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  1. KrisBlueNZ

    Changing strobe pattern?

    Yes, and Digi-Key's (and Mouser's) stock of THT is shrinking all the time :-( I wish they would distinguish leaded SMT packages, which aren't too hard to prototype with, from no-lead and BGA packages, which are. I have to go through the package field in the filter and deselect the unsuitable...
  2. KrisBlueNZ

    Can someone check this layout to see if its correct plz???

    Could you upload photos of your board and the test setup please. Have you added the decoupler? Also you could try isolating the 0V return of the capacitors from the path between the MCU and the LCD by making a track cut and bridge like this. No guarantee it will fix anything though.
  3. KrisBlueNZ

    Changing strobe pattern?

    The Microchip PIC is very popular, although I think the architecture is pretty horrible. But that doesn't really have much practical effect; the compiler takes care of the needed workarounds. It's available in a wide range of variants with different built-in peripherals. The 8-bit core is...
  4. KrisBlueNZ

    Changing strobe pattern?

    It's not "too messy" to implement with discrete logic; it's just "quite messy". But if you're interested in learning about microcontrollers, that's great!
  5. KrisBlueNZ

    Variable resistor question

    Trevor's calculations were written slightly wrong. When the rheostat is at maximum resistance, 35Ω, and is passing the maximum allowable current, 0.845A, the voltage across it will be: V = I × R = 0.845 × 35 = 29.575V The amount of power the rheostat will dissipate will be: P = V × I = 29.575...
  6. KrisBlueNZ

    Output of (voltage multiplier??) circuit

    I'm not sure what you're doing but I'm pretty sure it's wrong. You can't replace a diode with a capacitor. I've identified all the nodes on your circuit. The rail along the bottom is common to the input and the output, so I've called it the 0V rail; all other voltages and signals are measured...
  7. KrisBlueNZ

    Question about voltage divider

    OK. What is the input impedance of the Raspberry Pi's digital input? Is it just a direct connection to the CPU or is there a pulldown resistor, for example? Anyway, you understand how to do the calculations.
  8. KrisBlueNZ

    Question about voltage divider

    Yes, you're right. A voltage divider will only produce the designed output voltage if there is no load on it. The more it is loaded, the more the voltage will drop. If the load is resistive, you can calculate the effect by putting the load resistance in parallel with Z2. So we can't know VOUT...
  9. KrisBlueNZ

    How to deal with someone

    Hi vead. I never thought that you were rude. You can be difficult to deal with, but not rude or hurtful. We understand this. That is not your fault. And I'm sure you can learn. You just need to take it step by step. No one ever became a successful electronic designer or programmer just from...
  10. KrisBlueNZ

    Can someone check this layout to see if its correct plz???

    I've told you how to watch the crystal oscillator using your scope. Put a resistor between OSC2 and the scope probe. And don't try to probe OSC1. I doubt that you're overdriving the crystal. What is the crystal frequency? Are you using the same type (same manufacturer and part number) of...
  11. KrisBlueNZ

    LED Setup

    First let's assume you will be using PWM to control the brightness. That simplifies things a lot; when each LED is enabled by the control signal from the Arduino, you will be feeding a constant, known current into it. With common cathode LEDs, you will need to switch the positive supply to the...
  12. KrisBlueNZ

    Can someone check this layout to see if its correct plz???

    Well, your PCB could be improved, but I don't see anything wrong with it. But testing a crystal oscillator by connecting a scope to it can be a problem, especially if the scope has significant input capacitance, and especially if you connect it to the side of the crystal that connects to the...
  13. KrisBlueNZ

    Variable resistor question

    Yes, that's right, the current that flows will depend on the voltage across, and the resistance. That figure of 0.845A must be a maximum rating; you're not supposed to pass more than that amount of current through it, or you might damage it. That's a strange and very specific figure to specify...
  14. KrisBlueNZ

    Question for site manager

    Hi John and welcome to Electronics Point :-) We try pretty hard, and I think we mostly succeed, to be respectful and helpful to users who are less experienced. I see comments from time to time about how these forums are friendlier and more helpful than other similar forums. As has been said...
  15. KrisBlueNZ

    Laptop display connections etc

    Right. It probably also carries power to the TFT driver circuitry. That's the CCFL backlight power supply. It generates the high voltage for the cold cathode fluorescent light that backlights the display. The connector carries power and control signals (normally an ON/OFF signal and a...
  16. KrisBlueNZ

    help me to find datasheet for this mosfet-I have strucked

    Devices named AO... are made by Alpha & Omega, not Vishay. According to the schematic and parts list, that device is a P-channel MOSFET with a guaranteed RDSon of 19 mΩ at VGS = 4.5V. There are many devices that should be suitable...
  17. KrisBlueNZ

    Assistance with Transistor Theory

    I'm outta here!
  18. KrisBlueNZ

    Changing strobe pattern?

    Oh boy! And no additional features? That sounds like "famous last words"... There are a lot of factors. Assuming you're only building one, cost isn't a factor, and a discrete logic solution will be cheaper than buying a device programmer anyway. Of course you want it compact, but how compact? A...
  19. KrisBlueNZ

    power supply design help

    Hang on a minute. We've gone astray here. What kind of secondary does your transformer have? In your first post you said it was 12-0-12V AC. If that's the case, then you don't use a bridge rectifier with it. You use this circuit: Given that each half of the secondary produces 12V AC RMS, can...
  20. KrisBlueNZ

    1,2,3,4,5.. LEDs

    Hi there and welcome to Electronics Point :-) The CD4017 only activates one output at a time. You can use logic to combine outputs, but a simpler solution is a device called a shift register. The CD4015 is an example. It contains two 4-bit shift registers that can be cascaded to form an 8-bit...
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