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  1. KrisBlueNZ

    Designing a Time Delayed Relay

    The load current will be about 30 mA, so that's not a problem, but it will be dissipating about 600 mW, so a 78L05 will get pretty warm - especially a through-hole one. I think it would be better to use an SMT device so the board copper can act as a heatsink. The 78M05 is available in SMT and...
  2. KrisBlueNZ

    please help with my crossroad traffic light project...

    Now you've got pin 2 connected to 0V. It needs to connect to the same point as pin 6. You've also shorted the power supply out.
  3. KrisBlueNZ

    ANSI C IDE?

    (This post is in reply to post #8 below!) You definitely don't need to use a VM and Linux! If you want to practice C programming on Windows, making executables that run under Windows, you can use MS Visual C, or Pelles C that I recommended above, or lcc, or any of many options. I believe...
  4. KrisBlueNZ

    Hello

    Ah yes, job titles can be a bit silly. You can sit in a cubicle all day and harass people by phoning them when they're busy, and you'll be called a "client retention consultant" :-) But I think if you work with technology and you're responsible for making sure things work, you can fairly be...
  5. KrisBlueNZ

    Op-amp, changing LED colour!

    Q3002 is used as an adjustable current sink in that circuit. It's not just a switch. The clue is the resistor between the emitter and 0V. The resistors in series with the LEDs are not there for current limiting; they're just used to mitigate the effect of small variations in characteristics...
  6. KrisBlueNZ

    Hello

    What does being an "electronic security engineer" involve?
  7. KrisBlueNZ

    please help with my crossroad traffic light project...

    You haven't copied the 555 oscillator circuit properly. Pin 3 does not connect back to the timing components. The top resistor connects to VCC, not to pin 7. Pin 7 connects to the join between the two resistors. Pins 6 and 2 connect to the join between the bottom resistor and the capacitor...
  8. KrisBlueNZ

    Hello

    Hi Morgan and welcome to Electronics Point :-) It's great to have you on board.
  9. KrisBlueNZ

    please help with my crossroad traffic light project...

    The standard oscillator circuit using a 555 is shown in the data sheet, and in about a zillion places on the web: https://www.google.com/search?q=555+oscillator&tbm=isch Values of 100k, 100k and 10 µF are suitable for a starting point.
  10. KrisBlueNZ

    please help with my crossroad traffic light project...

    You don't need to connect pin 7 of the 555 to anything. Is the 555 oscillating? Does pin 3 change state periodically? If not, there's something wrong with the 555 oscillator. If it does, there's something wrong with the 4017. I can't see any errors in your diagram. Re R2 I was asking why you...
  11. KrisBlueNZ

    Repurpose grid-tie technology for local scalability?

    I have no experience with this but I imagine you might need one non-synchronising inverter to "lead the way". Otherwise you might have five separate inverters all playing follow-the-leader with no leader! That's really unacceptable. Have you contacted the seller? You should kick up a fuss. If...
  12. KrisBlueNZ

    LED Debugger to check sensor working

    Yes, there will be a simple way to do this, but I'm not sure I understand your description. So you have a signal from your IR sensor that goes into the input of the PIC. That signal is high when the sensor is detecting IR. And you want to drive an LED from that signal so it lights up when the...
  13. KrisBlueNZ

    please help with my crossroad traffic light project...

    Thanks for the new diagram, it's better. I've just noticed a mistake in the green/red connections. the green and red LEDs are swapped. You need the green and amber phases of one light to correspond with the red phase of the other light. Otherwise during each amber phase, one road will have the...
  14. KrisBlueNZ

    please help with my crossroad traffic light project...

    Hey, that's quite a clever circuit there D@rkL0rd! You're driving two sets of traffic lights and including an amber phase, and you've connected the LEDs in such a way that the red and amber phases for one light drive the green indicator for the other light. Nice! I can't see any reason why it...
  15. KrisBlueNZ

    Assistance with identifying this switch

    Hi there and welcome to Electronics Point :-) The general thing you want is a momentary pushbutton. Momentary means that it's spring-loaded and only stays down when there's force on it. Most likely SPST (single pole single throw - means there is one set of contacts) and normally open (means...
  16. KrisBlueNZ

    Help with Magnetek Model 6415 Power Converter

    Digikey is probably your best option then. Radio Shack don't carry many specialised components.
  17. KrisBlueNZ

    ANSI C IDE?

    Not sure if this will help you, but I found a really nice, compact, free C (not C++) development system for Windows. It includes an IDE and other development utilities, and can build command-line and GUI executables for 32-bit and 64-bit Windows. I converted an old MS-DOS app to Windows with it...
  18. KrisBlueNZ

    Help with Magnetek Model 6415 Power Converter

    OK here we go. Don't be freaked out by the amount of detail here. I intend to use this as a reference post that I can use to answer future similar questions. Here's my suggested circuit. Many of the component values aren't specified on the diagram because they depend on your requirements...
  19. KrisBlueNZ

    Help with Magnetek Model 6415 Power Converter

    According to the manual (also linked in the first post) it is not a float charger. There is a connection for a battery but it goes into a selector switch so the loads that are powered from the "converter" can be switched over to the battery when there is no mains power. Relevant quotes from the...
  20. KrisBlueNZ

    Basic LED help please!

    Right, it sounds like your resistor needs to be rated for a much higher power dissipation. Your LED requires 1A (that's a LOT for a LED, especially continuously!) and dissipates 2W, so yes, the voltage across the LED will be 2V. Voltages in series add together, so your resistor will drop the...
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