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  1. KrisBlueNZ

    12VDC to 110VAC inverter needed

    So you bought an inverter via eBay and you got a unit without its main circuit board? As you can see, the circuitry required is a lot more than "a couple of transistors and capacitors". Why haven't you opened a dispute with eBay?
  2. KrisBlueNZ

    Trying to find out the name of a type of component.

    There are several components and circuits that fit your description. Why don't you tell us what you're trying to achieve. Show us a schematic of the parts you have, with the mystery component drawn as a box, and describe what you want the circuit to do.
  3. KrisBlueNZ

    MSP430 measure power consumption

    How are you measuring the current? Can you show that on the schematic? The way you are switching power to P5 won't work. An N-channel MOSFET requires its gate to be driven several volts positive relative to its source. You need to use a P-channel MOSFET with source and drain swapped. The MOSFET...
  4. KrisBlueNZ

    MSP430 measure power consumption

    Can you post a complete schematic as well?
  5. KrisBlueNZ

    Hello, Welcome! (Introduce yourself)

    What's the 'Big Yellow T"?
  6. KrisBlueNZ

    Stage Line 500W amp repair project

    What happened? Which components burned up?
  7. KrisBlueNZ

    The input given to Piezo Speaker is an analogue signal or Digital signal?

    OK. That is a standard mini loudspeaker, not a piezo. What do you mean, a "certain frequency sound (not the beep sound)"? If you feed it a signal at a fixed frequency, that will sound like a beep. That type of speaker has a low impedance (8Ω) and must be driven from a low-impedance source...
  8. KrisBlueNZ

    Need Help_New to Electronics

    Is the adapter's output AC or DC? It's probably DC but it's worth checking.
  9. KrisBlueNZ

    Interference in video switching circuitry

    OK, let's just worry about the screen with the white background, which is causing the problem. The trace looks fine, but it's not clear where the 0V DC level is. Can you do the following. 1. Disconnect the scope input and connect it to the earth clip so there is no input to the scope. 2...
  10. KrisBlueNZ

    a timing circuit

    1. What voltage do you measure across the 330Ω resistor? 2. What voltage do you measure across the 3.3 kΩ resistor with the phototransistor covered up? 3. What voltage do you measure across the 3.3 kΩ resistor with the LED pointing directly at the phototransistor?
  11. KrisBlueNZ

    Recommended place to buy remote controlled or IR relays

    Digi-Key and Mouser almost exclusively stock only well-known reputable brands. For relays these are Omron, Panasonic/NAIS, TE Connectivity, Potter & Brumfield and a few others. Digi-Key classify their relays into <2A and 2A+. If you want through-hole 2A+ relays, see...
  12. KrisBlueNZ

    transistor switching question

    Yes, that looks good!
  13. KrisBlueNZ

    Microcontroller controlled by pushbutton for LED flashlight

    No, we haven't abandoned that idea. Without a separate feed from the battery, the only way to get voltage to charge the reservoir is by turning the MOSFET OFF periodically. Assuming 10 µA current consumption (PIC in sleep state), and a maximum VDD voltage drop of 1V, with a 10 µF reservoir cap...
  14. KrisBlueNZ

    AC/DC Power Convert Questions

    The diode needs to be rated for at least as much current as the solenoid draws. If the solenoid draws less than 1A, a 1N4001~4007 as Trevor suggests will be fine. As for whether to add on or not: Without the diode, the inductive kickback will generate a high-voltage pulse which will cause...
  15. KrisBlueNZ

    Microcontroller controlled by pushbutton for LED flashlight

    It would take about 2 ms to charge 10 µF from 0V practically all the way to the battery voltage. The capacitor wouldn't ever fully discharge though, so 1 ms would be a closer estimate. If the PIC goes into sleep mode, its average current could be lower than 10 µA, using less than 50 µJ per...
  16. KrisBlueNZ

    Embedded device driver

    There's some pretty good documentation on the Keil site. Go to http://www.keil.com/c51/man/c51.htm and look at the User's Guides for Cx51, and the BL51 and LX51 linkers.
  17. KrisBlueNZ

    AC/DC Power Convert Questions

    If the solenoid is designed to be operated from the full 28V DC, then yes, I would say so. But I have no experience with the innards of pinball machines. I don't know why that wire would be labelled "Center Tap". Centre tap of what? I don't understand the question. The power supply needs to...
  18. KrisBlueNZ

    Microcontroller controlled by pushbutton for LED flashlight

    Just connecting a resistor across the LED driver won't cause a problem. It will just waste some power. It's only when you interrupt the power supply to the LED driver that the driver's operation will be affected. And then, it's not just the resistor value that will determine whether the micro in...
  19. KrisBlueNZ

    Embedded device driver

    If you've written some code, have a look at the assembly language output of the compiler. There should be an option that you can give on the command line of the compiler to tell it to create an assembly language output file. This file will show you how the compiler has translated each line of...
  20. KrisBlueNZ

    Hello, Welcome! (Introduce yourself)

    Hi John and welcome to Electronics Point :-) I hope you enjoy your experience here!
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