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Identify base, collector, and emitter of transistor

davenn

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I have a small device with three leads that takes most of the skill of of it. Connect the device and press a button...

however with progress comes problems. It can identify ge and si devices but sometimes comes really unstuck on schottky diodes.

maybe the same as this one ?
http://www.peakelec.co.uk/acatalog/jz_dca55.html

semiconductor tester.JPG

I have one of these .... awesome bit of test gear to have in the shack :)

Dave
 

CDRIVE

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After Dave posted that I shot over to ebay to see who's selling what and if the Chinese were cloning it yet. Most of the models I found were not Chinese and were selling for ~$150.00. I didn't find anything that resembled a Chinese clone of Dave's and Steve's 'Peak'. I must say I was surprised. Peak is fortunate that it's not yet cloned because the Chinese will sell it for <$20.00!

On the other hand the current sales price makes it a viable DIY, as it doesn't fall into the ..I can buy it cheaper than I can make it category.

Chris
 

CDRIVE

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maybe the same as this one ?
http://www.peakelec.co.uk/acatalog/jz_dca55.html

View attachment 24369

I have one of these .... awesome bit of test gear to have in the shack :)

Dave

I should have done this before my last post but I clicked the video link on that page and it's really worth watching. For one thing it will give those aspiring to roll your own an insight to the parameters the manufacturer used. It will also give you a clear picture of its limitations. The narrator pointed out its limited ability to fully test JFETs. We'd have to fix that if building a home brew.

One thing is certain. If anyone takes up this project it's going to be the most design intensive project ever posted on EP! If successful it will also be the most popular! Oh, one more thing... Thyristors! It has to identify and test those too!

I think what intrigues me about this is it's the ultimate example of uC based "Black Box Analysis".

Chris
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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I think what intrigues me about this is it's the ultimate example of uC based "Black Box Analysis".

Not quite the ultimate.

Mine can't handle UJT's or very low Vf schottky diodes. It also mislabeled the anode and cathode of a 3.3V 1W zener diode. Mine is supposed to be able to identify SCRs and Triacs, but only if their trigger and especially hold current is very low.

The real advantage of a "home brew" one of these would be the ability to do software updates to add and differentiate between additional devices.
 

CDRIVE

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Not quite the ultimate.

Mine can't handle UJT's or very low Vf schottky diodes. It also mislabeled the anode and cathode of a 3.3V 1W zener diode. Mine is supposed to be able to identify SCRs and Triacs, but only if their trigger and especially hold current is very low.

The real advantage of a "home brew" one of these would be the ability to do software updates to add and differentiate between additional devices.

When I said "ultimate" I meant brewing one. I feel what you have is damn good but there's always room for improvement. The failings you and the video mentioned needs to be addressed.

To brew one that can really handle Zeners the DUT voltage would have to be increased high enough to handle most Zeners. I think an upper limit of 24 to 28V Zeners will cover most circumstances.

Waddia think?

Chris
 

CDRIVE

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Remember what I commented about the Chinese cloning? Well this is not a clone of what you have. It appears to be more versatile! You're going to cry when you see the price! It even does stuff yours doesn't. The 9V bat alone overcomes some of the issues you mentioned. It should handle Zeners to ~8V.

I'm an impulse Ebay buyer. When an item is under $30.00 I don't even hesitate. I'm ordering one now! It's limitations won't matter to me because whatever they are they will serve as a goals to overcome if brewing one proves practical.

Chris

http://www.ebay.com/itm/MK-168-TRLC...940004?hash=item21069e04e4:g:XKkAAOSwNphWYWVA

 

CDRIVE

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Please forgive me for successive posts but I find this topic exciting. For those following this thread here is more info and links to this technology.
This one has LCD graphics.
http://www.ebay.com/itm/MK-328-TR-E...pacitance-resistance-ESR-Tester-/121593935597
This one has LCD graphics too but also includes some history. It would appear that all of these concepts were born from an open source (still is) German project that's been cloned.
http://hackaday.com/2015/04/24/review-transistor-tester/

Chris
 

CDRIVE

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I hit paydirt and found the developer's PDF. It includes extensive theory of operation and schematics! The source code is somewhere else though.

Chris
 

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CDRIVE

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Further sleuthing proved positive. Well not exactly. The truth is I was googling to see if there was a crossover between any Picaxe chips and the ATmega8, ATmega168 and ATmega328. I didn't get a positive hit in that regard but I did find an updated (V1.06k) version of the PDF.

This PDF cleared up some of my confusion when viewing the later schematic, like the two dead ended conductors labeled "Button" and other labeled "Serial". The V1.04K pdf that I uploaded yesterday does not address these but the V1.06K does. The conductor labeled Serial connected to an unused SerialOut/ADC3 leg that's used to test higher voltage Zeners and also provide a Voltmeter function that the older design lacks. These are 2 pin tests only and does not utilize the 1 2 3 inputs.

V1.06K also describes additional protective circuitry using a micro-relay to be used on the 1 2 3 inputs. The relay contacts short all three 1 2 3 inputs prior to pressing the Test button. It's purpose is to discharge caps. This is a must for many of our members that like to party (Marty) and feel smarter for it. :rolleyes: It will save us from those moments when we do something stupid and then hate ourselves afterward!:oops: :eek::mad:

My guess is that Steve's and Dave's commercial model is based on the older V1.04K.

At this time the location of the latest (V1.06K) source code still alludes me but I'm still digging. It's supposed to be on SourceForge.org but they're currently down.

Chris
 

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  • CompTstr(V1.06K).pdf
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