#232 

I had no idea about curve traces until I watched a Mr Carlson's Lab, and once I saw that chart the operation of a transistor really solidified.

the way you educate others is really appreciable Mr.W2AEW , good going

This is so cool! As an undergraduate EE student i often get tired of such an intense course but your videos inspire me to carry on! Amazing stuff as usual. Thank you again!

Fantastic series. Really interesting and made easy to watch with your clear and effective explanation style. Thanks for making them.

Wow, such a complex circuit in such a simple way that even a non EE person can understand it. Kudos my friend!

Super educational circuit! It's great that it has a purpose too, but there's a massive value just in the fundamentals it demonstrates.

Brilliant video and always fantastic engineering content on this channel. One of my faves!

Circuits like this are a great way to teach electronics. Nice way to introduce transistor characteristics. Big thumbs up from me.

this is my favorite electronics channel. very well explained

These videos are alot of fun. You make my scope more and more valuable as I learn from these videos. I only wish I had your experience to design these circuits. Thanks!

I'm always happy to see your videos! They are very interesting and are explained very effectively! Thank you for your work.

Also, what I love about your teachings and schematics is that the different sections are broken up into pieces. I'm a software dev, and of course that's what we do, but never really thought about it for analog circuits. I'm starting to recognize different common patterns (even said to myself "current mirror" when first looking at it).

Excellent Explanation as always by Alan, Thanks a lot for your time and efforts.

damn we need a REAL practical electronics instructor like this at my school. good job on all your videos. i learn a lot from them.

Great video. A very neat circuit. Thank you for taking the time, I learn a lot from you.

Thank you Alan as always enjoyed and had my full attention. Great circuit to build and learn

That's cool! You could also use the stairstep generator to drive the lines on a CRT to make the scan lines !

This channel helped me learn a lot about electronics.Thank you sir

I'm going through an EE program right now, and your practical videos (with all the little tips and tricks from experience) are a boon! Keep up the great vids!

Really awsome video (as always). Please do much more of these.

Excellent! For a hobbyist like me, that's gonna be more than enough. Certainly better than just picking a pair of transistors with a similar gain at a fixed current.

That cut-out schematic "trick" is superb!

Well explained and simple circuit. Nice job.

Thanks again for another great video, Alan!

Curve tracers seem to have gone the way of the dodo, and any that you can find are the same price as a decent car, despite it being such a useful thing for people tinkering with basic electronics. I, for one, would love to see you design one from scratch, that would maybe be an advanced project, but doable for the average mortal who already has a scope. I find your tutorials so easy to follow that I would definitely try to build one.

Este circuito era exatamente o que estava procurando. Encontrei aqui por acaso..... kkkk...vou fazer este experimento. Obrigado por disponibilizar o circuito e colocar nele a referencia que o inspirou em fazer o experimento. (Brasil Português ) This circuit was exactly what I was looking for. I found here by chance ..... kkkk ... I'm going to do this experiment. Thank you for making the circuit available and putting a reference on it that inspires you to do the experiment. (Brazil language Portuguese)

Very nice Alan. Enjoyed the video. I have a old restored Eico 460 scope sitting around that I have been thinking about adding a curve tracer circuit to.

Many thanks Allen for this very instructive video. You would do me a great favor in continuing on with the ability to test pnp and p-mosfet transistors. Regards, RJM

nice video, there are certainly a number of ways to generate a starecase. I like the analog aproach since it is easy to alter the number of steps. Thanks and thumbs up!

Fantastic. So well explained and demonstrated. Thank you.

Thank you! Wonderful presentation.

Great!! it works for me, I'm not EE of any degree I just like electronics and study one year at high school some technical basics of electronics, back at my younger days, thanks for sharing your knowledge

Nicely done and explained. Thanks.

That's very informative and neat, many thanks for sharing.

Great video! Thank you very much! You are my "electronic" mentor :)

Great video. Keep them coming!

Enjoyed Watching the video. Thank you for sharing.

Cool! Very useful and thanks for waveform-explanation. Make more videos like this :)

Always learning-- Great presentation.. Thanks...

Big thanks for this nice impressive example.

Your schematics are really neat, it's like you're a human CAD program :) If i would draw that circuit you wouldn't recognise it

As always I learn things from you. I do electronic repair for a living I can think of a few occasions this could have been helpful. Wish I had taken college when I had the time and funds to do it. You should pursue this and design and build one for multiple voltages and types. A short video on how someone could modify it to be usable over a broad spectrum on transistors, NPN/PNP/MOSFETs etc. would be interesting for sure. Thanks for the Video. Best Wishes and Blessings Keith

Excellent as usual.

Thanks for this good educative video.

thanks it was an excellent presentation

I'm making this circuit at the moment, I have the stairstep circuit working I need to add some potentiometers so I have the option to set some variations. I want to be able to set the frequency higher and lower, now it oscillates at 185Hz exactly. I also want to be able to set the amplitude and if I can add the ability to input a DC offset that would be great. I'm also adding a switch with the resistor for driving the gate of a MOSFET and the resistor to ground so I can do both and don't have to change the circuit every time. First I'm making the circuit on a breadboard so I know for sure that it works with the components that I'm using and then I'll make it more permanent on a perf board and solder it all together. I already made a different function generator using two 555 timers that have the output synchronized but the second chip outputs the signal inverted. On that function generator I can set the duty cycle from about 20% to 80% at the moment so that could use some improvement, I can set the frequency from 1Hz up to about 450KHz, I can also change the amplitude of both outputs and all the settings work independent so changing one setting doesn't change the other ones. So when I have this circuit working I'm going to try and put all the different function generators together on one single PCB, it would be nice if I can use the timer chips and the op amps for the different purposes to keep the component count a bit lower but if I can't get it to work it doesn't really matter because I already have all the parts and those are pretty cheap but I don't want to use up everything I have for this function generator, if I can save some components I don't have to buy new ones when I want to start tinkering around and use it for something else. w2aew, your circuits took a long time for me to really understand what is happening but I've learned a LOT just from watching your videos and making the circuits myself, because there are some differences in the components that I'm using it was a challenge for me to get my circuits to work properly but as you already said it is the best way to learn this stuff. I wish you have a great day w2aew.

TNX for another great video !

beautiful ! and all analog. great stuff!

very good circuit, very useful

Great Presentation

fantastic, congratulations and THANKS!!!

great work bro

I was expecting a more exponential rise of the C-charge, but in this way (early cut-off) it it quite linear. Otherwise a simple current source would do a linear work. But maybe it doesn't matter at all, as we are plotting the resulting collector current on the y-axis, it really doesn't matter in what fashion the Vce is changing, as long as it is incremental, I suppose. We just get more or less points in some regions.... Once again interesting circuit 👍

جزاك الله خيرا ربنا زدنا علما

Simply wonderful.

brilliant video.

Very good presentation. Is the 270 Ohm resistor essentially the collector resistor that would be the load line of the transistor?

Nice work Alan, thanks. Man, I wish I could afford a scope like yours...

very satisfying to see the A4 punched holes lining up

10:15 "...if I was going to set out to build a curve tracer I probably wouldn't start with this..." Why? Is it unnecessarily complicated, inaccurate, or ineffective? What is the ideal design (or design elements to seek out) for someone with an entry level digital scope? I've seen #197 and #49, your two other videos on curve tracers. I probably don't "need" a curve tracer, but I feel like I learn a lot more about practical electronics by building circuits like this. Plus, no one complains about having too many tools to work on projects ;) -Jake

Alan,Great video, I kinda saw this one coming while watching video 231. None-the-less, I have a Tek 576 that is awaiting some of my free time to start heading up the learning curve (pun intended). This video is a great jump start. I'll bet drawing a load line should be made quite easy with the 576. Any hint/tips/kinks/suggestions are welcome. 73, W1SEX

That’s beautiful!

Great video

what a great video and presentation. I'm looking for a trans curve tracer used, I may build this, thank you.

Great video! I have a some questions: Is it possible to make it work as curve tracer for NPN and PNP transistors? What improvments can be done?

Good job. Thumbs up!

Fascinating...cheers.

thank you it is very helpful

You are a wizard!

Hi Alan. Could the linearity of the ramp generator be improved by using a current control transistor instead of the 100 kohm resistor? Of course, the linearity may be good enough as is for the job in hand. Another nice video with good illustrations and description; as well a good learning project for beginners.

I have the simulation in Proteus and it works for my, thanks. I am going to upload the video in my RU-vid chaanel

Brilliant, thank you

Can this circuit be modified to switch between NPN and PNP transistors? I'd also like to be able to test "power" transistors.Thanks for providing us with clear, concise, and understandable tutorials.

Thank you very much.

I love these general-purpose circuits-in-action videos, thanks! What's that "hole" in the plot on the lower gain transistor (9:34). Looks like the first few base currents aren't conducting till a much higher Vce than the higher base currents.

Mr Wolke, how should I adapt the schematic for non rail to rail op amps?

Nice circuit Alan. Like the presentation too. I like your jigsaw approach with the drawings, piecing them together as overlays. I have a question about the capacitor that is introduced with the second drawing, the one being discharged periodically with a transistor. You said the charge doesn't go near Vcc so the trace is the bottom end of the cap's charge cycle and is therefore rather linear, no problem with that but your trace has the capacitor charge flattening off just before the reset pulse arrives. If the cap doesn't reach Vcc and the Transistor isn't being driven then why would the cap flatten off nearly 40uS before the pulse. (Yes you can see this in HD, Visible at around 6:23)

EXCELLENT !!!

Brilliant!

Minimalist = cleverist. :) You mentioned matching toward the end; it occurred to me that it might not be that hard to add drive and "output capture" for a second transistor, subtract the currents, and... Bob's your uncle! Just a thought; I don't know if people do that sort of thing when they're trying to match transistors. Hope things are well with you!

Thank you for so many excellent videos. At 2:35 you mentioned that you make the base resistor large so that it acts as a current source. How does the particular voltage level act as a current source when Rb is very high? Is that just because the resistor translates a locally constant voltage to a locally constant current?

Anther great video.

one of the applications of this circuit is Stepped FMCW Radar (sweep voltage to VCO)

Very good

Pardon the dumb question, but I'm wondering about the current mirror you added to the circuit. Did you use general PNP transistors? I'm thinking 2N3906's. Though I am a real beginner, I find that the clarity of your explanations, drawings and demos are very understandable (though some require multiple views). Thank you for all your work. Finally, for your "Basics" videos, I would love to see something on how to chose between the many types of oscilloscopes available today. Also, a video on all the capabilities of your current scope (the MDO4104C and associated probes) would be very interesting.

You state in the Schematic Diagram, which is great I might add, that this circuit is based on one published in the 'IEEE Engineering Sciences & Education Journal Vol 8 No 1, Feb 1999 pp 25-26'. Do you know where I can get of a copy of this?

Nice circuit! Does it work for pnp as well as npn?

Hi can you make it to view the Negative region or negative resistances really great channel Thanks Allen

Could you do a video on how to match JFET's. Could this circuit be used for JFET's? Thanks.

Enjoyed your video Allen! Is there a curve tracer that sweeps from 60~ to about 10MHZ? When checking caps I need a higher sweep rate to read small caps, 10MHZ preferred for junctions of various transistors/diodes. I've been using 60~ over the years and its not giving me the coverage I want! Your circuit of "#232" is great but its an over kill vs the one I have at present. Thank you, 73's , Gary Grove CET

Could you use voltage from NE555 capacitor to drive X axis? Just add offset to op amp, and use it as inverting op amp. I think that shape of ramp voltage to drive collector doesn't affect shape collector curves. If it is exponential instead linear it just mean that it will sweep faster to start of curve than at end. But speed are low enough that it shouldn't affect curve shape. You still get collector current for applied voltage in every dot. EDIT: Great video, as always! Thanks

QUESTION: Is there not a fairly easy way to make this work with a PNP transistor? Made this stairstep circuit a while back and was going to build a transistor curve tracer and thought of this. Would really like it to work with PNP transistors also. And power transistors. Wasn't sure if this would work with them either. Love your videos! You explain things very well. Thanks!!

Perfect

Does it work with PNP transistors as well ? (newbie question)

Thanks Alan. I'd like to build a simple CT for bp's and fet's of all flavors. Could be an interesting video to modify this circuit a little bit more?

Cool stuff. How can we increase the Vce. 100V should be fine.

Hello, Excellent explanation. You used MSO. Is there any problem using DSO? Thanks

...and I thought your teaching skills were superb! Your schematic drawing skills are second to none. Forrest Mims has nothing on you :)

Great video, as usual. I saw a video where someone modifies a TekTronics 576 tracer, with a pad modified for use with tubes. Would something like this work in that situation - I'm looking to match some sweep tubes ffor the PA of an National NX3 and Swan 600T.

Sir, nice circuit .what is transistor used for current mirror and the last op amp no is not given .simple and usefull test for transistor