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  1. KrisBlueNZ

    100VDC bus & arcing connectors?

    Why do you think disconnection could be problematic? I saw your other thread regarding DC voltage distribution for lighting applications. I don't personally know of any reason why it wouldn't work; I think the reason that it isn't often done relates to the fact that there's no standard for...
  2. KrisBlueNZ

    Phase detect compare

    The problem with using analogue methods is that you can't tell what part of the cycle each microswitch is "up to", because the signal from the microswitch only changes at two points in the cycle. A normal phase comparer circuit compares the phases of two sinewaves, which are continuous signals...
  3. KrisBlueNZ

    4 Channel Diversity Controller

    Good, Scott!
  4. KrisBlueNZ

    Phase detect compare

    Hi uvtal and welcome to the electronics point forums :-) That document is poorly written, as well as wrong in places. The relevant section is: This seems to be saying to me that the spinning anemometer has a magnet attached, and that this magnet operates two independent reed switches: the...
  5. KrisBlueNZ

    IC heating up!!

    What voltage is the VCC rail? The 40106 and 555 are only specified up to 15V and will overheat if VCC is more than that. It's best to use 12V for safety. Your input signal seems to be connected to the output of the 40106 gate; it needs to be connected to the input. It's not good practice to...
  6. KrisBlueNZ

    turntable hum and reduction of output

    Is the hum the same in both channels? Are both channels low in volume? Have you checked continuity of the phono cables from the plug tip through to the cartridge connection? And the earths as well? Is the sound normal, apart from being very quiet? For example, are the low frequencies missing...
  7. KrisBlueNZ

    I would appreciate any input

    There have been several threads on these forums about trans-cranial direct stimulation (TCDS). Search for TCDS, and TDCS (people often seem to misspell it).
  8. KrisBlueNZ

    need help with simple 3v to 34v transistor relay/switch

    If you're talking about using a timer interrupt, then I advise against it. Adding interrupts just complicates things, unless there's a real reason to use them. You may find that you need to use the USART received data interrupt, if the data rate is 115200 bps. That data rate corresponds to a...
  9. KrisBlueNZ

    need help with simple 3v to 34v transistor relay/switch

    Here's my suggested design for the USART receive function. I've realised that you probably don't need to match NO CARRIER. All you need to do is generate a burst of activity on the bell control outputs in response to every RING string. But I'll leave the code in there. static int UR_flags...
  10. KrisBlueNZ

    need help with simple 3v to 34v transistor relay/switch

    Yes, you have to structure the code so that independent tasks operate as separate threads. This doesn't mean that you need a full RTOS (real-time operating system), with pre-emptive multi-tasking, separate stacks, and so on. That kind of behaviour can be implemented without any of those things...
  11. KrisBlueNZ

    need help with simple 3v to 34v transistor relay/switch

    OK. Yes, interrupts are a good way to do what you want. In this application you can probably get away without them. Personally I would do the decoding in the function that receives the characters. You don't even need a buffer if you match the string as it's received. The interrupt handler would...
  12. KrisBlueNZ

    need help with simple 3v to 34v transistor relay/switch

    GSM modem idle current 25 mA? That's a reasonable figure. Yes, a 2000 mAh battery should give about 70 hours at that current. Have you confirmed that the GSM modem will work properly at 3.7V? The specification is very clear that its input range is 4.5~5.5V. If you need to add a boost...
  13. KrisBlueNZ

    Design question on microcontroller and TIP122

    Does the load, R2, need to connect to the negative rail? As BobK said, if you're using an NPN, it's more usual to connect the load between the collector and the positive supply, and ground the emitter. The way you've shown it uses the transistor as an emitter follower. In this configuration...
  14. KrisBlueNZ

    stepping down voltage twice

    Voltage regulators have a pretty low output impedance. Usually in the low ohms range or less. As long as both regulators are properly decoupled, I wouldn't expect problems.
  15. KrisBlueNZ

    Design question on microcontroller and TIP122

    It depends on how the two supplies are connected together. Are they completely independent? A schematic would explain a great deal. Show the MCU's power supply, the MCU, the other power supply, the load, and the position where you want to insert the semiconductor to control the load. I...
  16. KrisBlueNZ

    Help identifying chip

    http://www.maximintegrated.com/datasheet/index.mvp/id/4766 The device implements challenge-response authorisation using the SHA-1 secure hashing algorithm. You can download an abridged data sheet, but to get the full sheet you need to sign an NDA. So anyone who can supply a cracked replacement...
  17. KrisBlueNZ

    Simulator Simon

    Single electron devices? Do you mean Hydrogen?
  18. KrisBlueNZ

    Help with high current battery switching without putting the load through the switch

    You want to select one of the three batteries at a time and feed it to the output of the circuit? I think you should be able to do this with three of those big MOSFETs, IRLB3034, one for each battery. Connect the positive terminals of the three batteries together; this becomes the positive...
  19. KrisBlueNZ

    Can I have verification on this diagram?

    Hi mrblobby and welcome to the electronics point forums :-) Two of the pin numbers you've marked on the PCB are wrong. Have a good look at the data sheet: http://www.fairchildsemi.com/ds/FD/FDFME3N311ZT.pdf. On page 7 there's an illustration of how the pins are numbered. When you view the...
  20. KrisBlueNZ

    need help with simple 3v to 34v transistor relay/switch

    I'm not sure how much your code is doing, but 500 lines sounds like a lot for the functionality you've been talking about so far. You're probably doing things the long way; there are probably lots of techniques you can use to make your code shorter and tidier. Please feel free to post your code...
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