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  1. KrisBlueNZ

    Power supply circuitry not working

    Hmm, the plot thickens! You're right, if the adapter is plugged into the radio and the radio is turned ON, that should be a test of the adapter under load. I'm not sure you're right about which wires are carrying the power to the main board. Can you take a photo of both sides of the main board...
  2. KrisBlueNZ

    Tesla Coil Power Supply Understanding

    This project is extremely dangerous. This Greg who is suggesting that people make up circuits using microwave oven transformers should be prosecuted for reckless endangerment. No I'm not exaggerating. This thread is closed!
  3. KrisBlueNZ

    5 V to 1.7v (in SPI)

    Do you think it would help us answer if you told us the part number of the OLED and gave a link to the data sheet? How about if you posted a schematic of what you have so far?
  4. KrisBlueNZ

    Rain Sensor Status

    Oops! Well, at least you've solved the mystery!
  5. KrisBlueNZ

    General electronic questions

    Well, each pole pig will be supplying hundreds of houses, which are connected in parallel so their currents add together. But yes, if your house is drawing 100A at 120V, that will contribute about 2A to the current flowing in the 7 kV feeder. No! Think about the big picture here. Say your house...
  6. KrisBlueNZ

    Free samples from semiconductor Mfgs

    Yes, both. The usual reasons why companies give away free samples. The idea is that if you like their part, you will specify it for your high-quantity production runs, and they will recover their costs when they receive the first order for 56 tubes of 36 regulators each.
  7. KrisBlueNZ

    LED control box

    Hi there. Have you chosen the LEDs you're going to be using? Can you post the part number or a link to a data sheet? What supply voltage(s) do you have available? Do you want the strobe sequence to repeat? In other words, eight flashes on the first group of three LEDs, eight flashes on the...
  8. KrisBlueNZ

    Selecting PWM Freq for Speed DC Motor Control

    You shouldn't need much if any capacitance across the motor. If you want to convert your PWM to an actual DC voltage, use a design based on a buck switching regulator - that is, a series inductor and a catch diode, with some output capacitance. To reduce power dissipation in the MOSFET, make...
  9. KrisBlueNZ

    Nand Gate oscillator help

    The diode is probably OK. If you measure it out-of-circuit (removed from the circuit board) using the diode test range on your multimeter, with the black probe to the cathode (stripe end), you should get a reading of around 0.5~0.7V. 0.583V is fine. This voltage is called the "forward voltage"...
  10. KrisBlueNZ

    Wireless remote bell push to ring wired bell system

    So you want to put a wireless transmitter outside the gate, so visitors can push that button, and it will trigger a receiver that will activate the wired doorbell in your house? You can use any generic radio controlled switch for this. They are available fairly cheaply on eBay - search for...
  11. KrisBlueNZ

    Cleaning out a potentiometer

    Assuming that the pot is what's holding the board into the case, could you desolder the mounting tabs and connections of the pot and pull the board away, leaving the pot inside the case? Then you might be able to see how to get the pot out. Use desoldering braid or a solder sucker to make sure...
  12. KrisBlueNZ

    alba CX540XI/s BOOMBOX BLEW IC CHIP

    Nice work there groovejet! The UTC2206 looks like a drop-in replacement for the KT2206. Both of those data sheets are for equivalent devices; the Youwang one just has the IC drawn the opposite way round - possibly in a feeble attempt to avoid a law suit from the original manufacturer. But both...
  13. KrisBlueNZ

    Nand Gate oscillator help

    Right. If you have a diode between pin 11 and the rest of the circuit, then it will sort of work like an ON/OFF switch, with an undefined timeout. It will be slow to respond to the OFF contacts because the capacitor has to discharge through your finger resistance, and the timeout will be...
  14. KrisBlueNZ

    ATX PSU Power Toggle Circuit

    Thanks Adam. That was what I meant. Although photocopying isn't used much nowadays! But I've clarified the reason in my description.
  15. KrisBlueNZ

    How to set up a Beacon light to run from the mains

    Hi there and welcome to Electronics Point :) Yes, sure. Make sure the adapter is rated to supply enough current. The beacon light should have a current consumption figure marked on it. Get an adapter rated for at least 50% more than that amount of current. You may need an even gruntier adapter...
  16. KrisBlueNZ

    DC to DC conventer

    He would have to leave a bit of current available to run the cooling fans!
  17. KrisBlueNZ

    ATX PSU Power Toggle Circuit

    Here are my recommendations for how connected and unconnected wires should be shown on schematics for maximum clarity and minimum ambiguity. My reasoning: (a) is unacceptable because junctions should always have dots. (b) is unacceptable because it may be hard to distinguish from (m) if the...
  18. KrisBlueNZ

    DC to DC conventer

    What is the purpose of the load? Is it designed to test the motor's output power? So the alternator generates 12~18V DC? And you have 1Ω resistors? What is their power rating? How many of them do you have? Did you follow my calculations? Do you realise that to dissipate 2000W at 15V requires...
  19. KrisBlueNZ

    Best way to wind flyback core?

    If it's from a flyback transformer from a TV set, it's not intended to saturate. You can MAKE it saturate, but if it doesn't saturate sharply, you will probably waste a lot of energy during the period from when the core starts to saturate until the feedback voltage drops far enough for the...
  20. KrisBlueNZ

    DC to DC conventer

    So you want a load that will dissipate 2000W or more at 12~18V DC? I guess you'll need some big resistors, or perhaps a number of heater elements or jug elements in parallel. To dissipate 2000W at 15V you need a current flow of: I = P / V = 2000 / 15 = 133A. That's a hell of a lot of...
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