Looking for a transistor tester

[fig]

For FET matching, I use this;

<a href="https://oshpark.com/shared_projects/tG4sSkqf"><img src="https://oshpark.com/packs/media/images/badge-5f4e3bf4bf68f72ff88bd92e0089e9cf.png" alt="Order from OSH Park"></img></a>

btw, the test unit from Amazon arrived today. I realized I had no 9v batteries about and was about to use the PSU when I wondered...would a draining battery affect the test results? Above my pay grade unless I can demonstrate it empirically (or one of you clue me in.

The TC-1 is on it's way and I'll compare them both to the DCAPro. I'm considering doing as Dan and including Mr. Keen's test rig. I'll try to share the results in some meaningful fashion. I am certainly open to advice or tips........there's a jar over yonder.

 

[fig]

I ran some comparisons between the TC1 which was purchased at StompBoxParts for $25, and the TaoBao (atmega328) purchased from Amazon for $21.69. I used the Peak DCAPro and Peak LCR45 for reference purposes only. This is not to say that the Peak devices are or are not more accurate. Seems the funding for this project was held up by those bastard bureaucrats (no offense Hermes) at the University of Mars in preparation for "Elon's arrival". Those ninnies were always suckers for celebs. Where was I? Oh yes, alone and flying blind!

Not the most scientific approach perhaps but it should give the reader at least some idea of what they get for their $

I tested a variety of components and all 3 devices were pretty close, with the exception the DCAPro measured higher gains on Ge transistors. The other two were very close to one another. I'll look into this further, as this can be a pretty critical measurement in some circuits and I personally would like to know if the DCAPro could be misreporting these.

Testing Ge transistor leakage is not available on the TaoBao from Amazon.

The clamp assembly on the TC1 is flush mounted and permanently attached, whereas the TaoBao must be inserted into what looks like a 4x7-hole breadboard, which is not stable and really defeats the purpose of having a clamp. I found it easier to leave the clamp assembly off and shove the component into the breadboard.

The TC1 has a rechargeable battery and comes with a USB charging cable. The TaoBao requires a 9v transistor battery.

The TC! also came with 3 mini-grabber test leads.

In like, my opinion man, The TC1 is a clear winner for an additional $3.31

 

[StompBoxParts]

We're big fans of the TC1! We have them all around the Cusack campus, great little tester for all sorts of things and super simple to use.

As discussed, it is not the perfect tester for germanium transistors. It will get you in the hFE ballpark (reporting higher from leakage). We'll sometimes use it as a second opinion or if we need to do a rapid test of a bunch of germanium. We use RG Keen's method as our primary test for sorting.

 

[SillyOctpuss]

Did the battery cover fit on TaoBao after a battery is inserted in your unit @fig?

 

[fig]

I didn't have one handy, so I used my bench supply. I meant to test that too! Hang on..

 

[Coda]

Did the battery cover fit on TaoBao after a battery is inserted in your unit @fig?

It fit on mine. I’m upgrading to the TC-1, though. However, the TaeBao has been working pretty well…just no leakage.

 

[SillyOctpuss]

It fit on mine. I’m upgrading to the TC-1, though. However, the TaeBao has been working pretty well…just no leakage.

I wonder if the one I had was a little thinner. There's no way a 9v was going to fit. I can't measure now though as I've already sent it back.

 

[fig]

Nope. Will not go on.

 

[fig]

Wait...I got it on there! Sheesh. I had to force the little tab down to do it!

 

[SillyOctpuss]

Wait...I got it on there! Sheesh. I had to force the little tab down to do it!

I kinda wish I still had mine here to measure the depth. There's no way a 9v was going to fit in the one I had.

 

[fig]

I'm sure the tolerances are pretty lax. I'm planning to open it up and poke around.

Edit: Okay I almost never got the door OFF again, LOL. So, nothing to see inside really (smd components and a mega328p), but I found if you loosen the two bottom screws slightly, the battery door fits better (on this one).

As for batteries, I don't really use them often, but when I do I make sure they are as mojo as well.
​

 

[StompBoxParts]

This is interesting to me as my personal tests, with a TC1 and breadboarded RG tester side by side, show striking parity between the two in almost every device I’ve ever tested.

That's definitely good news to hear. Curious.... similar readings for hFE or Iceo and leakage (or both)? I was testing a few hundred transistors last week and the readings were not the same. In the ballpark, but definitely not the accuracy we wanted. That said, it was a terrible batch, almost all unacceptably leaky and we ended up rejecting the whole batch as less than 20% were useful and almost none in any of the "sweet spot" gain ranges.

I'm going to take a guess that if the device is lower leakage it will show up more accurately on a TC1 side by side with RG. If you got from a good source, they probably already sorted out the leaky ones. I'll look a bit closer with low vs high leakage in mind when we get a different batch of AC128s in (any day now!!!!).

 

[Kroars]

Will that measure germanium leakage?

Not accurately (or perhaps hit/miss is a better descriptor). It’s great for quick measurements of caps, resistors and silicon transistors. I’ve got this one and the TC-1, they’re almost identical. The TC-1 turns on and tests a bit faster but they’re both great for what they do. I think the DCA55/75 is about the only thing that measures GE transistors anything near accurately aside from long form with a DMM.

 

[Kroars]

I'm sure the tolerances are pretty lax. I'm planning to open it up and poke around.

Edit: Okay I almost never got the door OFF again, LOL. So, nothing to see inside really (smd components and a mega328p), but I found if you loosen the two bottom screws slightly, the battery door fits better (on this one).

As for batteries, I don't really use them often, but when I do I make sure they are as mojo as well.
​

Not just mojo, but “Ultra” mojo!

 

[StompBoxParts]

That's definitely good news to hear. Curious.... similar readings for hFE or Iceo and leakage (or both)? I was testing a few hundred transistors last week and the readings were not the same. In the ballpark, but definitely not the accuracy we wanted. That said, it was a terrible batch, almost all unacceptably leaky and we ended up rejecting the whole batch as less than 20% were useful and almost none in any of the "sweet spot" gain ranges.

I'm going to take a guess that if the device is lower leakage it will show up more accurately on a TC1 side by side with RG. If you got from a good source, they probably already sorted out the leaky ones. I'll look a bit closer with low vs high leakage in mind when we get a different batch of AC128s in (any day now!!!!).

16 hours and 400 transistors later (with more to go), I've come to a few conclusions comparing the TC1 and the RG Keen method side by side....

-The TC1 is a snapshot of measurements, which means it will NOT catch an instable or excessively leaky germanium transistor. You need to see this over time with a multimeter. If the leakage and hFE keep going up and up and up, it is bad. A good transistor will read nice and stable within ~1-30 seconds.
-The TC1 does not do a good job with low gain transistors regardless of leakage. In my test, the TC1 method were nowhere near accurate, always displaying a higher hFE.
-Once there's some gain ~70 and up, and the instable and very leaky transistors are weeded out, the TC1 does a pretty good job at displaying an accurate hFE and leakage/Iceo. Which means if you bought good transistors pre-sorted from a reputable place, the TC1 will give you fairly accurate results.

 

[fig]

Awesome information sir, thank you for sharing. I see the Kliche´ kit is now available in your store as well.

(oh and thanks for the heads up on the new stock of transistors)

 

[fig]

I’m can’t pretend to test that many devices and my go to Ge device is the incredibly low leakage General Electric 2N169. Not the best data set from me!

Where are you getting 2N169s? Are those the pinch tops?

 

[fig]

Yeah, those are steady #s. I have a few in Steve's setups but I might get a few more.
I bought a group of MP21As and they are really consistent..(Iceo as well)

 

[Coda]

I want Ge transistors that are leaky. I got ToneBender and FuzzTones to build...

 

[peccary]

Leakage is not your friend! Leakage is like an unpredictable friend at a keg party.

What's a kegger without an unpredictable friend or twelve?