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  1. KrisBlueNZ

    LED VU meter with transistors, dotted...

    You can use an op-amp-based inverting or non-inverting amplifier. Does the multimeter measure DC or AC? The difference is important. If it measures DC, you will need an envelope follower to convert your AC signal into a corresponding DC voltage. That DC voltage can then be amplified by an...
  2. KrisBlueNZ

    timer circuit stumper

    That's a strange circuit! It won't do anything like you want. Is this supposed to be some kind of watchdog circuit? While the switch is opening and closing at a rate of 2 Hz the LED stays ON, but when the switch gets stuck either closed or open, the LED turns OFF? That's the impression I get...
  3. KrisBlueNZ

    can clock to control a stepper motor ?

    A good way to generate an accurate frequency to control a stepper motor is with a crystal oscillator and a frequency divider. One rotation for a stepper motor requires a large number of step commands. The number depends on the stepper motor and is clearly stated in the data sheet for the...
  4. KrisBlueNZ

    Sign with 175 LEDs

    As Steve says, for a static display, all the connections and calculations are explained in that very helpful article. If you want an animated display, read on. For anything more complicated than a very basic sequence of illumination, you're going to need a micro of some kind to do the...
  5. KrisBlueNZ

    Send data with one wire protocol?

    Try Googling "implement 1-wire slave" (without the quotes). There's been plenty of discussion. It should not be too difficult, provided that you can guarantee a fairly low interrupt latency - that is, your interrupt handler needs to get control within a few microseconds of the 1-wire master...
  6. KrisBlueNZ

    mugatea

    I didn't necessarily intend for Mr. mugatea to see this post. If I had, I would have posted it on the original thread. It was my way to vent some frustration and provide a bit of humour. Perhaps you would consider removing the post on the original thread? At least we could let that sleeping...
  7. KrisBlueNZ

    Pickup Winder Build

    OK. First, you need to remove any jumpers from the 3x2 jumper block, to set it to plain ol' counter mode with no decimal point, as shown in the top left picture under "Function Selection". Then you need to provide a supply voltage, which is variously specified as "12-24V" and "5V or 9-12V"...
  8. KrisBlueNZ

    Simple amplifire

    I made a light emitting diode once. It was one of those germanium ones in the glass envelope, an OA91 probably. They have a nice little wire in there that glows if you pass too much current through them. Then it stops glowing. Oh well :-/
  9. KrisBlueNZ

    Amplifier power supply capacitor removal advice needed!

    In parallel means they're all connected "across each other". For example, put them all side-by-side and twist all the wires on one side together, then twist all the wires on the other side together. When you put several resistors of the same value in parallel, the resulting resistance is the...
  10. KrisBlueNZ

    Amplifier power supply capacitor removal advice needed!

    Yes, I would use 3W for safety. The originals might only be 2W but they have obviously been pretty hot. Yes, you need a tolerance of 5% or better. You could make them up from several smaller resistors in series or parallel. For example, you could replace each one with three 1.8k 1% 1W metal...
  11. KrisBlueNZ

    Quick LCD Question

    It looks like the interfaces are slightly different. The HD44780 uses the old Motorola bus interface, which has an E clock, R/W and a single-bit "address" (register select). This device uses separate RD and WR signals and doesn't have an E clock. If you're driving those signals using...
  12. KrisBlueNZ

    Mains powered SMPS.....Earthing?

    Any mains-powered appliance with exposed metal should either be double-insulated (does not apply to computer-type switching supplies) or should have the metalwork earthed to the mains supply. Every computer power supply you will see has its metal case connected to mains earth and this is the...
  13. KrisBlueNZ

    Simple amplifire

    LOL Laplace, nice work :-) To the OP: Click here.
  14. KrisBlueNZ

    mugatea

    I'm just coming here to vent, really. There's a new user called mugatea who has been posting quite a lot of nonsense on the thread titled "Can one CR2032 replace two CR2016 batteries?" (https://www.electronicspoint.com/can-one-cr2032-replace-two-cr2016-batteries-t253120.html#post1523230). I...
  15. KrisBlueNZ

    Can one CR2032 replace two CR2016 batteries?

    So far, you are failing quite spectacularly. We all know the point you were making, and you're right. Wrong. That paragraph shows that you have many misconceptions about the basic laws and behaviour of electric current. None of it is relevant, correct, or helpful. Again not true. You need...
  16. KrisBlueNZ

    Can one CR2032 replace two CR2016 batteries?

    If your remote is supposed to have two stacked CR2016es in it, it's designed to run from 6V. If you put a CR2032 in it, you will be running it from 3V. It may work but you are not using it as designed. I think you're being facetious. CocaCola was not saying that current is unimportant; simply...
  17. KrisBlueNZ

    AS Op Amps trouble...

    Input impedance for a standard op-amp is very high; it's practically infinite for FET-input op-amps. That's the impedance presented by the op-amp at its inverting and non-inverting inputs. The input impedance of an op-amp-based CIRCUIT may not be so high; it depends on the other components. The...
  18. KrisBlueNZ

    interfacing 3.6v flash memory to PIC microcontroller

    Yes, all agreed Steve. I should have explained those options in my post. I'm afraid I got distracted because I was thinking about the ADG3304 and trying to figure out what it was all about. That SerialFlash device will run at up to 3.6V. Its outputs (only MOSI in this case, called "SO") pull...
  19. KrisBlueNZ

    Transistor Mosfet pairs to drive LED cube layers

    Cool! Good luck :-)
  20. KrisBlueNZ

    Transistor Mosfet pairs to drive LED cube layers

    Right. And that involves transmitting 192 multi-bit brightness values to the cathode driver chips in 1.5 milliseconds. This is what I think you need to check for feasibility. Sure, and just as well! Something like that. On each multiplex interrupt, you would only update the cathode drivers...
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