Build a Curve Tracer Circuit board.
Added 2017-10-02 01:53:12 +0000 UTCHere is a circuit board for you to build. This circuit board project involves many of the "breadboarded" circuits we built together in past videos. This is an incredibly useful piece of test gear that we will be installing into an oscilloscope in the near future. I will explain how to understand what you see on the scope screen as well. Congratulations, you're now building your own test gear!
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This is video #26, include this when requesting attachments.
Comments
Hi, where would I find links to get pcb designs that I could print out? Thanks
Jeff Petrick
2025-05-26 00:56:02 +0000 UTCI'm a bit late to the party but..... If you switched to the high current setting, did it improve the trace you are getting?
Keith-DS
2024-02-08 14:22:26 +0000 UTCPaolo Gramigna 16:04 I found a way to send you an image of the double trace: postimg.cc/MMTG79G3
Paolo Gramigna
2023-03-12 15:11:35 +0000 UTCI still have a problem: the curve is somewhat doubled, and it seems that there is a retracing while testing a Zener diode. Same as for a normal silicon diode. It appears some sort of hysteresis. Is that normal?
Paolo Gramigna
2023-03-12 14:49:50 +0000 UTCI have built the complete curve tracer. The voltage on my DMM was a bit low, so I modified the PCB adding a trimmer and a 470K resistor as in the peak detector schematic (previous video) and it worked.
Paolo Gramigna
2023-03-12 14:46:37 +0000 UTCGreat work
LoSaYa
2022-10-11 22:28:13 +0000 UTCI have a Huntron Tracker, but I'm still going to build your design too. I really do appreciate what you are doing here.
Tim
2022-04-06 04:52:40 +0000 UTCI just got done building this circuit. I can adjust the oscillator VR to 13volts. When I put my scope in XY mode I get a straight line and the gain seems to be working but the probe does not pick up anything also the calibration VR don’t move the line at all.
Beau Scarbrough
2022-01-30 04:54:08 +0000 UTCAre you will to release a gerber file of the PCB?
Rick Berg
2022-01-20 15:50:10 +0000 UTCWell, that was interesting - my build went OK, although I too had to substitute the lamp with a 2174. I did, however, notice two issues; my peak detector was reading low and my oscillator was showing crossover distortion - not something you expect to see out of a TL074 The answer of course, is that it wasn't a REAL TL074, and my TL072 was also counterfeit. Don't trust cheap IC orders from ebay, folks! Dropped some parts from a reputable parts house in there and it straightened it all out no problem. Next step will be fitting it with a dedicated power supply and a case I can stuff in next to my oscilloscope :D
SarcasticNameHere
2021-11-13 18:35:01 +0000 UTCsorry to say, not at all, its not the cheap or portable part, it's the digital part, you would need an analog oscilloscope, no post processing, most "real time" acquisition...analog rules! :) CORRECTION: I was thinking of complex lissajous patterns(oscilloscope music) that would look very "foggy" and unclear on a digital scope but for regular curve tracer use it would work fine except, and this is the answer useful to you, analog or digital, it has to have an XY function.
Andu
2021-08-20 15:50:43 +0000 UTCHello. Did you get any answer to your question? I am wondering the same thing
Tiberiu P
2021-06-04 19:37:08 +0000 UTCAre those cheap portable oscilloscopes from aliexpress good enough to be used with this curve tracer?
Vane
2021-05-11 13:56:24 +0000 UTCThe new old stock TL072CN IC's arrived and are preforming well. As I am putting my curve tracer in a box, rather then into a oscilloscope I added a cheap panel voltage meter. It arrived in 2 wire 4.5 volt to 30 volt form. Removing a zero ohm link and adding a third wire converted it to run from 0 volts to 30 volts. However when used directly at the output it was loading the output and dropping around 0.2 volts. I remedied that by making a few changes to the PCB in order to use the spare op-amp of the TL072CN as a buffer. It works a treat! :)
Broxie
2021-02-27 13:20:29 +0000 UTCHello, I am finally building this. I was unable to buy the TL072CN at the normal suppliers as it is obsolete. I substituted a TL072CP which is still available. The peak detector using that device runs fine initially from +/-15V supply, though after running at +/-17.5V for a short while it runs quite some way under. Eventually I moved the peak detector off onto a bread board to test a few more TL072CP, they all preformed similarly. I then used a external TL074CN on a bread board and find the Circuit works great! I have ordered so new old stock TL072CN from a auction site. Hopefully they will perform as expected. If not then I will use the TL074CN on its own little peak detector pcb. It is all going into a little box so I can hook it up to my oscilloscope (Rigol DS1054) form time to time.
Broxie
2021-02-22 21:00:25 +0000 UTCThat's a good question! Did you ever get an answer to the problem?
miaulon
2021-02-17 21:36:02 +0000 UTCHi, I've just finished this project and since I live in Europe in Czech Republic, there was no way for me to get the lamps Mr Carlson used. So I ordered some random small 40 mA bulbs (6V, 14V And 24V) And two out of three worked perfectly for the curve tracer. So I would suggest you to try and find out yourself. I don't think anything will go wrong with the circuit, if you use a different bulb. I don't have the equipment to measure the distortion of the sine wave, but on the oscilloscope my sine waves look nice and smooth. Good luck building it. Honza.
Jan Mezuliánik
2021-01-09 20:03:21 +0000 UTCHello Mr Carlson. I've just finished building this project, but there is a minor issue. I had to use quiet a long cable for the Hi/Low sensitivity switch (about 25 cm) a therefore (I think) there is a slight capacitance showing on the screen all the time (especially in the low current setting). Is there a way to compensate for this capacitance?
Jan Mezuliánik
2021-01-09 18:20:40 +0000 UTCHi Paul , Finally getting to build this curve tracer. Will the 7387 lamp be okay in this circuit? Have some of them from building the low distortion signal generator.
Kenneth Graham
2020-11-14 06:25:02 +0000 UTCHello Mr Carlson.I'd like to ask You to always make designs with through hole pcbs... Here in Brazil is too difficult to find smds components...and when this occurs the price is through out the roof..., besides to import from other countries is expensive a lot, due tax and dollar exchanges...
Robert G Leitao
2020-08-16 01:01:52 +0000 UTCI am loving Mr. Carlson's Lab! This curve tracer looks very interesting but I do not have a scope yet. Is there anything useful for these "handheld" scopes like the DSO188? My first guess is no, but is it possible that one of those could be used as a curve tracer with this project?
Glen England
2020-05-17 21:41:49 +0000 UTCHi Russell. Use polys in the oscillator circuit, and Tantalum's on the supply. Before ordering your caps, measure the lead spacing and compare to your choice at digikey. If the leads are a bit to big, they can always be bent to fit the board.
Mr Carlson's Lab
2020-05-06 22:44:13 +0000 UTCWhat are the best type of cap to use in the oscillator circuit on this build. I see the ones you used on the board are much smaller than those used in the testing with the breadboard. I had purchased a bunch of the larger ones and only found 2 that matched out of 12. I do purchase most of my components from Digi Key so any recommendations I can get would be appreciated. Stay safe in the crazy time.
Russ
2020-05-05 18:29:32 +0000 UTCHi Chris. Projects on this platform are for you to build, not PCB houses. If you look in the list of video's, you will find information on how to build your own PCB, it's very easy.
Mr Carlson's Lab
2019-10-22 01:52:45 +0000 UTCHow did you guys make the PCB? I do not have the means!, knowledge to etch my own. Is there a gerberfile or will JLPCB just take the pdf?
Chris G
2019-10-22 01:07:25 +0000 UTCI have not found one either. which TL074"s are required? IN, CN, BCN, ING4?
Jim Goodberry
2019-08-13 15:02:59 +0000 UTCHi. Very new to electronics. I have completed populating my very first PCB (on second try😉) thanks to Mr Carlson’s videos and excellent teaching skills. Really enjoying the course. I need some help troubleshooting display on Rigol 1054z xy setting I have re soldered, switched out components etc and I am now at a loss on what to do next. I am unable to see any horizontal gain when turning VR 4 as per alignment procedures. What I have checked so far: . Frequency is ok at 1006 hertz . Peak detection circuit working as DMM matches oscilloscope at 13 volts Can anyone assist in where I should look for problem. Sorry for long post, Thanks Brian
Chipset
2019-06-15 01:58:02 +0000 UTCIs there a component list for this project? I swear I haven't seen it yet LOL...
Joshua Hamilton (HamiltonMechanical)
2019-06-01 13:51:42 +0000 UTC...but... ...but... I *like* drilling holes! ...especially if the drill bit is nice and sharp! Haha
Bruce Dow
2019-04-23 17:49:25 +0000 UTCManaged to obtain the "rare as hens teeth" 7380 lamps over here in the UK . Imported from the USA for a whopping $42 (£32). Ouch!!
Keith Forward
2019-02-28 08:13:13 +0000 UTCWill do, thanks Greg
Keith Forward
2019-02-09 06:58:17 +0000 UTCKeith, you could try a digikey part # CM7381-ND for the 7380.
Greg Arikian
2019-02-09 04:21:23 +0000 UTCKeith, you could try a digikey part # CM7381-ND for the 7380.
Greg Arikian
2019-02-09 04:18:52 +0000 UTCHi Paul, I'm building the curve tracer and +/- 15v power supply. Would you please inform me as to the amount of power needed. My bread board will deliver 110 mA. need I up it?
Greg Arikian
2019-02-09 04:16:24 +0000 UTCHere in the UK the 7380 bulb is as rare as "hens teeth" so impossible to locate along with the 150VR. Their hugely expansive to purchase from the US so my build is on "indefinite stop" at the moment. Any alternative suggestions for components, apart from relocating to the USA would be appreciated.
Keith Forward
2019-02-05 09:51:50 +0000 UTCHi, going to build one of these, do you know where I can get those nice big pcb mounted variable resistors you're using ?
Jason Gill
2019-01-31 14:49:28 +0000 UTCJust so you know, the bulb is part of the wein bridge oscillator circuit and can't be replaced by an LED. It isn't meant to be used as a light source or indicator. Paul did a video about it and laid it out on a breadboard. Check it out! He used a couple of different bulbs. You can get them from digikey for a buck each.
Michael Gobell
2019-01-24 02:04:44 +0000 UTCI'm getting ready to make this, and the power supply which goes with it. Digikey didn't have the bulb, and I decided I'd like to use an LED instead. Is the portion of the circuit around the bulb just for setting the voltage for it? I'm trying to figure if I can alter that part to lower the voltage, and add a current limiting resistor. I'm making mine on perfboard with all thru hole components, and I have BNC jacks to allow simple connection to my scope. It's definitely more expensive doing it this way, and including the BNC cables, I'm at about $60. So I'm hoping I can use an LED which I already have and save from having to buy the bulb on eBay. To me, it's well worth $60 to have a way of troubleshooting devices which I can't get schematics for.
SwapPart
2019-01-11 19:29:13 +0000 UTCHello Paul, I'm thinking of building this device into a small form factor to be connected to and powered by the USB port on a modern digital scope and have 3 questions: 1) Are you planning to release a PCB in SMD design? If yes, when? 2) What is the +/- current draw of existing thru-hole design? 3) Any concerns with existing circuit to digital scope? Fantastic channel ans thank you in advance.
Sai Leung
2019-01-02 21:00:48 +0000 UTCAwesome Cory! You're welcome.
Mr Carlson's Lab
2018-12-13 09:23:39 +0000 UTCPaul. can the curve tracer be used to test laser diodes? say 780nm out of cd players? Thanks, Cory.
CORY KUEBER
2018-12-12 13:21:25 +0000 UTCAdriaan, use 107 ohm and 600 ohm in series and 6k and 1.07k in series. I purchased them at Digikey.
CORY KUEBER
2018-12-12 13:19:48 +0000 UTCHi Paul. Need some ideas to make up the 707ohm and 7,07k value resistors. These aren't standard values where I'm from. Great project!!
Adriaan Diedericks
2018-12-11 19:50:00 +0000 UTCPaul, My curve tracer is up and running! Thank you very much for this great circuit!
CORY KUEBER
2018-12-11 19:17:13 +0000 UTCStand down, I have now learned how to adjust the range on my scope. :)
Andrew Pratt
2018-12-11 17:55:13 +0000 UTCHi Paul, I am able to display a circle while testing caps in the range 10nF to about 2uF. Below 10nF I am getting an open circuit (horizontal), and above 2uF I am showing a short (vertical). Does this seem right? All electrolytic. Thank you.
Andrew Pratt
2018-12-11 17:42:20 +0000 UTCHi Mark. Make sure your scope is set correctly to read peak volts. Make sure you don't have any unneeded bandwidth filters on. Make sure your IC's are genuine TI parts, or equivalent quality. Lots of fake IC's floating around out there that perform horribly. Its a peak detector, and should have no error.
Mr Carlson's Lab
2018-12-10 23:03:37 +0000 UTCPaul a follow-up to my prior post... I brought the supply voltage down to 15volts as specified on the alignment sheet. The results were better but still a little off. The peaks on the scope were at the 13 volt level but showing 11.5 volts at the peak detector. Perhaps I'm heading in the right direction.
Mark Oriano
2018-12-07 16:22:52 +0000 UTCPaul I just finished up with the build and started the alignment... I applied 17.5 volts (pos. & neg). The sine wave is approx. 15 volts peak just before clipping however my voltage at the meter indicates 9.717 volts. I measured the voltage with my scope at pin 5 of the TL072 (peak detector) and get approx 15 volts peak there as well. I know the components are good ( diode, resistors, caps ). I tried four TL072 that I received a couple of months ago and all do the same thing. This doesn't seem to be to complicated but I'm scratching my head. Is it possible that all the TL072 chips are defective or is it something that I'm missing.
Mark Oriano
2018-12-07 01:36:49 +0000 UTCDear Mr. Carlson.
Michael K Tubbs
2018-12-02 08:44:45 +0000 UTCHi Cory, Linear is your friend, but Log is ok too. Yes the resistance is correct. The bulb is very specific too, use only whats specified.
Mr Carlson's Lab
2018-11-24 03:56:32 +0000 UTCPaul, Should the pots be linear or audio taper. Is VR1 really a 150 ohm pot? Thanks, Cory
CORY KUEBER
2018-11-24 03:06:14 +0000 UTCSimon, see my reply to "robotwizard" below.
Garth Wood
2018-11-14 20:52:51 +0000 UTCSingle-chip may not be readily available in a configuration that us benighted hobbyists can easily work with. There are some discussions on the web about making a "tracking ±15 volt power supply" using two LM317s and one LM337. Both chips are still readily available and cheap. The most expensive component could end up being the small line transformer. Google "lm317 +lm337 +"Dual tracking regulator" " for some links. Good luck!
Garth Wood
2018-11-14 20:43:12 +0000 UTCThe 1468 regulators are obsolete. does anyone know of a source for them? Or is there an alternative chip that will work?
robotwizard
2018-11-12 06:54:18 +0000 UTCHi , Where can I get the 1468 regulator chip from ? I am in Vancouver Canada atm . I come from the UK , not a problem over there . Thanks Simon .
Simon Murton
2018-08-22 19:03:27 +0000 UTCHI Toby. Those connectors would be fine to use. The frequencies that are traveling through the cables is low, so any shielded cable will work.
Mr Carlson's Lab
2018-07-09 04:28:37 +0000 UTCRegarding connecting circuits to scopes, Pomona has these very nice PCB format BNC's <a href="https://www.digikey.ca/product-detail/en/pomona-electronics/4578/501-1370-ND/1762485" rel="nofollow noopener" target="_blank">https://www.digikey.ca/product-detail/en/pomona-electronics/4578/501-1370-ND/1762485</a> ; they're marked 50Ω. Are they the right choice for connecting to high impedance probe inputs? What type of coax cable do you recommend? (BNC-BNC)
Toby
2018-07-08 19:40:45 +0000 UTCHi Toby, they are all there. I just downloaded them as a test. All is good.
Mr Carlson's Lab
2018-07-08 11:33:01 +0000 UTCHi Mr Carlson: Looks like the attached files here are no longer accessible.
Toby
2018-07-08 04:29:21 +0000 UTCWow! Another great video. I'm waiting your next video building the display. Thank you again sir.
Escabusa Roy
2018-06-28 09:13:29 +0000 UTCTake your pick, just make sure it's a dip package.
Mr Carlson's Lab
2018-04-28 19:31:36 +0000 UTCGood Day Sir! Which TL072 and 074 did you use? There are 7 different ones available on Mouser. Thanks!
Michael Crean
2018-04-28 17:09:11 +0000 UTCHi Paul, I know I'm a little late to this project, but is there a consolidated BOM for the latest rev of the project? If not I can go from the circuit board parts placement. Thanks
Jason Doerr
2018-04-28 00:38:50 +0000 UTCHi Mikael.
Mr Carlson's Lab
2018-04-27 04:46:37 +0000 UTCI may make some in the future. Another board design for this project is coming very soon.
Mr Carlson's Lab
2018-04-27 04:46:19 +0000 UTCDo you ever plan to make these boards available commercially? I am not a real fan of etching my own PCB's. As you know, there are many programs that could be used to distribute your designs such as Designspark or Fritzing. These are modern methods of distributing ideas that were only dreamed about when I was a much younger man! LOL! This project is terrific!!
Mikael McLeod
2018-04-26 05:58:18 +0000 UTCHello Paul!
Mikael McLeod
2018-04-26 05:49:53 +0000 UTCHi Merritt, here is an example drill bit set with the conversion numbers, I don't have anything to do with the seller, so this is for reference only: <a href="https://www.inventables.com/technologies/pcb-drill-set" rel="nofollow noopener" target="_blank">https://www.inventables.com/technologies/pcb-drill-set</a>
Mr Carlson's Lab
2018-03-14 20:47:09 +0000 UTCOnce again I'm late to the party. On your drill selections for the holes in the board, you show a .050 diameter drill. This doesn't match any number, fraction or metric drill size, so I'm assuming this is not a regular drill size. In looking, I've seen "router" bits with a 1/8" shank and .050 diameter bit. What are you using?
Merritt Derr
2018-03-14 11:15:12 +0000 UTCI look forward to seeing the outcome Tom!
Mr Carlson's Lab
2018-03-10 21:32:05 +0000 UTCExcellent project Paul! I have been into electronics since I helped my Dad build a HeathKit Amplifier, Preamp, and FM Tuner back in the mid '50's. I have NEVER heard of such a thing as this in all these years! I'm planning on transplanting the external board to a TM500 frame if I can find a dead module not worth fixing, or a blank module. Schematic is drawn in KiCad, and board layout to come, along with modifying my newly acquired laminator. More on the laminator in another post.
Tom Thornton
2018-03-10 19:45:48 +0000 UTCI would like to build this, but do not really want to do a new layout of the board, can spend the time better.
Sarel Wagner
2018-02-19 08:58:35 +0000 UTCNo terminations needed Dennis. Better to use the scope in X1 mode with this.
Mr Carlson's Lab
2018-02-19 08:15:37 +0000 UTCHi, I want to make this as a separate unit with BNCs to connect to the scope with coax. Would the coax need to be 50 ohm terminated at the scope? I am not sure the op amps could drive the load if it were terminated. I am not sure I did the thermal calculations right, but looks pretty borderline to me driving into 100 ohms, or will this be OK? Maybe output to a 10:1 voltage divider and run the scope in 10x mode?
Dennis Cabell
2018-02-18 21:55:15 +0000 UTCHi Paul, enjoying tremendously. A question pease? I am using a Laser system to etch painted PCBs. It can only import DXF files. Would it be possible to get the file in DXF from you please?
Sarel Wagner
2018-02-17 11:43:05 +0000 UTCDo you Think you could give us the pcb negative layout as well , for all those who use the negative photo resist to produce circuit boards
Garry Norbury
2017-12-18 15:00:19 +0000 UTCHi Clayton. You can experiment with bulbs, the more signal bounce at turn on, the lower the distortion. In order to suggest a substitute, I would need to do the same thing you have to do, that would be "experimentation."
Mr Carlson's Lab
2017-12-18 00:38:00 +0000 UTCI’m having issues sourcing the 7380. What would be an easily sourced substitute?
Clayton Moore
2017-12-17 13:42:31 +0000 UTCHi Julio, as long as the positive and negative Voltages are the same, +-12 for example it will be ok.
Mr Carlson's Lab
2017-12-09 14:34:50 +0000 UTCHello Paul, Could I get away with using 12 volts negative voltage for the curve tracer circuit? It’s all I can get from my power supply. Also, will this circuit work with a digital oscilloscope? Sorry for all the newbie questions and thanks in advance.
Julio Torres
2017-12-09 03:50:30 +0000 UTCVery nice looking scope Julio. That would definitely be a good device to own. At 200Mhz, 1Gsa/s, you're set!
Mr Carlson's Lab
2017-11-14 09:53:37 +0000 UTCHello Paul, Can you please recommend a decent oscilloscope model for a beginner. Looking to buy a used unit and have seen a few on Ebay but feel a little apprehensive about buying one from them. I’m looking to spend about 400 dollars for one. What your take on this one? <a href="https://www.amazon.com/Siglent-Technologies-SDS1202X-Oscilloscope-Channels/dp/B06XZML6RD/ref=sr_1_3?ie=UTF8&qid=1510621149&sr=8-3&keywords=siglent+oscilloscope" rel="nofollow noopener" target="_blank">https://www.amazon.com/Siglent-Technologies-SDS1202X-Oscilloscope-Channels/dp/B06XZML6RD/ref=sr_1_3?ie=UTF8&qid=1510621149&sr=8-3&keywords=siglent+oscilloscope</a> Your time and input is much appreciated and thanks for all the great videos.
Julio Torres
2017-11-14 01:08:57 +0000 UTCHi Barrie. I find some modern scopes just don't perform well in XY mode, (I own one) Some times using the averaging function clears this up a bit. If your scope has a "vectors" and "dots" display function, switch back and forth between the two, to see which gives the nicer display. Let me know if this helps.
Mr Carlson's Lab
2017-11-10 10:54:09 +0000 UTCG'day Paul Wondering if you can shed any light on a small issue I have. I built the curve tracer and I use it with a Rigol DS1102E oscilloscope. I have found that in XY mode the scope trace is broken up, almost as though it is made of dotted lines. I assume that this is a function of the speed of the trace scan and I'm wondering if there is anything you know of which may improve the visibility of the trace, other than buying a more expensive scope of course. The way it is makes it quite difficult to make measurements with any precision. Cheers
Barrie Davis
2017-11-10 01:57:02 +0000 UTCI had quite a bit of trouble getting this working or the breadboard version for that matter but it came to life yesterday, the low current side anyways. I think the problem was the dodgy AliExpress parts I was using. Once built I looked at dozens zeners I have. Basically all the cheapo ones looked like wheelchair access symbols while the ones sourced from reputable sources all had sharp knees. I think the lesson here is obvious!
Dennis
2017-11-06 22:12:45 +0000 UTCHi Micheal, its an older program called "Traxmaker 2000 Pro" A real comfortable program to use.
Mr Carlson's Lab
2017-10-28 03:55:18 +0000 UTCHey Paul, I know you had a video covering the software you use but refresh my memory, what's the name of the software?
Micheal Double
2017-10-27 05:06:46 +0000 UTCPaul is clearly a gifted teacher. Why he's not on the faculty of a major university I'm sure I don't know.
Rod Smallwood
2017-10-18 09:13:52 +0000 UTCThanks Michael! Lots of tube projects are in the plans.
Mr Carlson's Lab
2017-10-11 09:14:52 +0000 UTCI don't see why not. I think Paul was going for an option to make it accessible without special equipment. As far as I know you could replace everything in the schematic left of the 10k resistor connected to VR4 with a function generator.
1-800-STUPID
2017-10-11 03:51:59 +0000 UTCBTW, Paul you are the reason I'm now working on tube electronics now. I'm truly amazed how much I've learned from your videos. I've been EE for 30 years now and regret not being involved in tube circuits earlier. I'm currently getting my test bench ready for a full restore of a Stewart-Warner 72CR26. Thanks for letting me see the light. Pun intended. Hope you don't stop with the tube projects. Would love to see a retrofit of an old tube radio to act as a local AM transmitter. Including the tuning dial determining the xmit freq.
Michael Benoit
2017-10-10 17:07:03 +0000 UTCI do have a question regarding the design of this signal tracer. Could an option be to use your bench waveform generator instead of the on-board oscillator? Would reduce parts. But also understand the value of one less piece of equipment to use.
Michael Benoit
2017-10-10 16:51:42 +0000 UTCHi there. In the uk I have two spare 7380 bulbs/lamps available. These are not readily available in the uk. If anyone would like one let me know. £2.00 plus postage.
john smith
2017-10-10 16:34:48 +0000 UTCThanks Mark!
Mr Carlson's Lab
2017-10-10 08:06:10 +0000 UTCFor $2/month? We all need to advertise for this Patreon. I've never seen anything like it.
Mark Bosse
2017-10-10 00:36:50 +0000 UTCI really like that old scope. It's a little slow to boot up, but other than that, all is great.
Mr Carlson's Lab
2017-10-06 03:00:38 +0000 UTCJust watched the "junkbox scope" vid and ... there it is! In service! Not in a landfill! Doing real work! Very nice.
Peter Laws
2017-10-05 19:17:49 +0000 UTCNot yet.
Mr Carlson's Lab
2017-10-05 08:01:25 +0000 UTCAny schematics for dual rail power supply for this project?
William Phillips
2017-10-04 13:36:35 +0000 UTCDown the road, if there is enough interest, I will design a curve trace with a "step generator" or staircase generator.
Mr Carlson's Lab
2017-10-04 10:38:25 +0000 UTCI was wondering if you were going to include a ramp generator so we can test transistors Paul. Of corse nothing to stop us doing ourselves.
Diabolical Artificer
2017-10-04 06:12:43 +0000 UTCInstall a socket so you can swap different IC's, give it a try.
Mr Carlson's Lab
2017-10-04 02:11:46 +0000 UTCHi Marek. The 56 Ohm resistors are not on the board as this will be used in multiple applications (directly installed into the scope) or in a project box. If you put this in a project box with BNC outputs, you would install the 56 Ohm resistors from the board to the center of the BNC connector. In a higher impedance application with no coax run,, the resistors may not be necessary.
Mr Carlson's Lab
2017-10-04 02:09:19 +0000 UTCCan I replace the TL074 replace with LT1491A?
Marek Tomczyszyn
2017-10-03 20:48:05 +0000 UTCHi Paul in the final schematic the 56 Ohm resistors are not included in H-out and L-out. I thought they were there to match the 50 Ohm coax?
Marek Tomczyszyn
2017-10-03 19:03:39 +0000 UTCHi Steve, Try Arrow Electronics <a href="https://www.arrow.com/" rel="nofollow noopener" target="_blank">https://www.arrow.com/</a> I purchased 2 7387 T-1 3/4 Bi-Pin Incandescent Lamp for 1$1.50 and 2 7328 for $1.05 This company may be what your looking for. Bruce W2BBI
Bruce Isaacson
2017-10-03 15:54:14 +0000 UTCHi Ralf! I would like to see your surface mount creation, please do share it in the community section. Thank you for your kind comment as well!
Mr Carlson's Lab
2017-10-03 10:11:32 +0000 UTCHi Hunter. The Stackpole pot's I have used are just parts on hand. Feel free to use any suitable replacement. You can replace the "trace rotation" pots with extremely small units, as the Current at this point is very small. The pot in line with the bulb will have to be larger, as it deals with Current. You can cheat though :^) Use a random pot of around 150 Ohms, tune the pot for "no clipping" as mentioned in the alignment, once this point has been found, remove the pot without disturbing the shaft position, measure the resistance of the pot when removed from the circuit and replace it with a fixed value resistor. If you go this route, go a little past the point of "no clipping," so for example: If you find that no clipping occurs at 13.33 Volts, take the amplitude into a safe zone, say 12.9 Volts. This way you have a little room for temperature variation with your fixed value resistor.
Mr Carlson's Lab
2017-10-03 10:06:02 +0000 UTCThank you for noticing Lou! Thank you for your kind words as well!
Mr Carlson's Lab
2017-10-03 09:27:03 +0000 UTCThanks Paul, where is a good place to buy VR's. The blue ones seem so cheap and not like the stackpole minipot's you mentioned. Is there such a thing that is a step down from the stackpole minipot's. Thanks.
Hunter carmouche
2017-10-03 00:43:41 +0000 UTCMinimum order quantity of 100 for $99 at digikey and $8 shipping or $0.75 each at mouser but $20 for shipping... This is my first circuit, I suppose there is no cheap hobby... I don't want to buy locally, they charge $2 for 3 resistor. Hard...
Steve Beaudoin
2017-10-03 00:16:49 +0000 UTCAwesome circuit I am going to have to order parts and get it built looking forward to this one.
Zenwizard
2017-10-02 22:22:43 +0000 UTCIs there a cheeper alternative for lightbulb, also will the " more accurate" bulb mentioned in the earlier video work?
Cleveland Prescott
2017-10-02 21:44:44 +0000 UTCSorry to hear the sad news Paul, I wish you and yours well in a difficult time. Really appreciate the fact you have still taken the time to keep continuity with the great lessons - a very selfless act. All the best, Lou
Lou Lwin
2017-10-02 21:19:19 +0000 UTCThanks for your kind comment Andre!
Mr Carlson's Lab
2017-10-02 20:22:12 +0000 UTCThank You Tom!
Mr Carlson's Lab
2017-10-02 20:16:25 +0000 UTCThanks Paul, Glad to see you're back at it. How is you family doing, hope they are alright. This is going to be a nice project and as Reb said it would be nice to build this in SMD. Thanks again.
Andre Gopee
2017-10-02 17:33:44 +0000 UTCMy prayers go out to you and your family, Paul. I don't know if you are a person of faith but if you are, I pray for God's peace and love to be poured out over you and your family. Thank you for all that you do for the electronics community and may this be a long lasting and fruitful endeavor.
Tom Bilello
2017-10-02 17:02:56 +0000 UTCThank you Paul, this was much effort! Especially, I like the schematic which is very clean. I think about building this in surface mount in a couple of days, because I have to finish the current project first and I've never used surface mount trimmers. Have to find out howto solder those. Again, many thanks for sharing this!
Reb Elba
2017-10-02 15:47:35 +0000 UTCThanks for taking the time to write Walter!
Mr Carlson's Lab
2017-10-02 13:01:52 +0000 UTC<a href="http://www.huntron.com" rel="nofollow noopener" target="_blank">http://www.huntron.com</a>
Walter Anderson
2017-10-02 12:02:26 +0000 UTCHi Paul: Thanks for this very interesting tracer circuit. Your user of the word "signature"is interesting as well. HP used to make a signature analyst for circuits that attempted to assign an digital value to a circuit node. The algorithm for the circuit analysis was not known, and technicians used the device in troubleshooting as a way to comparatively analyze inputs and outputs of sections of a device to confirm proper function. Also, yes, Huntron still exists. I live 5 miles from their HQ, and have a friend that has worked for them for over 35 years!
Walter Anderson
2017-10-02 12:01:42 +0000 UTCThey are an older VR. Their name is "Stackpole Minipot"
Mr Carlson's Lab
2017-10-02 09:44:12 +0000 UTCNice little circuit lets see how it goes when I get ot the point where I can get it built...Thanks
Victor Miller
2017-10-02 04:44:18 +0000 UTCI like those VRs, do you have a part number/name/something to google for them?
Dennis
2017-10-02 04:03:12 +0000 UTCYes man Barrie i am sending also all my positive vibes for you to get better , this is very bad not being able to use our hand , my father is in that situation and he is getting more depress each time i meet him ! Man getting old is a drag for most of us .
Ramcur
2017-10-02 03:50:55 +0000 UTCThanks Ramcur!
Mr Carlson's Lab
2017-10-02 03:49:23 +0000 UTCHi Rod. I would have to say that this has been probably one of the toughest months in my life. My Mother passed away, and there has been much to deal with on my end. Thank you for your concern!
Mr Carlson's Lab
2017-10-02 03:49:08 +0000 UTCHey Paul ! the most interesting part is that you will tell us" how to understand what we see on the screen" . I am under the impression that a curve tracer is interesting for matching transistors ( because datasheet ) ,, but what is a matched pair , matched for what value , and why ! How to match pnp and npn together . I woud not mind listening to you for hours rambling randomly about transistor , what make them good transistor , for witch application is best suited that transistor . Hi-fi transistor is that a thing . what are the misconceptions about transistor . etc etc etc . the act of making a curve tracer is awsome , but your knowledge about transistor is way more juicy !! i think .
Ramcur
2017-10-02 03:43:58 +0000 UTCHello Paul - I trust your family situation has resolved itself for the better.
Rod Smallwood
2017-10-02 03:38:58 +0000 UTCHi Dave. The parts are clearly displayed on the schematic, and in the video. The only thing left for you to do is count.
Mr Carlson's Lab
2017-10-02 03:24:21 +0000 UTCHi Barrie, don't feel alone on this topic, this affects myself as well. The trick is to steady your hand through the tweezers on the circuit board. So while your holding the component to be soldered with the tweezers, put down force on the tweezers to the circuit board to steady your hand. Another way to steady yourself is to put your tweezer holding hand on a roll of solder, or the like. So picture a fist holding the tweezers (tweezers between your index finger and thumb) that fist on top of a roll of solder, or the like, tweezers holding the component to the board.
Mr Carlson's Lab
2017-10-02 03:21:46 +0000 UTCI'm looking for the usual type of BOM list. R1, R2, C1, C2, U1, U2 with associated values which makes it easy to determine with parts I have on hand and what I need to order.
Dave Negrych
2017-10-02 03:19:05 +0000 UTCHi Dave, download the schematic, all the parts are there.
Mr Carlson's Lab
2017-10-02 03:04:32 +0000 UTCHi Paul I really enjoy your videos and your expertise and I will build the curve tracer you have designed. One point I would like to make. You expressed quite strongly your preference for surface mounted technology and I might share it, were it not for the fact that as I get older I have developed quite shaky hands. This has become enough of a problem that with very few exceptions I will only work on through hole projects now. I appreciate that I am considerably older than you and this may not be a problem for a lot of your readers. Nonetheless you might spare a thought for the older members of your audience for whom this is a real consideration,
Barrie Davis
2017-10-02 03:04:09 +0000 UTCDo you have a bill of materials?
Dave Negrych
2017-10-02 02:56:02 +0000 UTCYou're Welcome Dustin!
Mr Carlson's Lab
2017-10-02 01:58:24 +0000 UTCThanks! Looking forward to making this this week!
Dustin Pundt
2017-10-02 01:54:10 +0000 UTC
