A $125 Curve Tracer that is functional - Page 1
Forum section: electronics / testgear

author: watchmaker
author_rank: Unknown
timestamp: February 28, 2024, 02:50:41 pm
content: I used the modifications suggested in the You Tube linked at the bottom.While I need my Ziff sockets and a switch, this is easier to pull out than the BK 501A.I used an OP937F for the vertical amplifier from the original board. This (with the calibration pot) makes 1mV equal 1mA. I need to play with the capacitor on the amp board to get rid of the tail.I will have two Ziff sockets to A/B; and each ZIFF will be set up to do EBC and ECB (front and rear locations).As you can see, it draws very little power; a total of 50mA. I want to protect the ckt on the secondary side of the power supply. Either 200mA fuses or a current limiter.In order to get rid of the BNC cables and connectors, I sacrificed 2 Siglent probes (I use Teledyne 10X) which will be permanently attached to the unit (sorry TauTech).As you can see, stray capacitance and noise are not an issue. Even when I use 150MM test clips. The trace on the Siglent is teriffic and more refined on the CRT.Excluding the cost of the lab, I thnk I have $125 into it. Or a complete cost of around $5125.Everything uses some form of quick disconnect to facilitate future mods and service. I am using a Jameco PSU for permanent power.This is limited to a max of 15V transistors. Also, for some reason, the hi current output is an odd multiple of the low current power. I may change it to 10X.Thanks to Tautech for teaching me how to use my scope; Tooki for helping me to improve my crimping, and especially the guy who made hot glue a tool.I plan to document all voltages and traces. It seems there can be problems with the basic kit. But it can work.The pics show the performance after being on all nite (accidentally). So it is stable. NPN, low power.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: February 28, 2024, 03:25:08 pm
content: Little context would be useful. Not everybody will go to the length researching your posting history to find the related other threads.

author: Kosmic
author_rank: Super Contributor
timestamp: February 28, 2024, 03:32:26 pm
content: Quote from: watchmaker on February 28, 2024, 02:50:41 pmHow do you get to 125$ ?the ThaiKits curve tracer is 24$ + shippinghttps://www.thaikits.com/index.php/measurement-testing-checker/ch-012-transistor-curve-tracer-adapter-xy-oscilloscopes-2-ranges-biasOnline%20Electronic%20Kit%20Store.html

author: mawyatt
author_rank: Super Contributor
timestamp: February 28, 2024, 03:32:44 pm
content: Nice workYou can use one ZIF socket and a switch to flip between Left and Right sides as is done on the Tek 577 adapter we did some time ago. The ZIF socket has enough contacts to do CBEC, ECB, DGS (Drain Gate Source), AK (Anode Cathode) on each side.You might want to include ferrite beads to the various ZIF socket pins to help reduce chances of parasitic oscillations with higher speed DUT devices.Best,

author: watchmaker
author_rank: Unknown
timestamp: February 28, 2024, 04:12:27 pm
content: Quote from: Kosmic on February 28, 2024, 03:32:26 pmHah. That is for starters.Basic Kit: $40 with shippingPSU: $35 (Jameco comeswith transformers)Amplifier board: OpAmp,trimmerpot,board) $10??Switches: $5Box: $20PowerCord jack with switch and fuse:$5Connectors: $10Banana jacks: $2Test leads with banana plugs and test hooks (just the parts): $6Hardware: Grommets,Screws, standoffs,etc: $2Cables to Scope: (Siglent recycled) $10Whatever else I forgot. Like LEDs.Kits are just the start. I can't wait to see what my Retro kit (boards only) runs or the VBA Curve Tracer (boards only) I will build come in at.But, there is value for money. This beats my 501A for convenience. Plus, I learned a lot from watching the video I forgot to post.He goes in depth into the theory of this unit.

author: watchmaker
author_rank: Unknown
timestamp: February 28, 2024, 04:19:09 pm
content: Thanks.I am too scatter brained. I need two ziffs for A/B and I need to have two highly visible configurations. I may even paint the front and rear sockets of the Ziff to help protect me against myself.As it is, I reversed the in/out on the amplifier board. I have to label and color code everything! But this is why I started this endeavor. It is helping me to avoid cognitive decline. I used to be one of the quickest kids in the room. Today I have to think for 5 seconds before I push a key on the TI89No whining, just dealing with who I am today.

author: Kosmic
author_rank: Super Contributor
timestamp: February 28, 2024, 04:25:09 pm
content: Quote from: watchmaker on February 28, 2024, 04:12:27 pmHaaa right maybe. That's why I don't keep track of how much I spend on my personal projects

author: watchmaker
author_rank: Unknown
timestamp: February 28, 2024, 04:33:36 pm
content: Quote from: dobsonr741 on February 28, 2024, 03:25:08 pmThanks for reminding me I forgot to post the YouTube video.If you mean my thread in the Repair subforum, I did not think anyone here would be interested in my trials and tribulations. SOme of those were caused by being dyslexic, a possible PSU problem and my starving the ICs by using 5.1V zeners rather that the required 6.2V zeners when I went for 4 1/2 watt to to 1 watt zeners.That YouTube is the best I came across on this damned kit. Forget about the mods, his discussion of the theory is terrific!

author: watchmaker
author_rank: Unknown
timestamp: February 29, 2024, 12:43:02 pm
content: In my excitement, I forgot to mention the person who supported my perseverance and confirmed that indeed the ckt as designed could be unstable.Thank you Jwillis.

author: watchmaker
author_rank: Unknown
timestamp: February 29, 2024, 01:31:57 pm
content: I just watched a video on how to overcome the limitation of this design regarding zeners and such that require the ability to vary the voltage by using the function generator and a pot. Brilliant. This design improves that shared by W2AEW.

author: mawyatt
author_rank: Super Contributor
timestamp: February 29, 2024, 01:57:25 pm
content: Here's a link to using a AWG and DSO for a crude curve tracer we did awhile back.https://www.eevblog.com/forum/testgear/fooln-around-with-dso-awg/msg4421209/#msg4421209Another link to a Curve Tracer concept for a more advanced Curve Tracer, we are way delinquent in finishing this project as other work took a precedent.https://www.eevblog.com/forum/projects/dso-awg-based-curve-tracer/Best

author: watchmaker
author_rank: Unknown
timestamp: February 29, 2024, 08:57:45 pm
content: Quote from: mawyatt on February 29, 2024, 01:57:25 pmThank you. Here is my expedient. My AFG has a max of 10 volts which means low voltage zeners only. But it should work for most of us amateurs.Over time I may add an amplifier.My Kikusui cannot even really pick up the knee. But the venerable Siglent 1104XE can. I took photos instead of screen shots to better show the setup.Also,as noteself and a breadcrumb, the hi current output is 13.3 X the low output. This makes little sense to me at the moment. I will change the 7.5K resistors to 10K for a useable 10X scale.