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  • netzener commented on netzener's instructable Switched Mode Dual Variable Power Supply4 months ago
    Switched Mode Dual Variable Power Supply

    Yes. That fuse will work as long as it fits on the PCB. The fuse voltage rating is the maximum voltage that a fuse can clear a fault against and still meet it's specified clearing time. The output of the converters is only about 20V and the input voltage from the switching supplies is only 24V. So your 32V fuse is still safe if something goes wrong with the DC-DC converters. You have a worst case safety margin of 133%.NetZener

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  • netzener commented on netzener's instructable Switched Mode Dual Variable Power Supply5 months ago
    Switched Mode Dual Variable Power Supply

    Maximum output current for this power supply project at full voltage (20V) is 2A so the DC output power per converter is 40W. DROK claims "up to" a 96% conversion efficiency which would leave 1.6W to be dissipated by the power inductor and switching transistors in the converter. However, assuming at least a 90% conversion efficiency for a worst-case input voltage/output-current, then about 4W would be dissipated. From my experiments with this power supply design, the converters are more efficient than 90% and the heatsinks get warm (43 DegC) at full power with the fan off after about 5 minutes of operation. With the fan running they are only about 5 DegC above ambient temperature. The heatsinks are sufficient for convection or forced-air cooling in a commercial grade envi...

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    Maximum output current for this power supply project at full voltage (20V) is 2A so the DC output power per converter is 40W. DROK claims "up to" a 96% conversion efficiency which would leave 1.6W to be dissipated by the power inductor and switching transistors in the converter. However, assuming at least a 90% conversion efficiency for a worst-case input voltage/output-current, then about 4W would be dissipated. From my experiments with this power supply design, the converters are more efficient than 90% and the heatsinks get warm (43 DegC) at full power with the fan off after about 5 minutes of operation. With the fan running they are only about 5 DegC above ambient temperature. The heatsinks are sufficient for convection or forced-air cooling in a commercial grade environment (0 DegC to 85 DegC). I wouldn't recommend enclosing them in a cabinet without some kind of ventilation which is why I recommended the case from IAASR or a home-built one just like it.NetZener

    Sure. As of June 5th, 2017 the US Amazon link is:https://www.amazon.com/gp/product/B00JKG57T4/ref=o...The product description is:DROK DC/DC Automatic Boost Buck Converter Module 60W Constant Voltage/Current Car Voltage Regulator DC5-32V to 1.25-20VThe Amazon ASIN number is:B00JKG57T4All of the above is subject to product profile changes made by DROK and Amazon so check in with me if you are having trouble finding the modules.NetZener

    Both converters I bought back in 2015 were well within the manufacturers published specifications which are:Input Voltage : 5-32VInput Current: 8A (MAX) peak 10A (6A long-term work)Quiescent Current: 4mAOutput voltage : 1.25-20V continuously adjustableOutput Current: 5A (MAX) (3A long-term work)Output Constant Current: 0.2-5AWorking temperature: -40 to +85 degreesOperating Frequency: 150KHzConversion efficiency: up to 96%The output voltage on the power supply I built varies between 1.2V and 20.1V and I can draw up to 2A continuous. From my experience, the manufacturers data sheet is accurate.All of the supplies in this project are overload and overtemp protected. Although the manufacturer states a peak output current of 5A, I would not recommend going there. The power supply project ...

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    Both converters I bought back in 2015 were well within the manufacturers published specifications which are:Input Voltage : 5-32VInput Current: 8A (MAX) peak 10A (6A long-term work)Quiescent Current: 4mAOutput voltage : 1.25-20V continuously adjustableOutput Current: 5A (MAX) (3A long-term work)Output Constant Current: 0.2-5AWorking temperature: -40 to +85 degreesOperating Frequency: 150KHzConversion efficiency: up to 96%The output voltage on the power supply I built varies between 1.2V and 20.1V and I can draw up to 2A continuous. From my experience, the manufacturers data sheet is accurate.All of the supplies in this project are overload and overtemp protected. Although the manufacturer states a peak output current of 5A, I would not recommend going there. The power supply project presented in this article is conservatively rated at 2A maximum continuous output current which is more than sufficient for most small to medium projects.NetZener

    I'm glad the article was helpful. Let me know if you were able to complete the modifications successfully. NetZener

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  • netzener commented on netzener's instructable Switched Mode Dual Variable Power Supply6 months ago
    Switched Mode Dual Variable Power Supply

    Most awesome! Excellent job. Very clean and professionally done. Looks like a commercial product and I bet you are very happy with it. There's nothing like looking at and using a device you built with your own hands. Enjoy! And congratulations. Thanks for sending the update!NetZener

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  • netzener commented on netzener's instructable Switched Mode Dual Variable Power Supply7 months ago
    Switched Mode Dual Variable Power Supply

    The first power supply you listed is the correct form factor. Part number B019OLU3E8.There are a bunch of distributors for the same power supply design so you will see a several different brands offering the same power supply at different prices. And those brands seem to come and go every year. That can make sourcing parts from Amazon very confusing sometimes.Let me know if you have any further questions or need assistance. I'm glad to help.NetZener

    For a fixed output power supply you could certainly leave the on-board multi-turn potentiometers in place and adjust them with a screw driver through a hole in the case. It would be a good idea to mount the DC-DC converters close to the hole in the case so that an errant screw driver doesn't accidentally short something on the converter.The only change I can think of from your description is that the 120V fan would need to be connected after the main power switch instead of to the 24V fixed supply as indicated in the project instructions. Other than that everything else can be wired as indicated.NetZener

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  • netzener commented on netzener's instructable Neon Goofy Lite7 months ago
    Neon Goofy Lite

    That's a great idea. It looks like the Hammond Transformer will just barely fit under the perfboard when screwed into the case specified for the project. If you are using a different case then you probably have more room. Send a picture when you're done. I'd love to see it!NetZener

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  • netzener commented on netzener's instructable Switched Mode Dual Variable Power Supply10 months ago
    Switched Mode Dual Variable Power Supply

    "Make do" is a good thing. Your character and ingenuity will shine.You can use the #24 solid core wire commonly found in CAT5e cables for the potentiometer wiring. Keep in mind that solid core wire fatigues easily when bent. It will break with just a few hard bends, especially at solder joints. So once you get it soldered to the DC-DC converters and potentiometer lugs, avoid moving the wire too much until you have secured the wiring with cable ties.NetZener

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  • netzener commented on netzener's instructable Switched Mode Dual Variable Power Supply10 months ago
    Switched Mode Dual Variable Power Supply

    If all you need is a dual variable power supply with a common ground between the outputs, then a single power supply can be used to power the DC-DC converters.The DC-DC converters are buck-boost type which use a common ground between the input and output terminals. It is not possible to use a single power supply and maintain return isolation at the DC-DC converter outputs. Electrical isolation between the DC-DC converter outputs allows the outputs to be used independently in circuits requiring different voltage and ground potentials, or stacked together for double the voltage output, or connected in a bi-polar configuration for use with op-amp or audio power amp circuits. I highly recommend dedicating a power supply to each DC-DC converter to make the dual variable power supply as us...

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    If all you need is a dual variable power supply with a common ground between the outputs, then a single power supply can be used to power the DC-DC converters.The DC-DC converters are buck-boost type which use a common ground between the input and output terminals. It is not possible to use a single power supply and maintain return isolation at the DC-DC converter outputs. Electrical isolation between the DC-DC converter outputs allows the outputs to be used independently in circuits requiring different voltage and ground potentials, or stacked together for double the voltage output, or connected in a bi-polar configuration for use with op-amp or audio power amp circuits. I highly recommend dedicating a power supply to each DC-DC converter to make the dual variable power supply as useful and flexible as possible.NetZener

    Many thanks for the kind comments. I'm glad you liked the article.The AC-DC power supplies described in the article automatically adjust for input frequency between 50Hz and 60Hz, and input AC voltage between 90V and 250V AC. No changes in the instructions are needed other than the AC power cord will need the 2-pin/3-pin grounded plug style used in your region. The power supply project uses a power entry module with an IEC C-14 socket commonly used in office equipment worldwide. So you will need an AC power cord with a C-13 plug on one end and the appropriate euro style grounded plug on the other end.If you build the power supply, be sure to send along a picture of your work. Instructables readers love that sort of thing, you know. Let me know if you have any questions are need a...

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    Many thanks for the kind comments. I'm glad you liked the article.The AC-DC power supplies described in the article automatically adjust for input frequency between 50Hz and 60Hz, and input AC voltage between 90V and 250V AC. No changes in the instructions are needed other than the AC power cord will need the 2-pin/3-pin grounded plug style used in your region. The power supply project uses a power entry module with an IEC C-14 socket commonly used in office equipment worldwide. So you will need an AC power cord with a C-13 plug on one end and the appropriate euro style grounded plug on the other end.If you build the power supply, be sure to send along a picture of your work. Instructables readers love that sort of thing, you know. Let me know if you have any questions are need assistance.NetZener

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  • netzener commented on netzener's instructable Neon Goofy Lite10 months ago
    Neon Goofy Lite

    This clearly places you in the "Freaking Awesome" category of electronics enthusiasts on Instructables.com. Not only did you build the project, but you reported back to the community your experience with the project, and you made it your own. That is the true spirit of this site. It is an honor to have played a small part with you, but you committed the time and you did the work! User rbusch also did this and I'm very happy about the feedback you both have made public on the site. Thank you!NetZener

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  • netzener commented on netzener's instructable Neon Goofy Lite10 months ago
    Neon Goofy Lite

    Many thanks for the encouraging comments. That photo of the neon lamp project with the 555 timer looks really cool! Radio Shack published some decent books during it's prime and the series written by Forrest Mims including the "Engineers Notebook", "Engineers Mini Notebook", and "Integrated Circuit Projects" were all excellent. If you need any assistance, or if you find any errors or omissions in the documentation please let me know. Thanks again!NetZener

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  • netzener's instructable One Tube AM Radio's weekly stats: 1 year ago
    • One Tube AM Radio
      7,583 views
      97 favorites
      17 comments
  • netzener commented on netzener's instructable One Tube AM Radio1 year ago
    One Tube AM Radio

    Many Thanks for the feedback. My desire is to be as clear as possible using a combination of words and illustrations so that anyone that wants to can successfully replicate the project. The current series I am writing for is intended to offer a moderate challenge using off-the-shelf parts and breadboard assembly techniques. Only some basic cutting and drilling is required. That way if someone is restless on a rainy weekend, they can do a project without having to set up the 3D printer, make a PCB, or write software. Those kinds of projects are fun, too. But they are a lot more complex and require equipment and materials the average builder is not likely to have in the shop. I work on extremely complex computer hardware and software designs during the day. Making smoke with a so...

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    Many Thanks for the feedback. My desire is to be as clear as possible using a combination of words and illustrations so that anyone that wants to can successfully replicate the project. The current series I am writing for is intended to offer a moderate challenge using off-the-shelf parts and breadboard assembly techniques. Only some basic cutting and drilling is required. That way if someone is restless on a rainy weekend, they can do a project without having to set up the 3D printer, make a PCB, or write software. Those kinds of projects are fun, too. But they are a lot more complex and require equipment and materials the average builder is not likely to have in the shop. I work on extremely complex computer hardware and software designs during the day. Making smoke with a soldering iron and publishing an analog design on Instructables is a nice break from all that for me.Any analog AM radio with a variable inductor and fixed capacitor for the tuning circuit could be adapted to the One Tube Radio project as long as it will fit on the breadboard and can be easily removed from the original PCB.Thanks again for the comment!NetZener

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  • netzener commented on netzener's instructable One Tube AM Radio1 year ago
    One Tube AM Radio

    Hello, rbusch! Nice to hear from you again!If you need any assistance, post a comment and I'll get right back to you. I was surprised as well about parts availability given how quickly technology moves through the product life-cycle. But then again, there weren't many parts in the original design so my redesign work was minimized. The only component I could not recover was the variable inductor which is the reason why I substituted it with a variable capacitor and the Miller-style antenna coil. The earphone is a ceramic piezo device instead of the Rochelle salt type. But analysis shows that the ceramic earphone is much more efficient even if its impedance is an order of magnitude lower at 1 kHz.When you complete the Bosch restoration, send some before/after pictures. I'd love to ...

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    Hello, rbusch! Nice to hear from you again!If you need any assistance, post a comment and I'll get right back to you. I was surprised as well about parts availability given how quickly technology moves through the product life-cycle. But then again, there weren't many parts in the original design so my redesign work was minimized. The only component I could not recover was the variable inductor which is the reason why I substituted it with a variable capacitor and the Miller-style antenna coil. The earphone is a ceramic piezo device instead of the Rochelle salt type. But analysis shows that the ceramic earphone is much more efficient even if its impedance is an order of magnitude lower at 1 kHz.When you complete the Bosch restoration, send some before/after pictures. I'd love to see them. Good luck!NetZener

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  • netzener commented on netzener's instructable One Tube AM Radio1 year ago
    One Tube AM Radio

    In fact I do remember the "Stripped Book" business that was the bane of the publishing industry in the 80's and 90's. Book sellers stripped the cover off their unsold paperback inventory and sent them back to the publisher as proof that the books were being sent out to be "pulped". However the folks handling the stripped books discovered that they were worth more in grey-market resale than as recycled paper. Some books had the warning message "If you purchased this book without a cover...it's an illegal book". But that didn't help much. It wasn't until the publishers established their own remaindering programs with companies like Texas Bookman in my area that unwanted books had a "second chance" market before being pulped.I'm glad we talked! ...

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    In fact I do remember the "Stripped Book" business that was the bane of the publishing industry in the 80's and 90's. Book sellers stripped the cover off their unsold paperback inventory and sent them back to the publisher as proof that the books were being sent out to be "pulped". However the folks handling the stripped books discovered that they were worth more in grey-market resale than as recycled paper. Some books had the warning message "If you purchased this book without a cover...it's an illegal book". But that didn't help much. It wasn't until the publishers established their own remaindering programs with companies like Texas Bookman in my area that unwanted books had a "second chance" market before being pulped.I'm glad we talked! Thanks for the kind words.NetZener

    Thanks, AnirudhA co-worker of mine in a good natured way once said, "even your mistakes are explained well and nicely illustrated". I said, "Hey! They are easier to correct that way!" I thought it was humorous.Thanks for the comment!NetZener

    Many thanks BeachsideHank. I'm so hungry right now I'm going to follow your Pizza instructable. Looks so good right now.NetZener

    Many thanks for the comment kode1303!I'm trying to improve my technical writing skills and Instructables is a good place to practice. It's a lot of work but it is so much fun.Thanks again for the comment!NetZener

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  • netzener commented on netzener's instructable Neon Goofy Lite1 year ago
    Neon Goofy Lite

    The original transformer was a center taped 1K ohm primary and a 100K ohm secondary. E-core laminated iron.NetZener

    Those were so cool. These days I use spray paint and sometimes a flat clear coat. Looks great but it's an extra step.NetZener

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