Another lucid explanation of a rather well thought out circuit. You are making me think again of electronic engineering that I have not done in many years. Thank you. I enjoy the re-learning!

Interesting!

@AccidentalScience

2 жыл бұрын

Thank you.

Just an idea... I would love to see your take on a DIY SMU. Source measure units are hard to come by and very expensive.... even second-hand or broken on eBay. I'm lucky enough to have one or two knocking around the lab only because I run across all types of test equipment from some of the manufacturers and lab type clients that I have. You know how it goes when they update or change directions......schools/colleges, government entities like the power companies... Small private manufacturers and labs... All those type places are famous for throwing away/giving / auctioning all kinds of instruments and equipment. Many times it can be had for free or for pennies on the dollar. That hopefully someone catches them before they literally just check it in the dumpster. I've seen $10,000 8.5 digit multimeters and all kinds of expensive gear that's only a few years old literally just get thrown down a garbage shoot. Matter of fact Marco reps here on KZread showed multiple videos where he was restoring an 8.5 digit meter on his channel... I think that was it ... or it might have been that big fluke calibrator... Whatever it was I don't remember but I know it was a $10,000 piece of equipment somebody had literally chunked into the dumpster before he ran across it. Like WTF!? STUFF THAT CAN BE SOLD ON EBAY FOR THOUSANDS JUST GETS THROWN AWAY!! I understand them not wanting to or being able to sell it or whatever... It's just more profitable to write it off. And in the case of governments where the equipment was purchased with taxpayer money... They're not really allowed to give it or sell it It's just easier to destroy it I guess. They see that is the only fair option for some reason. Government options used to be regular everywhere but they're getting fewer and rarer. but i have had friends and colleagues asked me about SMU's... Specifically because I specialize in the test equipment and metrology stuff... They thought maybe I would have a low-cost alternative for their workshop or lab. But that's WAYYYYY over my head. I might can troubleshoot and calibrate other designs .....but designing something like that from the ground-up is too far out there for my skill level and lack of brain cells There are few nice DIY examples on the net. DJ Erikson here on KZread has a very nice DIY version, Oh but he hasn't updated the videos on it in a while. and Marco reps was working on the OSMU (open-source measure unit)for years but has yet to publish anything. Which is super depressing because from what I saw of the design... Hundreds of hours had been poured into and it was going to be a real contender similar to his ultra precision references that he's working on the days. It would be a cool project and i would love to see your take on it

@AccidentalScience

Жыл бұрын

That's an ambitious project, and I already have a long list of things to do. Designing and testing an instrument with real well defined (and preferably good) performances takes a long chunk of time. For now I'm gonna to limit to a function generator and a power supply (AKA source of constant voltage/current), and possibly an additional current source/sink and voltage reference. All with some kind of voltage control. Also I have to complete the drivers for the motors that should drive the lathe... Anyway, thank you for the hint.

I have been developing sweep generator for oscilloscope horizontal deflection and I see that it is not easy task because on 10 or 20 MHz the signal will be extremely distorted. Maybe you know how it works on real devices? I tried to read the schematic of real oscilloscope which uses tunnel diodes but it's really difficult to understand

@AccidentalScience

Жыл бұрын

Basically for a triangle wave oscillator you need a capacitor a current source and a switch that discharges the capacitor once it has reached a given charge. What determines the speed is the switch: the fastest it is the cleaner the output signal is. A tunnel diode can be used for this purpose but honestly I have no experience with them. But I hope you get the idea: take care of that switch and a good circuit layout, that's the trick.

@Avrora707

Жыл бұрын

@@AccidentalScience thank you for your answer. I design DC power supply block with all needed voltages to cover all electronic blocks in oscilloscope. And than I am going to assemble vertical and horizontal amps and only after I will take sweep generator. So I will try to get more information about sweep generators and also about tunnel diodes. I think that diode uses its "negative resistance" part of charactristics. Or may be not🙂 But anyway thank you. Regards from Ukraine 🇺🇦

Seems overly complicated. A simple sawtooth generator can be made with three BJT transistors. A triangle generator can be made with a single comparator. The PNP current source can be replaced with a PNP current mirror and connected to an NPN current source to make the control voltage ground-referenced. To speed up the turning off of the transistor add a base-collector diode to turn the BJT into a schottky transistor. Regular 1N4148 works well enough. Other than that i don't have much to add.

@AccidentalScience

2 жыл бұрын

Thank you for commenting.