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  1. bertus

    And now something weird

    Take a couple of buckets and drum:
  2. bertus

    How do I test these transistors? (electronics noob here)

    Hello, @HellasTechn , They are NOT IGBT's as there is no mosfet as first transistor. They are special darlingtons with extra resistors and diodes build in: You can at least measure the resistors between S and E, they should be about 0.22 Ohms. Also you can measure de diode(s) between B and...
  3. bertus

    And now something weird

    This is what I call a weird motor cycle:
  4. bertus

    Need help to find output of board

    Hello, The PC817 chips are optocouplers. The BD140 is a PNP medium power transistor. Bertus
  5. bertus

    Book Reviews

    Hello, Here are some books from TI for download. Analog Engineer's Pocket Reference: https://www.ti.com/amplifier-circuit/op-amps/precision/support-training.html#pocketref And some cookbooks...
  6. bertus

    Use of a smartphone MEMS microphone for recording

    Hello, When it is coming from a phone, it could well be an OEM product. You will likely not find any data on the part. Bertus
  7. bertus

    Machine 5 position selector switch

    Hello, Why do you think they need to be replaced? Perhaps only the switch needs some cleaning. What is written on the other parts? I see one with 6800 and one with 4700 on it. Bertus
  8. bertus

    Error code for LTSpice

    Hello, @Harald Kapp , The 555 circuit is known as a hysteretic oscillator: https://www.allaboutcircuits.com/textbook/experiments/chpt-8/555-hysteretic-oscillator/ Using the formula on the given page, the frequency will be about 210 kHz. Bertus
  9. bertus

    Does Inductor and Capacitor get heated

    Hello, Like over voltage will heat up the capacitor, overcurrent will heat up the inductor due to saturation. Every part has its limitations. Bertus
  10. bertus

    Error code for LTSpice

    Hello, @Harald Kapp , Indeed, connecting the RST of the 555 to V2 will let the simulation run. The output seems to next to nothing: Bertus
  11. bertus

    Error code for LTSpice

    Hello, @Harald Kapp Yes, I get the same error. It seems to be related to one of the sources. It looks like the TS is trying to make a class D amplifier. Bertus
  12. bertus

    Error code for LTSpice

    Hello, @Harald Kapp , You must be missing some parts in your library. I get this in my LTSpice: Perhaps the user loaded the extra library from Bordodynov: http://bordodynov.ltwiki.org/ At AAC there is this thread...
  13. bertus

    Fluke 8846A defective due to overvoltage

    Hello, Unfortunately, the parts are not carrying any numbers on the picture of the given site: bertus
  14. bertus

    Fluke 8846A defective due to overvoltage

    Hello, Here I found a site with some more info: https://xdevs.com/fix/f8846a/ There are some clickable high resolution pictures. Bertus
  15. bertus

    Please help me build a truly silent mouse.

    Hello, Perhaps this review for quit mouses might help: https://www.quietresources.com/best-quiet-mouse/ There are more pages like this on that site for other things: https://www.quietresources.com/ Bertus
  16. bertus

    Fluke 8846A defective due to overvoltage

    Hello, It seems that the 8845 and 8846 share the same manual: http://www.jabse.com/L0ZsdWtlLzg4NDVhX3VtLnBkZg== There are some pictures of the 8845: http://www.jabse.com/L0ZsdWtlLzg4NDVBL3Bob3Rv Perhaps you can see something on those pictures. Bertus
  17. bertus

    And now something weird

    A metro derailed and is hanging on 10 meter:
  18. bertus

    COVID-19

    Spain - Man calmly plays piano amid chaotic anti-lockdown demonstrations
  19. bertus

    salt swimming pool chlorinator

    Hello, To have more an idea where you are talking about, I have here the manual. Bertus
  20. bertus

    SMPS analysis

    Hello, When D803 is shorted, the SPMS will not start, due to the fact that R816 and the coil 5 to 6 of the transformer will block the startup. Normaly R804 will be the starter resistor, wich has a rather high value, compared with R816 and the coil. The diode D803 will isolate the startup...
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