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  1. KrisBlueNZ

    Regarding water pump automation

    Your request is missing a lot of basic information. What is the pump voltage? AC or DC? How many amps or watts? How do you detect when there is water and when there isn't? What controls do you want? Just an automatic/manual switch? Anything else? What is your level of experience with...
  2. KrisBlueNZ

    28 inch Monitor won't power on anymore

    The electrolytic marked "1" seems to have stretched. You can see that the plastic wrapping doesn't come as far inwards on the top as it does on the rest. This is a sign that it has been getting hot. So you should definitely replace it. Remove it from the board and post (a) the full list of...
  3. KrisBlueNZ

    Is there any way to fix transistor voltage drop?

    You could try this simple circuit: Q1 is an NPN phototransistor which conducts through its collector-emitter path when exposed to light around the red and infra-red areas of the spectrum. Phototransistors are available with and without a base lead. If a base lead is present, RB should be...
  4. KrisBlueNZ

    Analysis of a high voltage direct current (HVDC) transmission system

    What do you actually want? Are you going to make an HVDC system yourself? Have you looked up HVDC transmission system on Wikipedia?
  5. KrisBlueNZ

    Change TV to receive UHF Channels

    It's unlikely you could modify the set. You would need a drop-in replacement tuner, or you would have to modify a tuner designed for a different set. The modifications could be mechanical, electrical, or both. Also, if the channel selection system doesn't have any way to choose between UHF and...
  6. KrisBlueNZ

    transistor beta and saturation current for switching

    I converted my post into a resource: https://www.electronicspoint.com/resources/saturation-in-transistors-bjts-why-and-how.28/
  7. KrisBlueNZ

    new 4 pole 3.5 mm jack plug, old cable

    That's very good advice from Gryd3 there. The four contacts in the plug are named as follows. Tip = headphone speaker, left side Ring 1 = headphone speaker, right side Ring 2 = microphone signal Sleeve = common aka 0V aka ground Use a multimeter on ohms range, or continuity test range, to...
  8. KrisBlueNZ

    Found ya!

    Hi Surge and welcome :-) I second Steve's comment about your post about your monitor. It's a pleasant change to see a good clear fault description, and to know that you've done your due Google diligence!
  9. KrisBlueNZ

    Looking for basic circuits on RGB LEDs

    Hi Trent and welcome to Electronics Point :) Here's a circuit using the "old school" methods that will give a colour cycling display on a single RGB LED. It requires a regulated 12V DC supply, and a common anode LED, and it uses three 555 timer ICs, four transistors, and various small...
  10. KrisBlueNZ

    Looking for a small, low rpm, higher torque motor. Help please?

    You need a stepper motor controller that can run the motor continuously at a steady speed, with some way of adjusting that speed. This would either be a stepper motor driver that includes that capability, or a stepper motor signal generator that can generate an appropriate continuous stream of...
  11. KrisBlueNZ

    Help with Fuse

    If you mean that the transformer's secondary is rated for 1A and you want to use a 3A fuse in series with it, there's a fair chance that if there's a fault downstream of the secondary (e.g. a shorted rectifier), the transformer won't be able to supply enough current to blow the fuse. So I would...
  12. KrisBlueNZ

    diodes 1n4003 and 1n4004

    The only significant difference between 1N4003 and 1N4004 is the PIV (peak inverse voltage) rating. This is the maximum voltage that the diode is guaranteed to withstand in the reverse direction, i.e. when the cathode is positive relative to the anode. The 1N4003 is rated for 200V and the 1N4004...
  13. KrisBlueNZ

    Need Some Help Figuring Out How to Use the PDSP2112

    It looks like it's designed to connect directly onto the address, data and control buses of a CPU. This is the internal bus structure used inside a microcontroller to communicate between the different parts - the processor core, the RAM, the ROM, the peripherals and anything else that can be...
  14. KrisBlueNZ

    Discharge path for buck-boost converter

    I don't understand your question. If you have no load on the capacitor at all, then it will only discharge due to its internal leakage. If you have a feedback circuit using a voltage divider across the capacitor, that will discharge the capacitor slowly, as Steve pointed out in post #3. If...
  15. KrisBlueNZ

    74LS193 counter issue - Please help

    And read the data sheet. Read it again. Read it until you understand it!
  16. KrisBlueNZ

    Is there any way to fix transistor voltage drop?

    No it isn't. Not "power" coming into the base, anyway. OK, that's fine. It won't take long for a little MOSFET to lose its smoke. It IS important for the MOSFET to switch cleanly, as Steve described. None of us is going to advise you how to make a circuit that we know won't work reliably!
  17. KrisBlueNZ

    74LS193 counter issue - Please help

    It looks like the CLR input is not connected to anything. With TTL and LS logic devices, unconnected inputs assume the high state. This will hold the counter reset. You need to tie the CLR input to 0V. Inputs should not be left unconnected. Any other inputs you're not using should be tied to...
  18. KrisBlueNZ

    Is there any way to fix transistor voltage drop?

    So the problem is that when light is present, the transistor turns on, but there's still some voltage between its collector and emitter, so the voltage across the load (in the collector circuit) isn't as much as it should be? An N-channel MOSFET will give you a very low ON voltage, but needs to...
  19. KrisBlueNZ

    A tip if the "upload a file" button does nothing

    Ah, I see. So it might be possible for a scripting language to get access to that attribute and change it. But it's not really the app's responsibility to work around a Windows bug is it? OK, I understand.
  20. KrisBlueNZ

    Can I use a resistor as a fuse?

    So, no conclusive result? Ah well, never mind.
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