solution!
 

Offline Radio Tech

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Re: $20 LCR ESR Transistor checker project
« Reply #57 on: March 17, 2013, 12:15:31 pm »
Awesome build! Just came across this diy ESR meter on Hackaday:

http://hackaday.com/2013/03/16/testing-caps-with-a-diy-esr-meter/

I have been looking for a cheap way to test caps, I may have to look into a diy solution!

I looked at the design today also.  And decided to build one. So tore down a couple of pc power supplies to rob the step down transformers out of. But ended up making 2 bench power supplies out of them.  :-//

Anyway ordered the one posted here in this thread today.

Offline notsob

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Re: $20 LCR ESR Transistor checker project
« Reply #58 on: March 17, 2013, 12:30:37 pm »
And here's an interesting one, by Fr Tom McGahee on his cap meter design, pcb pdf's and PIC code available (of course you'll have to modify the code for a later version PIC)
 

Offline space_bastard

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Re: $20 LCR ESR Transistor checker project
« Reply #59 on: March 17, 2013, 04:53:09 pm »
Awesome build! Just came across this diy ESR meter on Hackaday:

http://hackaday.com/2013/03/16/testing-caps-with-a-diy-esr-meter/

I have been looking for a cheap way to test caps, I may have to look into a diy solution!

I looked at the design today also.  And decided to build one. So tore down a couple of pc power supplies to rob the step down transformers out of. But ended up making 2 bench power supplies out of them.  :-//

Anyway ordered the one posted here in this thread today.

You can never have too many power supplies!  :-+
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #60 on: March 26, 2013, 04:13:02 am »
My new firmware 1.06m is released. New features are an improved UI, use of the MCU sleep modes to reduce power consumption (as in 1.06k) and a PWM generator. You can choose between several pre-defined frequencies in a menu and increase or decrease the duty ratio in steps of 5%. But beware :-) No ESR or L measurements are supported (if you need those go for 1.06k).

You'll find all firmwares and docs at http://www.mikrocontroller.net/svnbrowser/transistortester/. The m-version is located under Software/Markus.

Have fun!
 

Offline amspire

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Re: $20 LCR ESR Transistor checker project
« Reply #61 on: March 26, 2013, 04:07:56 pm »
Thanks Markus.

Any reason for removing ESR and L? Is this an issue of code space in the Atmega168 ?
 

Offline casinada

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Re: $20 LCR ESR Transistor checker project
« Reply #62 on: March 27, 2013, 03:52:13 am »
Markus,
Do you still offer compile code?
Thank you very much :)
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #63 on: March 27, 2013, 09:13:32 am »
Any reason for removing ESR and L? Is this an issue of code space in the Atmega168 ?

Never added those to my firmware fork :-) Some time ago when Karl-Heinz was adding the inductance measurement (k version) I also played with that but dropped it because the measurement range is very limited. Later Karl-Heinz expanded the range by running the ATmega out-of-spec for a short period of time (so far no ATmega died from that :-). The ESR measurement was similar and don't forget the odd test frequency. I don't think that there's much gain by ESR and L measurements with quite limited ranges. A dedicated LCR meter is much better for that. And yes, the ATmega168 is nearly maxed out.

PS: Karl-Heinz is improving the ESR measurement at the moment.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #64 on: March 27, 2013, 09:26:06 am »
Do you still offer compile code?

It's open source software and hardware. Nothing to hide :-) Karl-Heinz always creates a few precompiled firmwares for some common hardware
setups (for the lazy :-).

 

Offline Radio Tech

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Re: $20 LCR ESR Transistor checker project
« Reply #65 on: March 27, 2013, 10:31:40 am »
I got my tester in yesterday, but was too sick to play with it. I did get a chance to use it tonight. Very nice. I like it.

Offline casinada

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Re: $20 LCR ESR Transistor checker project
« Reply #66 on: March 29, 2013, 08:48:05 am »
Actually Lazy is one of my nicknames :)
I originally purchased the semiconductor tester from www.warf.com as it comes with a nice case. it worked well but it had a couple of bugs on the firmware. I purchased a couple of Atmega8 and and the USB ASP to be able to program the chips, download the pre-compiled software and programmed the chips with the AVR extreme burner. It worked fine but then I found out that Karl was working on an improved version of your original design so I purchased the other version of the component tester version 2.2 on exxy.com and also a couple of Atmega328 to play with. I haven't compiled for a long time. I come from a strictly assembly language background (z80, 8088, 6800, 8051, 68HC11) so here I am again downloading the WinAvr suite and trying to figure out how to use it. I just wanted to try your newest version of the firmware on my original design hardware. Yeah, It might take me a couple of nights to figure out how to compile the code ......... call me lazy :)
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #67 on: March 29, 2013, 10:14:50 am »
software and programmed the chips with the AVR extreme burner. It worked fine but then I found out that Karl was working on an improved version of your original design so I purchased the other version of the component tester version 2.2 on exxy.com and also a couple of Atmega328 to play with.

The original design was done by another Markus. I joined Karl-Heinz last year.

Quote
I haven't compiled for a long time. I come from a strictly assembly language background (z80, 8088, 6800, 8051, 68HC11) so here I am again downloading the WinAvr suite and trying to figure out how to use it.

Still got my 68HC11 developer board ;-)
 

Offline Radio Tech

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Re: $20 LCR ESR Transistor checker project
« Reply #68 on: March 31, 2013, 01:08:04 pm »
Blah, was going to use the new tester today for the first time in a real world test. Bloody thing failed to come on.  :palm: I only tested new caps out of the parts bin since I had it.  So today someone brought over a board with possible caps bad.  I said hey, let me show you thing neat gadget I just got. And it would not turn on   :-BROKE Boy did I feel stupid. Anyway I will give anything a second try. So I ordered another one.  |O

Offline amspire

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Re: $20 LCR ESR Transistor checker project
« Reply #69 on: March 31, 2013, 01:40:44 pm »
And it would not turn on   :-BROKE Boy did I feel stupid. Anyway I will give anything a second try. So I ordered another one.  |O
You didn't unplug the display, and then plug it back - but out by one pin? Easy to do.
 

Offline Radio Tech

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Re: $20 LCR ESR Transistor checker project
« Reply #70 on: March 31, 2013, 01:48:31 pm »
And it would not turn on   :-BROKE Boy did I feel stupid. Anyway I will give anything a second try. So I ordered another one.  |O
You didn't unplug the display, and then plug it back - but out by one pin? Easy to do.

Nope. Wish it had been that easy lol.  Thought maybe a bad battery. But it was good. tried another to be sure. Got voltage on the board but no display. The red LED will not come on either. Probably controller failure. When I get the cance this week I will do a bit more troubleshooting. The Ebay seller offered to replace it. Told him no worries I will just order another, so I did. Now I have one to tear down  :-DD

Offline kubi48

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Re: $20 LCR ESR Transistor checker project
« Reply #71 on: April 20, 2013, 05:00:00 pm »
Hello,
I would like to tell you, that a new version of my TransistorTester software is ready for download from the mikrocontroller.net site.
The main advantage of the new version is a improved ESR measurement, which can now determine ESR for capacitors with more than 0.18 uF. The new approach use shorter current pulses to measure the ESR.
Additionally this method can be used to measure resistors too. This gives a resolution of 0.01 Ohm for resistors with less than 10 Ohm and the calibration use this function to measure the zero resistance. So no more the extra calibration of ESR zero with big capacitors is required. In the majority of cases the new ESR measurement gives lower results because the shorter pulses make the result more like a 10 kHz measurement.
Additionally a new parameter is output for capacitors with more than 5000 pF and low quality factor. This parameter is the voltage loss (Vloss) immediately after a load pulse. Some older paper capacitors make problems to get the right capacity. The error can be more than 100%. Also other instruments have problems to measure the right capacity for that capacitors. For this type of capacitor a voltage loss of more than 10% was measured, so the TransistorTester gives you a warning hint with the Vloss now.

 

Offline amspire

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Re: $20 LCR ESR Transistor checker project
« Reply #72 on: April 20, 2013, 06:22:40 pm »
That's at http://www.mikrocontroller.net/svnbrowser/transistortester/Software/tags/ I guess. V107 is only 21 hours old.

Here is a Google Translate of the changelog:
Quote
Makefile option NO_NANO Specific activity complements.
Extended function GetVloss for capacitors with more than 5nF, previously 50nF.
The self-test Let's remove the short-circuit test at 4 is monitored, AllProbesShorted by Markus R.
The GetESR function is used during calibration to determine the zero resistance (pin-dependent).
GetESR function is also used for resistance values ??below 10 ohms.
Function GetESR replaced by new assembler function.
New feature GetVloss to measure the voltage drop after a charge pulse at small 45uF capacitors.
The GetESR function converted to assembler to make the time sequence regardless of the compiler optimization.
Assignment of Flash and EEPROM memory optimized.
BAT_POOR level changed in the Makefile to mV indication, indication of just 1.3V +0.1 V warning.
ESR measurement for capacitors from 0.45uF supplemented with 500kHz ADC clock.
The resolution of the inductance is set to 0.1mH Resistance 680 ohms.
The Pinreihenfolge with individual diodes is issued in accordance ATmega168/328 EBC_STYLE.
 

Offline torch

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Re: $20 LCR ESR Transistor checker project
« Reply #73 on: April 20, 2013, 08:16:53 pm »
Well this sounds intriguing!

I've never played with these AT projects. A quick google tells me there are a variety of ways to upload programming to these chips.  The Chinese board seems to have a 10 pin unpopulated header that might be the interface for the soldered processor. Can anyone confirm this?

Supplementary question: does this look like a suitable programmer: http://www.ebay.com/itm/USB-ISP-Programmer-for-ATMEL-AVR-51-ATMega-ATTiny-/200460739146 ?
« Last Edit: April 20, 2013, 08:18:36 pm by torch »
 

Offline kubi48

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Re: $20 LCR ESR Transistor checker project
« Reply #74 on: April 20, 2013, 08:59:33 pm »
The chinese board uses a 10 pin ISP header. The ISP interface is specified as 10 pin or 6 pin header.
I don't know anything about the quality of the ISP programmer with USB interface in your link.
 


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