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  1. KrisBlueNZ

    Dumb question re. simple inverter

    Here's another way to do it, using only one monostable. This means that you can adjust the duty cycle for both sides in just one place. It adds a CD4027 dual JK flip-flop (only one half is used) and a CD4081 quad AND gate (only two of the four gates are used). Use a decoupling capacitor on the...
  2. KrisBlueNZ

    Using 3 Channel Video Switcher Module with Arduino

    I guess that's a good reason to buy from real companies like sparkfun instead of anonymous eBay vendors. No doubt that module was cheap, but if you can't use it because there's no documentation, it has no value at all :-(
  3. KrisBlueNZ

    Curiosity: NPN Opto Coupler with no base

    You're right that the current into the collector pin and the current out of the emitter pin should be (will be) equal. Anything else would mean that the optoisolator is not properly isolated. So if you have a 1 kΩ collector resistor and a 1 kΩ emitter resistor, you should expect toget the same...
  4. KrisBlueNZ

    Behringer ub1832 fxpro potentiometer problem

    So let's get this clear. When the problem occurs, the signal stops completely, and none of the channel faders does anything, then if you slide some of the channel faders up and down a few times, the channels all come back. Is that right? Have you tried anything else apart from sliding the...
  5. KrisBlueNZ

    12V - 350V 200mA converter for motorcycle CDI

    OK, I won't be trying to suggest anything until you start using inductors with known characteristics instead of recycling bits from your junk box!
  6. KrisBlueNZ

    Stable floating power supply

    How about putting a regulator between your battery and your circuit? You didn't tell us what voltage you're working with, but regulators are available in a range of voltages, and adjustable versions. You may need to increase your battery voltage to provide headroom for the regulator. Avoid...
  7. KrisBlueNZ

    12V - 350V 200mA converter for motorcycle CDI

    What are your inductor characteristics? Can you post a schematic?
  8. KrisBlueNZ

    Behringer ub1832 fxpro potentiometer problem

    You can get the schematics for your mixer at http://elektrotanya.com/behringer_ub1832fx.pdf/download.html Can you describe the problem in more detail? By "most volume potentiometers", you mean the main faders? And what do you mean that they "don't work"? You mean there's no signal on those...
  9. KrisBlueNZ

    Zener Diode identification (color bands)

    Hi there and welcome to Electronics Point :-) Are you sure that component is a zener diode? It doesn't look like one internally, and its circuit reference appears to be SA101. Did you remove it (or at least one end of it) from the circuit when you measured it? If not, it's possible that other...
  10. KrisBlueNZ

    Alternative to IRF3205

    I don't understand. The MAX7219's outputs are multiplexed. It doesn't have 64 outputs. You have source and drain backwards. How are you going to drive 64 MOSFETs from the MAX7219? Why do you think the MOSFETs will have high heat dissipation? How much current does each LED strip draw?
  11. KrisBlueNZ

    What are the reasons for failure of diodes?

    Your image isn't showing up. Yes, a 1N4007 is fine. There's no need to use a fast diode because your switching frequency is low. (If it isn't, the relay won't be able to respond to it!) I've never heard of inductive kickback suppression diodes failing due to high dI/dT. But relay coils have...
  12. KrisBlueNZ

    Alternative to IRF3205

    Hi there and welcome to Electronics Point :-) The IRF3205 has a low RDS(on), and therefore, low power dissipation when ON, but it is not specified for a gate control voltage of 5V. The typical characteristics graph in the data sheet shows that it will typically have a reasonably low RDS(on) at...
  13. KrisBlueNZ

    Stage Line 500W amp repair project

    Hi again. Sorry for the delay. I try not to let my real life intrude into my online life but it happens occasionally :) I can't find Q21 and Q41 either. Where are they on the board? Can you take a photo? OK, I'm still not clear on all of these voltages. Here's a schematic marked up with...
  14. KrisBlueNZ

    Using 3 Channel Video Switcher Module with Arduino

    But you have a module there, do you? What are the markings on the IC?
  15. KrisBlueNZ

    Designing a Time Delayed Relay

    Yes, it was my gut feeling that some of the tracks could be thicker, but I'm not sure I can justify this. It used to be common to use wide tracks for all connections to bulky and heavy components, and connectors, to provide extra rigidity to resist copper ripping off the board if the board is...
  16. KrisBlueNZ

    LM386 Amplifier Module help

    LOL!
  17. KrisBlueNZ

    Hello all!

    Welcome to Electronics Point Sunim :-) I hope you enjoy your time here.
  18. KrisBlueNZ

    Using 3 Channel Video Switcher Module with Arduino

    What's the IC on there? And why have you connected an LED to it? It's a three-to-one video signal selector, right?
  19. KrisBlueNZ

    Designing a Time Delayed Relay

    Excellent John! That looks great!
  20. KrisBlueNZ

    Aquarium canister water sensor fault

    All I can suggest is that G is ground. As I said, I have no experience with these things. Sounds like shrtrnd does though.
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