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  1. KrisBlueNZ

    Dryer not spinning

    If the timer is the problem, I would definitely have a go at trying to fix it. It should be possible to open it up and see where the problem is. I expect!
  2. KrisBlueNZ

    Microcontrollers use a Crystal Why?

    The data sheet specifies the range of frequencies over which the device is guaranteed to operate. Here are some sections from the data sheet for the Microchip PIC12F629/675 which is available at http://www.microchip.com/mymicrochip/filehandler.aspx?ddocname=en011653. This diagram shows how...
  3. KrisBlueNZ

    Microcontrollers use a Crystal Why?

    All activity in a microcontroller needs to be controlled from a master clock source. This is provided by a crystal, or sometimes a separate oscillator module that contains a crystal, or sometimes a ceramic resonator, which is a cheaper and less accurate type of crystal. Often, a microcontroller...
  4. KrisBlueNZ

    Help programming an EEPROM (AT28C256)

    Yes, but you can't read the data back with that hardware. All you can do is verify it against the expected value, using the "8-bit comparator". You need to load the address into the address latch and drive -OE and -CE low, like you said, and assert the expected data value on port B. The LED will...
  5. KrisBlueNZ

    design buck converter with arduino controlling pwm

    For schematics I use a very old program called OrCAD/SDT III. It is an MS-DOS app and runs under DOSbox under Windows. It was commercial software and is not available for download. You need to control the duty cycle to achieve regulation. That means you need to monitor the output voltage...
  6. KrisBlueNZ

    Common anode or common cathode display?

    It would help if the markings on the display were readable! Find the part number on the side of the package, and look it up using Google or on http://www.digikey.com.
  7. KrisBlueNZ

    Help for hooking radio speaker to 3.5mm headphone jack

    The PAM8403 is an efficient stereo amplifier that can drive 4Ω loads with as much as 3W from a 5V power source. Available on a PCB very cheap on eBay...
  8. KrisBlueNZ

    change components for flip flop circuit higher

    The astable multivibrator is not a particularly appropriate circuit to use to drive an inductor. If you describe your whole project what you want to achieve, we can give much more specific advice.
  9. KrisBlueNZ

    Need help with Surround Stereo System? Please Help!

    I've just finished reading some reviews and marketing descriptions of the "Technical Pro" receiver-amplifiers. Very entertaining. Some creative writing there, for sure! Their "surround 1000W" tuner/amp is actually stereo, and claims only 75W per channel, and I suspect that's a lie too! But you...
  10. KrisBlueNZ

    Shadow signal

    Yes, I knew that. Yes I saw that but simulations often include placeholder circuits to simulate a separate part of the system, so the fact that an oscillator exists in the simulation doesn't necessary mean it's part of your overall project. No problem :-)
  11. KrisBlueNZ

    Analogue Proximity Sensor

    You don't need a microprocessor to go the ultrasonic route if you get clean reflections. You just need an oscillator to generate the tone bursts and reset a capacitor ramp, which you sample when the reflection is detected. You can be tricky with the detection amplitude to give it a crude AGC to...
  12. KrisBlueNZ

    Shadow signal

    LOL! I guess that's why it's so important to explain your requirements clearly. I assumed you had some uncontrollable signal that you wanted to echo. That's why I was trying to measure it with a capacitor. But it turns out you're generating the signal yourself so the solution is very simple.
  13. KrisBlueNZ

    Shadow signal

  14. KrisBlueNZ

    Shadow signal

    Yes.
  15. KrisBlueNZ

    Shadow signal

    So the duty cycle is always 20%? How about running the oscillator five times faster than what's required and clocking a 4017 set up to divide by 5. Then you will get a nice clean pulse for each 20% of the total cycle. You can pick off two adjacent ones for your main pulse and your shadow pulse.
  16. KrisBlueNZ

    Help programming an EEPROM (AT28C256)

    Right. -OC on the address latch can stay permanently grounded to keep the outputs enabled.
  17. KrisBlueNZ

    Designing a Time Delayed Relay

    https://www.youtube.com/watch?v=o7B6IHgV4Qk Yes, well, that's quite enough of that thank you very much!
  18. KrisBlueNZ

    Help programming an EEPROM (AT28C256)

    LOL Thanks :) There are several other people here who would have given a similar reply; I just got in first! Seems a bit silly to me. I think so. So you drive PC4 low, then assert the data on port A, and the LEDs change? There's a problem somewhere. As you said, when PC4 is low, the address...
  19. KrisBlueNZ

    Shadow signal

    Yes. The whole approach you've used isn't going to work. Switching power to the second oscillator ON and OFF won't synchronise it to the first one; in any case, how would the second oscillator track the frequency of the first oscillator? The whole idea isn't workable I'm afraid. The sensible...
  20. KrisBlueNZ

    Help programming an EEPROM (AT28C256)

    The three signals on PC7, PC6 and PC5 are -CE, -WE and -OE on the EEPROM, right? I don't think you need a separate bus for the inputs to the 8-bit comparator - you can drive it from PA7~0. I don't think you need the "8-bit switch" either - you can just disable the outputs on the 373 that...
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