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  1. KrisBlueNZ

    Advice for starting a Project (Heat sensor switch)

    Hi there and welcome to Electronics Point :-) You certainly are organised. That's a pretty clear description of your situation! Have you considered buying a temperature controller? Also called a thermostat! Or do you have to do this the hard way? Are the fans mains-powered, or what? You can...
  2. KrisBlueNZ

    Rain Sensor Status

    Right. Well, you wouldn't see 40V across the rain sensor switch, whether it was closed or open. What you'll see across the switch depends on the characteristics of the input circuit in the irrigation controller - the part I marked "DETECTOR CCT". That's different from the voltage you'll see...
  3. KrisBlueNZ

    Old tractor ignition upgrade problem

    Sounds interesting. I'm looking forward to seeing the diagrams.
  4. KrisBlueNZ

    Resistance heater.

    I don't think the OP mentioned anything about batteries...
  5. KrisBlueNZ

    Help with TFT LCD

    Hmm. I think you're on your own with this one. You'll need to figure out the low-level protocol to be able to communicate with it, then you'll need to figure out the command set for the IC. The command set might be based on other similar controllers. The "CPNL" in all of the signals probably...
  6. KrisBlueNZ

    Another newbie

    You need software that lets you draw the diagram. Then you either export as image, print to an image capture driver, or take a screen shot. Most of the EDA packages at https://www.electronicspoint.com/resources/list-of-eda-packages.39/ will work. I like the schematics produced by diptrace...
  7. KrisBlueNZ

    Can I use a resistor as a fuse?

    That's interesting and odd. I'm interested to hear the response from Agilent/Keysight, if you get one!
  8. KrisBlueNZ

    Flickering white led on membrane switch

    Neale, you had posted this question six times on an unrelated thread. I have moved it to a new thread. What is the thing at the bottom left corner of your schematic? Is it a microcontroller that is using PWM to control the LED brightness? Do you have an oscilloscope? If so, look at the voltage...
  9. KrisBlueNZ

    Can I use a resistor as a fuse?

    How is it meaningful for a 0Ω resistor to have a 5% or 1% tolerance? Are you talking about 0Ω resistors or low-value fusible resistors? There is no reason for a 0Ω resistor to be wirewound. I've never dismantled one, but I imagine it's just a piece of wire with something attached around it...
  10. KrisBlueNZ

    Help with TFT LCD

    Also, take a photo of any markings, including company logos, on the module.
  11. KrisBlueNZ

    Rain Sensor Status

    Not sure. I didn't see exactly what you did.
  12. KrisBlueNZ

    Can I use a resistor as a fuse?

    Valid reasons I can think of for using a zero ohm link (THT or SMT) would be (a) to clarify the presence or absence of an option, (b) to take the place of an optional component whose position must be bypassed if it's not installed, (c) aesthetic reasons, (d) as a jumper wire with a body that can...
  13. KrisBlueNZ

    Rain Sensor Status

    Have a look at this diagram of your whole system. I've shown the AC adapter that supplies 28.5V AC RMS to the irrigation controller and your circuit, and the irrigation controller with its row of connectors, and the rain sensor switch (in the closed position), and parts of your circuit...
  14. KrisBlueNZ

    Another newbie

    Hi there and welcome to Electronics Point :-) Thanks for introducing yourself. Please, ask away!
  15. KrisBlueNZ

    Rain Sensor Status

    Yeah, I guess C3 would have seen about 40V across it. If it was only rated for 10V that would explain why it turned itself inside out! Electrolytics can be pretty dangerous. A former co-worker of mine had a medium-sized one explode just seconds after he had stopped examining the board up close...
  16. KrisBlueNZ

    12V - 350V 200mA converter for motorcycle CDI

    Hmm, that sounds strange. I'm not sure what to suggest. Did you leave the resistor across D8? If not, try it again and see whether it fixes this problem. Also, can you upload a clear photo of the component side of your PCB, and either a photo or a software-generated image of the copper side...
  17. KrisBlueNZ

    Rain Sensor Status

    OK, the valves and the circuit that detects the state of the rain sensor switch are presumably connected directly to the 24V AC power source. Outputs (to the solenoid valves) are via relays, and the input (from the rain sensor) is probably via an optocoupler. All my comments in post #74 apply...
  18. KrisBlueNZ

    Large array of 5mm LEDs (555 timer,LED flasher)

    Both of those circuits in post #3 will work. The N-channel MOSFET can be fed directly from the output (pin 3) of a 555 without a resistor, though a low-value resistor (e.g. 33Ω or so) is recommended. The second circuit uses the MOSFET in an arrangement called a current limiter. R4 isn't needed...
  19. KrisBlueNZ

    Rain Sensor Status

    And no DC voltage? What are the specifications for the control valves? Are they AC or DC? Not according to the data sheet. Just a switch contact.
  20. KrisBlueNZ

    Resistance heater.

    sureshot, yes you were right in post #6.
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