For those who enjoy microcontrollers - another way of making a transistor tester is to have the microcontroller generate two PWM signals that are low-pass filtered into voltages. One voltage goes to an op amp for the base driver and the other goes to a collector voltage driver (LM317). Two more op amps are used to condition the collector voltage and collector current readings for the microcontroller's ADC. The ADC values are sent by UART as CSV text for a PC to record and plot. If you want to learn about building op amp circuits, this is sort of fun DIY project.

I've done this very same kit and put it into a sloped case too with connections for no less than 6 transistors at once and a 3P7T switch to compare them! Works like a charm. 😎 Just two tips: - Put a SPST switch to disconnect pin 9 of 4024. You'll get just the first 4 low traces in case the base current of the 8 traces by default may be too much for certain transistors. I've done it and it is quite handy. - Put ferrite beads in the wires connecting to the ZIF sockets to get rid of any possible ringing.

My brain is swollen, and it's your fault! I have learned so much from you, information is leaking out of my ears. thanks for all of your videos.

Thanks for sharing your efforts with your build, as well as the mods you did. About 4 years ago, I ordered the CT and PS combo from them, waited 2+ months, it never showed (and it never showed after that either) , thankfully I got a full refund Looking around at auction stuff, I found a Eico model 443, which has transistor curve tracer circuitry, AND, a diode/component test section that can check forward and reverse bias breakdown up to 1.4KV, as well as having A-B switching and sockets for small transistors AND TO-3 packaged items built into the front panel. The 443 had one strange fault, either factory or kit built, it had the connections to the calibrated bias pot for signal transistors wired inversely from what logical functionality would dictate, it took a little playing with it to realize that, and swapping the 2 outside wires on the pot fixed that issue, as well as finding one broke wire and replacing OOT resistors and aged caps I was glad, and lucky to go that route.

Oh, just had a thought, it would be cool to select 1 transistor and see what all 3 of your testers say about it .....cheers.

The way you explained everything totally makes sense to me. I’d totally buy your Books on Tape if you did like Electronics for Idiots. That said, I need a curve tracer. I’m going after your idea.

I just made the ckt with your well thought out mods. Very clean signals even with 6 inch leads to banana jacks. I eliminated the BNCs in favor of two unused probe leads I had lying around. Used Dupont connectors to header pins for the basic board connections. I had an OP37F so I used that with excellent results. I need to calibrate the 1X and then ensure the high power is 10X. I REALLY liked your explanation of the theory and promoted it on EVVblog. I intend to document the traces and voltages. This has a much smaller footprint and is more convenient than the BK 501A and Heathkit, if more limited. But it works well for most amateur uses. I kept track, and my final unit comes in at $125.

Very good Tony, nice work, well explained!

this is brilliant , thank you tony

Enjoyed the theory lesson.Thanks!

Brilliant! Many thanks 👍

30:52 - One cool mod would be to modify the oscillator to generate a true 'ramp' signal!

looking forward to making some time to watch this. i bought and built one recently. i was contemplating inquiring about if 4 ch scopes had dual x-y mode so i could build another one and superimpose the curves on one another.

Nice Tony, can’t wait

The light sabre schematics pointer is pretty cool Tony. 😁

Awesome, this is something I keep meaning to do and now I have some enthusiasm to follow you ! please can you put the schematic in the box as Windows screen shot is unreadable too low a resolution....cheers.

I like it! 😊

Perfect timing Tony! 3 days ago I ordered the kit with power supply, and a 15 volt transformer. Any chance you will have a BOM for the upgrades, and more detail for wiring the sockets?

🛶Thanks for interesting circuit-videos. Really enjoy watching&listening. /,,have nice weekend

You could try and slow the clock down to see if your little scope can handle the sample rate.

Hi Tony, WoW this is a beautiful job, like from the factory. Those indicators at the active input are great, with my Tektronix TR210 replica, after activating the rainbow input, both curves are displayed simultaneously, and I can scroll with one displayed trace - I can overlap them. Unfortunately, it can't display the step graph of the transistor, it doesn't have a step up generator - so I'm building something similar to you, but with a max voltage of 200V. Nice day 🙂 Tom

Funny thing happened to me on my way to this week's xratonyb video. I'm building one of these right now. I have the circuit boards mounted and just finishing up the machine work for the case. Now the question is do I do these mods... The scope traces for this version are much cleaner than any other videos I've seen on this kit and I really like the feature allowing comparing two transistors.

i bought one of these kits.... Great mods!! I was curious..., can you use this to test diodes?

Apologies Merry Christmas and Happy New Year.

Add an "octopus tester" mode for testing zeners, etc.

I guess there is no need, do to emitter resistors, but I'd like to measure some TO3 packaged transistors. Collector voltage 70v DC op-temp hangs around 140-150ish F. I've only seen the tek 575 or 577 have a jig for the TO3 package.

Does the fact that "collector current" is measured at emitter create any real problems? One could think that low beta values will be skewed due to the base current. Thanks for another fine video, Tony!

Question Tony have you ever used the 74hc93 JK flip flop ic chip and a R-2R resistor ladder assembly to build a stair step generator circuit? I’m now using the CD4024be seven stage counter ic chip and the R-2R resistor ladder assembly with this combination it yields a much better stair step wave form.

where did you buy this mounting box?

Tony on the scaling circuit could you have used a JRC4556 op-amp?

Tony I noticed that they are powering the CD4024be ic chip with a negative voltage power supply. Any thoughts on why they are doing this?

Another question. Is it important to have the frequency of the step signal and the Collector to Emitter frequency the same?

BOM? Please.

you going to release your schematics etc?

As we all are used to from @xraytonyb this is again a brilliant video. Agree totally to the points taken here and the video gave me a couple of good points to think and watch