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  1. KrisBlueNZ

    Alarm reset timer

    Yes, connecting the wiper to one of the end pins on the trimpot is fine. Yes, if you measure between the middle connections of the bridge rectifier, you are measuring across C2 and your multimeter will show a resistance that increases over a short time period then shows open circuit. You can...
  2. KrisBlueNZ

    Hadamard Gate

    Let me preface my answer by saying that I have no specific knowledge of Qwires, nor Hadamard gates. A NOT gate, also called an inverter, is an electrical circuit that accepts one logic-level signal (0 or 1) at its input, and produces one logic-level signal at its output which is the logical...
  3. KrisBlueNZ

    Crackpot Bingo Game

    To "Demonstrated to US Military" you could add "Originally developed by US Military" and "Discovered during Roswell investigations". Also, "Suppressed by the big power companies", confuses similar-sounding terms, applies concepts to situations they don't relate to, "Known for thousands of years...
  4. KrisBlueNZ

    Why I want my old world back!

    Perhaps she was a mechanic.
  5. KrisBlueNZ

    Hot Wire Cutter Power Supply

    I think it's best if duke37 advises you on this project. I'll answer the questions I can. I don't know what the item labelled SCHUMACHER is. Fuses normally only have two connections. I can only make out 12V and 12A in the marking, and Googling Schumacher 12V 12A -Michael shows that Schumacher...
  6. KrisBlueNZ

    Replace volume and input on circuit board

    Yes, you can do that. I added a note saying that at the end of my post, but you probably saw the first version of it. You should also connect the screen to the metal parts of the potentiometer - perhaps solder a wire to the washer that goes round the neck. This will also ground the front panel...
  7. KrisBlueNZ

    Replace volume and input on circuit board

    It looks like there's a Radio Shack in Franklin. They have a 50-foot roll of stereo screened cable which MAY be suitable - see http://www.radioshack.com/product/index.jsp?productId=2062643&znt_campaign=Category_CMS&znt_source=CAT&znt_medium=RSCOM&znt_content=CT2032227 Small quantities of audio...
  8. KrisBlueNZ

    Help on circuit

    Here's a circuit that implements the PWM LED control in the way Laplace suggested. There are quite a lot of components needed, I'm afraid. I tried to find an IC that would do most of the work, but I couldn't find anything, and I couldn't think of a clean and simple way to achieve your needs with...
  9. KrisBlueNZ

    What is the curent of a unity gain differential op amp?

    Another point: you should remove the marking "virtual ground" from the inverting input in your schematic. The inverting input of an op-amp is only a virtual ground if the non-inverting input is grounded. (Also the op-amp must be connected with negative feedback, and it must be operating within...
  10. KrisBlueNZ

    Replace volume and input on circuit board

    Yes, that's possible. You should probably use screened cable to avoid picking up hum and noise, and keep the cables short. Use the screens to make the ground connections - that is, the "sleeve" contact of the input connector, and the fully anticlockwise end terminal of the potentiometer...
  11. KrisBlueNZ

    Z80 programming help

    Hello and welcome to the Electronics Point forums :-) AFAIK the Z80 doesn't have any on-board RAM - unless you consider the registers to be RAM! Perhaps you're talking about some Z80-based device that has on-board RAM? If so, tell us the name of it, and look in its data sheet. If it's less than...
  12. KrisBlueNZ

    Hot Wire Cutter Power Supply

    The black, purple and yellow wires look like they connect to the primary of the transformer, which is wound with thinner wire than the secondary. I can't see the connections to the secondary. Assuming that the white thing mounted against the plate is a rectifier of some kind, there are two...
  13. KrisBlueNZ

    Voltage switch

    The way you have connected the sensor board is wrong. First, the sensor board's 0V rail needs to be connected to the 0V rail of the acquisition device. Second the board requires a power supply voltage of 6V +/- 0.1V to drive the hot wire inside the sensor, and the sensor draws about 200 mA from...
  14. KrisBlueNZ

    connection of a thermal sensor TC1047AVNBTR to the microcontroller MSP430F4618

    I can't understand your questions. The user guide has pages numbered 2~16; there is no page 18. The TC1047Axxxxx requires a power supply in the range 2.5~5.5V DC and draws 60 uA. You can power it from VREF if the VREF voltage and current specifications are suitable, otherwise you should power...
  15. KrisBlueNZ

    connection of a thermal sensor TC1047AVNBTR to the microcontroller MSP430F4618

    Actually no, I haven't been able to find any articles on that type of smoothing. Perhaps because it is very simple. The input has a corresponding "smoothed value" variable, which has several more bits of resolution than the raw value; these bits are called "remainder bits". New raw values...
  16. KrisBlueNZ

    Death of a yellow jacket

    Yeah, those photos look like what we call "German wasps" with the distinctive yellow and black stripy look. The name yellowjacket reminds me of yellowcoats, the unofficial name for the staff at English holiday camps like Butlins, and that so-called comedy show Hi-de-hi from the 1980s. And that...
  17. KrisBlueNZ

    Death of a yellow jacket

    Yeah it's a thing of beauty! No doubt it's irrational and cruel to take pleasure in the death of other living creatures, but I don't like wasps, and I just find the combination of the short zapping sound, the flash of light, and the visual of a small body falling from the unit, quite satisfying.
  18. KrisBlueNZ

    Help on circuit

    Laplace, yes I agree. That was the general idea I had too. The trouble is generating the control ramp with only 0.3V of headroom. I could use a resistor but then it won't be linear. I could reduce the positive peak voltage of the triangle wave... I see, you're suggesting generating the control...
  19. KrisBlueNZ

    Working with micro connectors

    You're right that Digikey have pictures missing. For connectors with that style, there are many manufacturers, and each has many product lines, and I have very little experience with them, sorry.
  20. KrisBlueNZ

    Help on circuit

    I would use PWM, with a low-VGS MOSFET as the switching device. This would remove the need to separate the LEDs, and provide a very low-loss path so no significant power would be lost at 100% brightness. A suitable MOSFET would be the Alpha & Omega AO4402...
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