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  1. KrisBlueNZ

    SMPS Related

    1. The voltage on the drain of the main switching MOSFET has very fast edges and should be kept short to reduce (a) capacitive coupling, which will slow it down, and (b) emission of interference. 2. The source swings over a very wide voltage range - typically over 500V. A cutout is a convenient...
  2. KrisBlueNZ

    Help with RS485

    OK, you'll need to. The humidity sensor needs 4.0~5.8V. Also, the ADC0820 needs 5V ±5% (i.e. 4.75~5.25V) for best performance, though it will work from 4.5~5.5V. The ADC0820 is still available in DIP but it's a very old design. There are some alternatives that are also available in DIP, so it's...
  3. KrisBlueNZ

    DS1307 can not read and write time in arduino.

    Can you just post the URL of the data sheet please?
  4. KrisBlueNZ

    Small PCB From Power Supply Keeps Blowing 3A Fuse

    Right, the data sheet for the MIP0227SY is at http://pdf.datasheetcatalog.com/datasheet/panasonic/MIP0227SY.pdf. What's the brand and model of your multimeter? Can you post a photo of it? You can check the bridge rectifier and the MIP0227SY using a resistance (Ω) range. If the meter has manual...
  5. KrisBlueNZ

    Help with RS485

    The "parallel device" I'm suggesting is a one-wire slave device that provides parallel I/O that could be connected to an ADC. The part number is DS2408, data sheet at http://datasheets.maximintegrated.com/en/ds/DS2408.pdf This could be used along with a ADC0820 to trigger then read a 7-bit...
  6. KrisBlueNZ

    LED TV - power circuit damaged after lightning strike

    OK, I guess the FA8A00s are the next thing to try.
  7. KrisBlueNZ

    Comedy Thread

    Humorous auction page - currently viewable at http://www.trademe.co.nz/Browse/Listing.aspx?id=816759209 Captured for posterity (in several sections):
  8. KrisBlueNZ

    Help with RS485

    Oh. Well, in that case you need a way to convert the output voltage from the sensor into a value you can read on the one-wire bus. I can see two ways to do this. Either convert the sensor's output voltage to digital using a discrete ADC with parallel outputs (such as the ADC0820, which is still...
  9. KrisBlueNZ

    Help with RS485

    Hmm. That's a bit tricky. If you want to add custom devices to a one-wire bus, they will either need to operate through a generic one-wire parallel I/O device, or they will need a very small microcontroller such as a PIC. In either case, you need to find a way to power the sensor. That one...
  10. KrisBlueNZ

    Paint Sprayer Controller

    Rod, can you also post a photo of what's left of the device that blew up please? Edit: And at least one close-up photo looking directly down on the board and another looking directly at the copper side.
  11. KrisBlueNZ

    Hello Steve and All,

    Welcome Rod :-) I hope you enjoy it here at Electronics Point.
  12. KrisBlueNZ

    Paint Sprayer Controller

    Hi Rod and welcome to Electronics Point :-) We definitely need to see pictures. At least one of each side of the board. See https://www.electronicspoint.com/resources/how-to-take-photos-of-circuit-boards.6/ and https://www.electronicspoint.com/resources/photos-with-phones.27/
  13. KrisBlueNZ

    What cable/wiring to use with electret condensor mic

    Solder the braid to 0V at the circuit board (along with one of the inner conductors) but don't connect it at the microphone end.
  14. KrisBlueNZ

    DS1307 can not read and write time in arduino.

    Can you provide a link to the data sheet for the AP2306 devices that you're using to convert the I2C signals between 3.3V and 5V? I can't find a data sheet for it anywhere. If you can't post a link to it, upload it as an attachment to your post. If you don't have a data sheet for it, post a...
  15. KrisBlueNZ

    LED bags

    I don't think Isopropyl alcohol will do anything to hot melt glue. AFAIK you need to re-melt it.
  16. KrisBlueNZ

    What cable/wiring to use with electret condensor mic

    I don't know whether foil screening would be more or less effective than braiding. But definitely avoid the simple helical type of screening used with cheap cables. I suspect you'll have problems with electrical interference if you use the microphones near the engine. And not just in the...
  17. KrisBlueNZ

    Small PCB From Power Supply Keeps Blowing 3A Fuse

    Hi Sean and welcome to Electronics Point :-) That's a great video you posted there. I can make out a lot of detail. This is a switching power supply, and switching power supplies are well-known for failing in a way that blows the input fuse. The failure is often caused by a power surge, or by...
  18. KrisBlueNZ

    Aquarium canister water sensor fault

    Hi Neil and welcome to Electronics Point :-) There probably is a way to bypass that sensor, and you should definitely do that if you want to set your house on fire. Just make sure that your hack gets destroyed in the fire, otherwise your insurance company may refuse to pay out! Alternatively...
  19. KrisBlueNZ

    Strange transistor circuit

    Hi 35805512 and welcome to Electronics Point :-) It looks like the transistor's base-collector junction is being used as a diode. I suppose the designer could have done this to reduce the number of different components used in the design - SMT transistors aren't much more expensive than SMT...
  20. KrisBlueNZ

    Mini Nano ARM DSO201 Handheld Pocket Size Digital Storage Oscilloscope

    It looks like it's only single-channel, and that display is tiny and pretty low-resolution. Would he get better value for money if he bought a second hand analogue scope?
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