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  1. KrisBlueNZ

    Advise on industrial system

    This sounds like an interesting project! As Harald suggested, I would definitely use a high-ish DC voltage (e.g. 36 VDC) on the power wires, and convert down to 5V (or whatever) locally in each bar using a switching converter. This reduces the current being carried by the connectors and the...
  2. KrisBlueNZ

    Led sequencer/scanner

    That sounds really cool! Can you get any old circuit boards that might have a 4017 or a 555 or a ULN2003/2803? If you can't find the latter, you can use discrete transistors. You can also make the oscillator from discrete transistors. The sequencing logic can also be made with discretes in...
  3. KrisBlueNZ

    Current Limiting and Heat

    There ARE some cases when a lower resistance will run cooler. It depends on the circuit. For example, if you connect a power supply to a light bulb and insert a low-value resistor in series, a lower resistor will run cooler. This is because the resistor value doesn't affect the current much...
  4. KrisBlueNZ

    How to alternate 2 flip flops with 2 clocks?

    Yes, I mean solid state. Check out the CD4053.
  5. KrisBlueNZ

    Current Limiting and Heat

    Ignoring differences in heat dissipation efficiency, the temperature of the series resistor (above ambient) is proportional to the power it dissipates, which is the product of the voltage across it and the current through it. In your case with the tiny resistor that doesn't get hot, most likely...
  6. KrisBlueNZ

    How to alternate 2 flip flops with 2 clocks?

    I assume you mean an electrical switch such as a 4053. Yes, the output of the flip-flop can drive a CMOS bilateral switch device. There are other analogue switch devices available if you need special features (e.g. voltages outside the power supply rails); look on Digikey or Mouser.
  7. KrisBlueNZ

    Led sequencer/scanner

    I agree with KJ6EAD, you will need some kind of buffering, such as a ULN2003 or ULN2804 with extra transistors pr MOSFETs to make up the number you need. You don't need extra drivers to drive two displays though; just connect each pair of LEDs in series, connect the cathode of both strings to...
  8. KrisBlueNZ

    How to alternate 2 flip flops with 2 clocks?

    From your description, it seems that F1 and F2 outputs are always the opposite of each other. Therefore you only need one flip-flop. I would use a SR flip-flop, and convert rising edges on CLK1 and CLK2 to very short pulses to set and reset the flip-flop. CLK2 can be given priority over...
  9. KrisBlueNZ

    Current Limiting and Heat

    Yes, series resistors do waste energy. You can calculate how much energy using the Power law: P = V I, where V is the voltage ACROSS the series resistor, and I is the current through it (which is equal to the LED current). Using a larger resistor doesn't change the amount of energy wasted; it...
  10. KrisBlueNZ

    Design Project - Circuit Help!

    What are the characteristics of the handlebar heater elements? I'm going to assume they are resistive - made from resistive wire or something equivalent. If it's a Peltier heater, this answer doesn't apply. If the heaters are resistive, then the current they draw will be roughly proportional to...
  11. KrisBlueNZ

    Need help with strobe circuit

    You don't need a flash one for most stuff. That's good! If you have an enquiring mind, you can't really fail to learn. Yes, that's true. For example the 555-based oscillator is a bit like a library function that you would call. It's well-established and has a clear function. It's a bit...
  12. KrisBlueNZ

    Need help with strobe circuit

    I can't really see how a 556 would help in this application. A microcontroller-based design would be the simplest and most compact. CocaCola mentioned the 6-pin SOT-23 PIC microcontrollers (e.g. PIC10F322, see...
  13. KrisBlueNZ

    Need help with strobe circuit

    I was thinking that I would write the program as well, when I'm suggesting answers in the forum. In this case, for the model aircraft strobe, I would write the code and design the hardware. Then anyone who wants to build it would just need to install the development tools, buy a programmer and...
  14. KrisBlueNZ

    Need help with strobe circuit

    CocaCola, I take your comment as a compliment, thanks :-) I would also probably use a micro for any project more complicated than this, if I was designing for myself. In my previous job in embedded systems, I worked with AVR, 8051, MSP430 and several others. But it seems to me that avoiding the...
  15. KrisBlueNZ

    Need help with strobe circuit

    LOL thanks Chris :-)
  16. KrisBlueNZ

    Inductance and capacitance meter with AVR

    Does Proteus support ANY comparators? Any comparator that runs from 5V will work, for the simulation.
  17. KrisBlueNZ

    Inductance and capacitance meter with AVR

    OK... colour me wrong! To the OP. It seems that you should be able to simulate the project... if there's any reason to!
  18. KrisBlueNZ

    Inductance and capacitance meter with AVR

    Hmm, that's pretty cool. I wonder if it would simulate the LCD display so you can read the numbers on it...
  19. KrisBlueNZ

    Need help with strobe circuit

    This circuit runs from 5V. The positive/negative pulse circuit is based on another design I did for an electronics point user, to simulate a heartbeat. The 2N4403 drops about 0.2V so you can calculate the series resistor value from (Vsupply - 0.2 - Vled) / Iled. The pulse is about 10 ms long...
  20. KrisBlueNZ

    Inductance and capacitance meter with AVR

    Why do you want to simulate this design? This is a complete project that includes firmware. You don't need to simulate it; you just build it! You won't be able to do a useful simulation of it, unless you can simulate the hardware and the firmware, and the display, all at the same time. I don't...
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