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  1. KrisBlueNZ

    Can this circuit works What changes I have to make to Drive 1w Leds on same circuit

    Thanks Adam. I'm already subscribed to the LTSpice groups.
  2. KrisBlueNZ

    Find Fault in my built amplifier

    He did, in post #18, but the numbers are barely readable.
  3. KrisBlueNZ

    Can this circuit works What changes I have to make to Drive 1w Leds on same circuit

    Yeah, I like it. I still haven't found a single bug. Thanks Harald :-) It doesn't run natively under Windows 7 - at least, not Win7 x64. It runs fine under DOSbox though. Yes, I use LTSpice for drawing schematics too, especially when I want to simulate them. But LTSpice is really short on...
  4. KrisBlueNZ

    I2V Converter Circuit

    The 1.2000V reference voltage needs to be pretty accurate. That's why I added all the zeros - so you wouldn't think it was just "about 1.2V". Zener diodes are not accurate enough. The Analog Devices ADR512 is suitable...
  5. KrisBlueNZ

    Timing Circuit? Counter?

    Sorry about the slow reply. Real life rudely intruded into my little online bubble :-) As Gryd3 said, the input voltage thresholds are set based on a 12V power supply voltage using RA~RD. Also the 9V6 threshold voltage affects the timing; it should be 80% of the supply voltage, whatever that...
  6. KrisBlueNZ

    machine language to assembly language

    No, those are ROM addresses; they are the addresses where the instruction opcodes and operands are stored. Code is stored in ROM. RAM is used for variables and stack. Are you asking a question or making a statement? That's right. Instruction opcodes and operand bytes are stored in ROM and the...
  7. KrisBlueNZ

    I2V Converter Circuit

    Yes, all resistor values are in ohms. You can change them as long as they're in that exact ratio - that is, 3000:3120:3250 (RB:RA:RF). The op-amp needs to be a low offset type. The 741 and the LF356 have too much input offset voltage to be accurate. That's why I specified an OP-07. Using power...
  8. KrisBlueNZ

    Can this circuit works What changes I have to make to Drive 1w Leds on same circuit

    I use an old MS-DOS package called OrCAD/SDT III from 1988. What do you think of them?
  9. KrisBlueNZ

    Gidday Everyone

    Hi Kevin and welcome to Electronics Point :-) Nice to see another New Zealander here. We have davenn who is an ex-Kiwi but he moved to the Dark Side (across the Tasman). I don't think we have any other Kiwi regulars here. Re your other thread, all I can suggest is Googling it to death.
  10. KrisBlueNZ

    Can this circuit works What changes I have to make to Drive 1w Leds on same circuit

    That circuit may work as drawn with some combinations of LEDs and battery voltages, but it's bad practice to drive LEDs without current limiting resistors. When your battery voltage starts to drop, the LEDs will become a lot dimmer quite quickly. The best way to drive high power LEDs is using...
  11. KrisBlueNZ

    Boom gate for car park

    As Adam said. We can help, but we need to know a lot more about the project. What does "monitoring" involve? Do you already have the PLC? Can you program the PLC to do your monitoring? Do you have the button? Do you have the barrier arm motor? What part do you need help with? This sounds like a...
  12. KrisBlueNZ

    Timing Circuit? Counter?

    OK, here's what I've come up with. This circuit must be powered from a clean, regulated 12V supply. It has an open collector output that goes low and latches low when the input voltage has remained between the two thresholds (1.3V and 0.7V) continuously for about 3.5 seconds. It is based...
  13. KrisBlueNZ

    Generate trapezoidal waveform for high power amplifier

    I've given your thread a meaningful title. Q3 is upside down in your schematic. Your output is shorted to ground. Your power supply polarity is wrong backwards. You should use driver transistors to provide high current base drive to your output transistors. If you want to avoid "crossover...
  14. KrisBlueNZ

    Help understanding solar lamp circuit

    No, that circuit is OK. The LED lights up each time Q3 turns OFF, due to the back EMF from L1. Here's a similar circuit I use for running a white LED from a AA or AAA cell for a miniature torch (flashlight). It does the same thing.
  15. KrisBlueNZ

    Help me finding capacitor

    10 µF is readily available in SMT provided you don't need a high voltage specification. Digi-Key's highest value is 680 µF at 16V rating. But ceramics are notoriously badly behaved. How about showing us the schematic diagram of where it will be used. We may be able to give useful advice then.
  16. KrisBlueNZ

    Please Help? Vacuum Tube TV

    A horizontal line is called frame collapse. Loss of drive to the vertical deflection coils in the yoke on the shoulder of the picture toob. In a toob set most problems are due to failed toobs. If you provide a make and model number, and we can find service information for it, we may be able to...
  17. KrisBlueNZ

    Need ideas for my blimp project

    Well, with two signals, you have two lots of frequency and two lots of amplitude to control, and both of those can be detected fairly easily and converted into voltages, so you would have four linear signals you could control independently. How many do you need? Two motor speed controls? Some...
  18. KrisBlueNZ

    reading a metal film resistor value

    Looks like brown black black brown something. Probably 1 kΩ. Have you measured it with a multimeter?
  19. KrisBlueNZ

    Help understanding solar lamp circuit

    Q1 and Q3 are a two-transistor relaxation oscillator. Q2 kills the oscillation when the solar panel voltage is high. It would help a lot if you rotated the whole circuit 180 degrees, so the negative (0V) rail is along the bottom and the battery is on the left. Can you redraw the circuit like...
  20. KrisBlueNZ

    Solar panels in series

    Assuming they have exactly the same characteristics in all respects: Supplies in series: voltages add together; current is the same Supplies in parallel: currents add together; voltage is the same.
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