Search results

Search Forums New Posts
  1. KrisBlueNZ

    Attempting vintage receiver repair - Please Help!

    Yes, the part with the coloured dots is an inductor. See the "L201" marking on the PCB underneath? "L" means inductor. The parts in the other photo are almost certainly inductors too. Check the marking on the PCB. Their values are given in µH so "103" is 10,000 µH or 10 mH. The "J" is a...
  2. KrisBlueNZ

    How does a vaporizer actually work?

    "Dried herbs" eh... LOL :-) It's just a heater with temperature regulation. There will be one, or possibly two, temperature sensors, and the microcontroller will monitor the temperature and control the current to the heating element to keep the temperature constant at the ideal temperature for...
  3. KrisBlueNZ

    TDA2030 VS. LM383

    Well, both of them seem to be obsolete, which is never a good sign! There's also a problem with your supply voltage, if you use a single-ended output stage. If you assume that the output stage can swing fully to both rails (they can't), the maximum it can generate is 12V peak to peak. Divide...
  4. KrisBlueNZ

    Hello from TFahey!

    Hi Tom and welcome to Electronics Point :-) It's good to have you here. We get all sorts of questions, and I'm sure you'll be able to put your learning to good use here.
  5. KrisBlueNZ

    Attempting vintage receiver repair - Please Help!

    OK, thanks for the pics. I don't know what happened with the puff of smoke. Just connecting a multimeter to measure voltage between two points in a circuit won't cause any damage. You must have accidentally touched two different points with the positive probe and shorted them together. There's...
  6. KrisBlueNZ

    fetching and executing instruction?

    I/O ports are just like memory locations - they are addressed at specific addresses. The hardware detects a read or write access to the particular address, and either provides data onto the data bus (for a read), or latches data from the data bus (for a write). Some architectures map ports into...
  7. KrisBlueNZ

    How do I build a Metal Detector?

    No, the stupid questions are normally from genuine users :-) We had one guy who would copy a paragraph or two from someone else's post further back on a thread and repost it. And lately there have been quite a few users just posting spam as new threads. They usually get caught within 12 hours or so.
  8. KrisBlueNZ

    fetching and executing instruction?

    Yes, I guess so, but that's only a very broad description. What are you trying to achieve? Do you want to design your own CPU? If so, you should study the architectures of existing small processors such as the PIC, AVR, 8051, etc to learn exactly what they do.
  9. KrisBlueNZ

    How do I build a Metal Detector?

    I've heard that it does. I haven't seen any in my time here. The potential spammers have always been picked up well before they reach 10 posts.
  10. KrisBlueNZ

    Pic and JTAG Programmer

    I would contact the seller and ask for documentation and support software, or at least a web link. If they can't provide it, I would return it for a refund since it appears to be useless.
  11. KrisBlueNZ

    How do I build a Metal Detector?

    Yes, definitely. If you are reproducing a complete circuit design, you should always give the source. Personally, I would normally link to the original article instead of reposting the diagram. The diagram is only part of the picture; you need the accompanying text. Many schematic images...
  12. KrisBlueNZ

    Pic and JTAG Programmer

    Welcome to Electronics Point :-) Do you have any more information on the board? Manufacturer? Model number? Link to manufacturer's web page (not the eBay page)? Documentation that came with it?
  13. KrisBlueNZ

    How do I build a Metal Detector?

    That one was a special case. switychandra posted a whole section of text, verbatim, from an easily accessible source, with no attribution, implying that it was his own words. He's also a new user. This usually means that he's trying to reach the 10 post limit so he can spam users with lots of...
  14. KrisBlueNZ

    Hi from Scotland

    Hi Calgacus and welcome to the Electronics Point forums :-) Have you considered putting your location in your profile? It can be helpful at times - we can guess at your mains voltage and frequency, and we know what suppliers to recommend for parts. Hope to see you on the forums :-) Regards Kris
  15. KrisBlueNZ

    Split Rail Power Supply

    Yes Steve, you're right. The output impedance is too high unless an op-amp is used. I tried the circuit without L1, L2, C2 and C3, and got some pretty good numbers. The output impedance at the junction of R7 and R8 was about 0.001 ohms at 1 kHz, increasing to about 0.01 ohms at 10 kHz...
  16. KrisBlueNZ

    How do I build a Metal Detector?

    Posting other people's work without attribution is plagiarism and is bad netiquette. It is best to post the link to the article. In this case, it is http://www.instructables.com/id/bfo-metal-detector/
  17. KrisBlueNZ

    strong thermal glue for laptop DC power jack?

    Good! Do you have a replacement socket?
  18. KrisBlueNZ

    rs232 tx to XLR audio

    I don't think that will be very workable. RS-232 serial data can't reliably be fed through an AC-coupled signal path. Even if the data is continuous (no long periods of idle line), the DC average of the data will change constantly. Normally you would use a modem for this. There are several...
  19. KrisBlueNZ

    Help with Landline telephone

    It won't be economical to repair but sometimes people want to learn. Or reduce their e-waste. But to be honest, diagnosing the fault would be a lot of work for both of us, unless you can draw up a schematic from the board. Do you have any electronics experience? Do you know what all the...
  20. KrisBlueNZ

    Split Rail Power Supply

    Here's a schematic of the kind of thing I was thinking of. The input supply is shown on the left. I've specified an operating voltage range of 9~32V DC. D1 sets a roughly constant voltage across the Q5 circuit to minimise current variations with supply voltage. Q1~4 form a standard...
Top