tag:blogger.com,1999:blog-7057630065429233264.post6365029703902692146..comments2024-03-28T10:51:44.181+01:00Comments on Paul's DIY electronics blog: Tuning a 0..30V DC 0..3A PSU DIY kitpaulvhttp://www.blogger.com/profile/11421488581167758443noreply@blogger.comBlogger131125tag:blogger.com,1999:blog-7057630065429233264.post-41767305178544223882024-02-13T20:25:24.499+01:002024-02-13T20:25:24.499+01:00The schematic it's wrong, Paul isent understan...The schematic it's wrong, Paul isent understand noting only write and put pic.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-16325844201792080032024-01-28T08:21:19.935+01:002024-01-28T08:21:19.935+01:00hi paul!! very interesting observations you made o...hi paul!! very interesting observations you made on the power supply kit regarding o/p overshoot and undershoot..i bought the kit just few days back and after coming across your blog i felt hope less... regarding full 3amp capability and overshoots on power on... By the way can you suggest me a +/-24V dc fixed supply using LM317 ,Lm337 ,2n3055 and MJ2955 transistors with overload and short circuit protection scheme. Thanks very much. aerohttps://www.blogger.com/profile/17578803022929022503noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-55826359513275273152023-11-02T21:44:03.997+01:002023-11-02T21:44:03.997+01:00new links:
https://devincentiis.it/ADVe/DeVincenti...new links:<br />https://devincentiis.it/ADVe/DeVincentiisLinearPSU.pdf<br />firmware:<br />https://devincentiis.it/ADVe/ADVe231firmware.zip<br />video:<br />https://devincentiis.it/ADVe/ADVe231DigitalLinearPS-vid01.mp4 Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-55246368240623362192023-11-02T21:41:35.082+01:002023-11-02T21:41:35.082+01:00Hi everybody,
I improved by digitizing the chinese...Hi everybody,<br />I improved by digitizing the chinese circuit and replaced the final stage with that of the equally famous K7200.<br />Link to the schematic:<br />https://devincentiis.it/ADVe231/DeVincentiisLinearPSU.pdf<br />firmware:<br />https://devincentiis.it/ADVe231/ADVe231firmware.zip<br />video:<br />https://devincentiis.it/ADVe231/ADVe231DigitalLinearPS-vid01.mp4Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-84961374957496317112023-06-20T06:19:58.888+02:002023-06-20T06:19:58.888+02:00Interesting how that Early 70's circuit, and i...Interesting how that Early 70's circuit, and it's component values appear in a lot of recent circuits, How much is copied vs how much is worked out?.! Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-34593790246054329532023-04-22T14:56:41.607+02:002023-04-22T14:56:41.607+02:00Yes, I have also Czech edition :) Zdroj G400 - ELE...Yes, I have also Czech edition :) Zdroj G400 - ELEKTROinzert 6-7/96 http://paja-trb.cz/konstrukce/zdroj/zdroj_G400.pdf<br />from http://paja-trb.cz/konstrukce/zdroj.htmlWiValdiBBhttps://www.blogger.com/profile/15646605347329301584noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-50913121156862389722023-04-22T13:07:19.697+02:002023-04-22T13:07:19.697+02:00There are many designs using this concept. In the ...There are many designs using this concept. In the past projects were not so easily shared, because language barriers. So you can find it in various electronic magazines from the time, for instance a Greek design and I think also an eastern European has been mentioned, was it maybe Czech. The oldest one shown so far is the one in the 1978 Practical Electronics magazine.johanhnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-63608889301176967992023-04-22T11:27:23.367+02:002023-04-22T11:27:23.367+02:00OK, Thank You for an explanation, understand that ...OK, Thank You for an explanation, understand that . <br />My question were knocking my head as I thought as due to negative voltage differencies must be any min paramerter of each OpAmp type<br />Negative voltage closer to zero is better as we have higher max voltage to use as all voltage range goes up<br />Why then someone designed with 5V6 Zener diode?<br />Maybe specifically for 741 which were used in first design which I found<br />741 has Recommended Operating Conditions Supply voltage VCC– -5 to -15V<br />Many poples call this PSU as a Greek design, why? Where I can find original Greek design ?<br />The oldest design which I found is Practical Electronics 10/1978<br />https://worldradiohistory.com/UK/Practical-Electronics/70s/Practical-Electronics-1978-10.pdfWiValdiBBhttps://www.blogger.com/profile/15646605347329301584noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-49439237714958030932023-04-22T09:27:25.259+02:002023-04-22T09:27:25.259+02:00The negative voltage rail level is not so importan...The negative voltage rail level is not so important as long as it is at least -1V. It is there so you can adjust the output of the supply to zero Volt.paulvhttps://www.blogger.com/profile/11421488581167758443noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-71451337037143153812023-04-21T20:46:07.103+02:002023-04-21T20:46:07.103+02:00Paul, I have a simply for You question: Why design...Paul, I have a simply for You question: Why designed negatove power suppley for TL081 OpAmp is 5,6V and with TLE2141 1,3V ? My chinese kits has completely no marks on them so I dont know whta they completed, what I dont like<br />I must order other OpAmpsWiValdiBBhttps://www.blogger.com/profile/15646605347329301584noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-4054441178233203472023-04-19T22:48:53.092+02:002023-04-19T22:48:53.092+02:00Hi Paul, thanks for the answer. So one has the cho...Hi Paul, thanks for the answer. So one has the choice to use Vref=11.2V or go to lower lower voltages, that's good for people who want to feed the PWM directly from a controller.<br /><br />>There is little you can do wrong to make it worse<br />:-)) i read your opinion concerning this supply before and i saw your detailed investigation and development stages to build a better one.<br />I think it's a good, cheap project to learn something about current limiting and how it works. As mentioned above the schematic you provided is really great to support the understanding. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-33428907411699302612023-04-18T09:34:40.984+02:002023-04-18T09:34:40.984+02:00Thank you I will. Transformers with these qualitie...Thank you I will. Transformers with these qualities and different windings are hard to find and not cheap. When I need one, I will contact you.paulvhttps://www.blogger.com/profile/11421488581167758443noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-82091188492801285452023-04-18T07:47:14.157+02:002023-04-18T07:47:14.157+02:00But If in need then write me
I can give You few of...But If in need then write me<br />I can give You few of them for absolutely free.<br />I'm in Poland right now but I have sometimes Dutch guests here :)<br />Or I'm going to NL sometimes too, its so easy now, better roads, no brders, no passports needed, fuel could be some cheaper :) but no comparable to begin of 90s :)<br />Parameters are shown on attached photos<br />https://www.fotosik.pl/zdjecie/afc2576bff0a6d01<br />https://www.fotosik.pl/zdjecie/a4c208c57c39e69<br />I were working long time with electronic assmbly by R&R Electronics at Walwijk :) GroetjesWiValdiBBhttps://www.blogger.com/profile/15646605347329301584noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-27862535355117950112023-04-17T11:12:34.755+02:002023-04-17T11:12:34.755+02:00Hi Anonymous (;-)) Good work with the changes! I d...Hi Anonymous (;-)) Good work with the changes! I don't think the changes in the gain will adversely effect the supply stability. Unfortunately, I abondoned this supply years ago so I can't verify your changes. I'm afraid you're on your own, but since this is not a great design to start with, there is little you can do wrong to make it worse.paulvhttps://www.blogger.com/profile/11421488581167758443noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-11371372911158606792023-04-17T00:07:17.189+02:002023-04-17T00:07:17.189+02:00I like the way you arranged the schematic in revis...I like the way you arranged the schematic in revision 6. it became immediately clear for me how this supply works. in the original schematic and the other it was not so easy to follow.<br />I exchanged the potentiometers with a MCU controlled PWM. To keep the gains in the circuit and reference voltage and stability untouched, i used a level converter CD4504 to lift the 3.3V of the PWMs of the MCU to the level of the voltage reference. It works good, the given duty cyles and the measured real values on the output of the supply are strictly linear for both current and voltage. That was one of the aims i wanted to achieve.<br />Second aim was to get the output current reading against GND with an ADC on the same shunt (R7 in the original design) as the supply circuit itself does. The voltage drop across the shunt is negative (referred to the output minus as GND). So i put an extra OPamp (inverting) over the shunt, with its V+ on Vref (11.2V) and its V- on the negative voltage. In this way the measured current on this OPamps output is converted to a positive voltage which is easily readable by the ADC on the MCU.<br />So despite the already given linearity between setpoints and output one can also read the real values with the MCU and display it on a LCD, TFT or 7segment-LEDs.<br />After that work one can control all the necessary things with the MCU, and can also use rotary encoders and USB or RS232 controls. <br />One can further sweep/ramp voltage or current in a defined way and can even produce more complicated waveforms or sine curves in the low kHz range. with lots of power, but i haven't tried to use it as an audio amplifier for now :-)<br /><br />One question i have concerning the gain of the voltage amplifier, which is roughly given by R12/R11. I changed the zener diode on the reference opamp to 2.4V in a first attempt to bring down the control voltages on the potentiometers to values close to typical MCU supply values (3.3V - 5V). So the voltage chooseable on the V-poti-tap was not 10V anymore, but max. 3.3V. To still get 30V at the output, i reduced the R11 (27kOhm) to 6.8kOhm, which also works. So it's all fine with this, but: Is the stability of the supply now worse because of the increase in gain of the output stage? I haven't measured it, but in principle it maybe be oscillating earlier in special circumstances... <br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-61226876048896608312023-04-16T13:54:02.944+02:002023-04-16T13:54:02.944+02:00Many thanks for the compliments and the offer! I&#...Many thanks for the compliments and the offer! I'm just over an hour away from Putten by car, but when looking at the transformer, I have no need for one at the moment, but thanks for offering!paulvhttps://www.blogger.com/profile/11421488581167758443noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-52146481096403935852023-04-15T21:18:20.883+02:002023-04-15T21:18:20.883+02:00What kind of opamps You used and how You made -Vcc...What kind of opamps You used and how You made -Vcc? Finally how much it is ? Which circuit exactly You build a sis many variations, many modifications doneWiValdiBBhttps://www.blogger.com/profile/15646605347329301584noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-27831234055285903712023-04-15T20:56:24.844+02:002023-04-15T20:56:24.844+02:00Hi Paul, really appreciate Your work and time whic...Hi Paul, really appreciate Your work and time which You spent over this project, going to modify those as well<br />As You are in Holland, How far are You from 3881LJ Putten ?<br />I did some job as service with Bizerba, German made wieght scales, I have batch of trafos from dissasembled labelers and just want to give You some as a gift, if needed. Groetjes<br />https://www.fotosik.pl/zdjecie/afc2576bff0a6d01<br />https://www.fotosik.pl/zdjecie/a4c208c57c39e69WiValdiBBhttps://www.blogger.com/profile/15646605347329301584noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-64716161860776999242023-01-10T21:03:17.461+01:002023-01-10T21:03:17.461+01:00Yea that’s what I was thinking but I checked them ...Yea that’s what I was thinking but I checked them over and over, I was thinking maybe one of the components were bad or fake but on all 3 units though I don’t know about that lol, because they have all done the same thingAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-29203832541935515582023-01-10T10:19:09.359+01:002023-01-10T10:19:09.359+01:00This could very well be caused by an incorrect par...This could very well be caused by an incorrect part, as I have had myself. They simply put a wrong transistor type in the bag. Carefully check all parts.paulvhttps://www.blogger.com/profile/11421488581167758443noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-88820769772421825922023-01-10T06:25:39.534+01:002023-01-10T06:25:39.534+01:00Hello Paulv, I have yet to read your entire blog, ...Hello Paulv, I have yet to read your entire blog, but I have purchased 3 of these kits so far and all three of them will only reach 25V max and the CC led is on continuously. Also the units will not respond when I try to adjust the 100k ohm tuning pot. I am using a 25V AC transformer as my input and I have thoroughly checked to make sure I assembled them correctly. Any help will be greatly appreciated!!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-6210454428702343432022-08-05T10:14:56.777+02:002022-08-05T10:14:56.777+02:00Wandows,
Just above the diagram is information ab...Wandows, <br />Just above the diagram is information about the transformer I selected. There is also a lot of information on the original Blog about suitable transformers. The problem with this power supply design is that the raw voltage is also used to power the Opamps, and they have a limited rail maximum. This means that you can't get any lower but also not much higher than a 15-0-15 AC transformer.paulvhttps://www.blogger.com/profile/11421488581167758443noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-68064309843777314402022-08-05T02:04:07.203+02:002022-08-05T02:04:07.203+02:00According to the revision 6 diagram, what would be...According to the revision 6 diagram, what would be the maximum voltage of the transformer?Wandowshttps://www.blogger.com/profile/03587602137553509858noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-50006762873422188072022-03-19T10:13:13.229+01:002022-03-19T10:13:13.229+01:00I don't know anything about MC34071 Opamps. Yo...I don't know anything about MC34071 Opamps. You would have to dig in the datasheets yourself.paulvhttps://www.blogger.com/profile/11421488581167758443noreply@blogger.comtag:blogger.com,1999:blog-7057630065429233264.post-90318173598527911532022-03-19T07:19:23.583+01:002022-03-19T07:19:23.583+01:00do MC34071 opamps work in place of the 741 opamps?...do MC34071 opamps work in place of the 741 opamps?Anonymoushttps://www.blogger.com/profile/15428411559940590468noreply@blogger.com