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  1. bertus

    Comedy Thread

    Thanks cmartinez AAC
  2. bertus

    Need help finding SMA jack | Noob

    Hello, This add shows long gold plated ones: https://www.ebay.com/itm/332726896289 Bertus
  3. bertus

    Forum Upgrade & Merging with Maker.pro

    Hello, Did you also get mails, you never asked for? I did not aks for mails from maker.pro. I already UNSUBSCIBED them. There should be an OPT-IN in stead of an OPT-OUT. Bertus
  4. bertus

    Forum Upgrade & Merging with Maker.pro

    Hello, The forum is part of the maker.pro site: Bertus
  5. bertus

    Freewheeling diode

    Hello, In some cases there are even Ultra Fast diodes needed. Of course the diode must witstand the voltage and current peaks. Bertus
  6. bertus

    Why amp is not stable while charging a 3s battery

    Hello: I think he means something like this: 3S battery A combination of 3 Lithium cells in one pack. Bertus
  7. bertus

    Making a BULK Floppy Eraser ???

    Hello, Perhaps these page might give you an idea: https://www.tapeheads.net/threads/how-to-make-tape-eraser.20920/ https://www.vintage-radio.net/forum/showthread.php?t=51270 Bertus
  8. bertus

    Making a BULK Floppy Eraser ???

    Hello, Perhaps an old Radio Shack eraser might work: https://www.ebay.com/itm/384237690365 For a more profesional solution have a look here: https://www.degausser.co.uk/degausser/94.htm Bertus
  9. bertus

    Making a BULK Floppy Eraser ???

    Hello, Would a degaussing coil work? https://www.newark.com/gc-electronics/9317/specialty-tool-degaussing-coil/dp/94F3457 From the datasheet: Keep away from any form of magnetic media. This unit will erase magnetic media. Bertus
  10. bertus

    I would like to repair my fridge-freezer. But what's wrong?

    Hello, The TS has not been seen from nov 9 2021. I will close this old thread. Bertus
  11. bertus

    4x AA batteries should be more powerful then 2x 300 mAh batteries, right?

    Hello, Did you notice the voltage on the white battery? There is stated 7.2 Volts, so there will be 6 cells in the white battery. The voltage of 4 AA cells will be 4.8 Volts, so to low. A higher mAh rating will give you no more power, but a longer working time. Bertus
  12. bertus

    Why amp is not stable while charging a 3s battery

    Hello, Is the amplifier working correct when not charging? Then there could be a problem with the charger. Bertus
  13. bertus

    Help needed with PSU

    Hello, The three diodes are for protection. When there is a voltage on the output (large capacitor), but the input is gone, the regulator may be damaged. Bertus
  14. bertus

    Help needed with PSU

    Hello, Did you look at the page I gave you? It uses PNP transistors to boost the LM317: That way, the regulator can be used in the "normal" way. You are using emittor followers, that will drop voltage to the output that will vary with the current. By changing R2 to the output of the emittor...
  15. bertus

    Help needed with PSU

    Hello, Have a look at this: Bertus
  16. bertus

    Help needed with PSU

    Hello, Is R9 supposed to be the current sensing resistor? Imagine 10 Amp through 47 Ohms. That shoud give a voltage of 10 X 47 = 470 Volt, wich will never happen. Also the power in the resistor will be huge: Bertus
  17. bertus

    Help needed with PSU

    Hello, You do not have feedback from the output of your supply. Also R4 and R5 will cause a large voltage drop. You will not get the wanted current with the given values of 22 Ohms for R4 and R5. Have a look at section 4 , figure 7 of the following page...
  18. bertus

    Why do they use a voltage divider in this instance?

    Hello, See the comments in the drawing: As the voltage drop accross the leds need to be 16 Volts. There is also some voltage needed for Re and accross the transistor. I estimate that the circuit will work from 18 Volts. Bertus
  19. bertus

    Freewheeling diode

    Hello, Have a look at the following pages: https://progeny.co.uk/back-emf-suppression/ https://www.westfloridacomponents.com/blog/what-is-back-emf-and-what-does-it-do/ Bertus
  20. bertus

    Views of individual thread counts

    Hello, You can see the information when hovering over the user name: Bertus
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