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  1. KrisBlueNZ

    Computer Software to Simulate Circuits?

    Great info Harald! This should be in the Resources section.
  2. KrisBlueNZ

    Designing a Time Delayed Relay

    That's great! I'm glad you're interested in microcontrollers because they're a lot of fun. I've modified the circuit to use a microcontroller. You can see how many components it saves. Other changes I made in this version: Current detection in the 220VAC path is done with an ACS712ELC-20A-T...
  3. KrisBlueNZ

    Computer Software to Simulate Circuits?

    I agree it takes a while to get to grips with it. I only understand about 15~20% of its capabilities. It has lots of cool features but you have to go looking for them. The help is pretty brief, but good, and well worth reading from start to end. Undocumented LTSpice on the LTWiki...
  4. KrisBlueNZ

    Max232 Type Rs232 Chips - What Type Of Capacitors, MAX232 Charge pump capacitors

    No, you don't need to use polarised capacitors. It's just that the suggested capacitance values may be easier (and cheaper) to obtain in polarised types (e.g. tantalum, or aluminium electrolytic). As long as the capacitors you have are the right value, and your circuit won't be operating at...
  5. KrisBlueNZ

    frequency feed through MUX

    Yes, exactly. Yes. But the diodes could prevent the oscillator from working altogether. Yes, and yes. But you haven't shown us the complete circuit yet. Once you've done that, we can suggest ways to avoid that problem, if it's possible. While you're at it, explain what you want to ACHIEVE...
  6. KrisBlueNZ

    Designing a Time Delayed Relay

    I agree. I just discovered that the ACS712 requires 10 mA power supply current (13 mA maximum) which will increase the capacitance needed for C1, but that's not a big problem. The ACS712 has many advantages. That's definitely possible, especially if you hand-assemble the boards. I was assuming...
  7. KrisBlueNZ

    Toyota Rev Counter

    I wouldn't suspect electrolytic capacitors initially, as they tend to fail gradually, not become intermittent. But as Jagtech suggests, inspect the solder connections on the SMT components very carefully. In a high-vibration environment they can crack, and sometimes the cracks are very...
  8. KrisBlueNZ

    Bypass standby switch

    Hi James and welcome to Electronics Point :-) The simplest solution would be to short out the Standby button, but the humidifier may require a discrete button-press, and may ignore the button if it's forced ON. But you can easily test it to find out - just hold the button in, then switch on the...
  9. KrisBlueNZ

    Computer Software to Simulate Circuits?

    http://www.linear.com/designtools/software/#LTspice
  10. KrisBlueNZ

    Designing a Time Delayed Relay

    First, you don't NEED to do a PCB for this circuit for any technical or safety reason. You definitely need to keep the high-current, high-voltage paths away from the ICs but you can do that with stripboard by grinding off areas of copper. I think the decision depends on practical factors. The...
  11. KrisBlueNZ

    Wireless trigger for LEDs and buzzers

    Right. bytevalue is the local variable (local to that function) that will contain the value passed to the function as the function parameter. Right. Those assignments to port bits will be translated into bcf and bsf instructions. Those instructions read the port register, modify one bit, and...
  12. KrisBlueNZ

    Motion sensor lighting with a difference

    OK, good. OK. I'm not sure how you intend to distinguish between an object under the lamp, and the surface of the shelf under the lamp. If you want to return to the original behaviour, when movement of the child's hand will trigger the light to turn ON, then movement later will trigger it to...
  13. KrisBlueNZ

    My friend is considering disrupting the electronics components market in our city

    How many lines does he intend to stock? How much money does he have to buy stock with? How many cubic metres of space does he have for the stock? How long can he live for with no income? What is his advertising plan and budget?
  14. KrisBlueNZ

    C vs C++ with uControllers

    Well, an object-oriented approach affects how information is mapped to storage. Heavy reliance on indirect access is not efficient unless you have several pointer registers that can directly address reasonable areas of memory. For boolean data, forcing all of each object's attributes into a...
  15. KrisBlueNZ

    LED Rechargable Lamps

    They probably use a "capacitor fed" power supply where a capacitor is used as a current limiter. http://www.google.com/search?q=capacitor fed power supply&tbm=isch http://www.talkingelectronics.com/projects/200TrCcts/101-200TrCcts.html#3...
  16. KrisBlueNZ

    Wireless trigger for LEDs and buzzers

    It looks like you're using an array of ints to hold the bit values to be sent to the NRF. That's very inefficient; an int is 16 bits wide, and you would only be using one bit of each int. If the NRF always expects eight bits at a time (which it looks like it does), you should construct the data...
  17. KrisBlueNZ

    Repairing computer multimedia speakers

    I recommend you replace the whole cable. You can buy a length of twin screened audio cable and solder a plug onto the end, or you can buy a headphone extension lead with the plug already attached, cut the socket off the other end, and connect it into the speakers. Make sure you duplicate the...
  18. KrisBlueNZ

    C vs C++ with uControllers

    It depends on the microcontrollers you use. If you use AVRs or PICs, then C++ is not really appropriate, IMO. If you want to use an object oriented language on a small device, Java might be a better option, using exterrnal storage such as serial Flash. Assuming you don't have the need for...
  19. KrisBlueNZ

    Newbe needing help with simple limit switch project!

    Hi and welcome to Electronics Point :-) In case no one else answers this question, I can try to help. But I have no idea how a shrink wrapper works, and your description and nicely marked-up photos don't help me much. If no one else here can help, perhaps you could upload a video to YouTube...
  20. KrisBlueNZ

    Roland xp-50 keyboard problem

    Thanks for uploading that service information so quickly! If you're measuring AC voltages on the 12-pin plug coming from the transformer secondaries, with your black meter probe on the circuitry's 0V rail (the shield on the audio connectors, for example), the voltages you should measure are...
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