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  1. H

    Stop my house flooding

    It appears I stand corrected. Owing to the self-holding nature of 12V-R1, the annunciator functions as intended prior to the pump running as the water level rises, but not as the FLSW-L2 disengages at step 4 and the water level falls. I think I might be missing a trick, here, so any comments...
  2. H

    Hungry Dog

    The solution is remarkable simple, actually. I'm not going to blurt it out just yet.
  3. H

    Hungry Dog

    Given your efforts, isn't it about time Fido took a stand and threw his weight about a bit? As the old saying goes, a dog flattened by an opponent can get up again. A dog flattened by conformity stays down for good.
  4. H

    Stop my house flooding

    I have been known to overwork problems in the past. The idea of 12vDC SELV appealed to me given the proximity to water. I use a combination of Google Sketchup 8 for 3D modelling and Autodesk Autocad 2010 for 2D / line drawings and schematics. Sketchup is an excellent introduction into CAD. I...
  5. H

    Stop my house flooding

    I feel a bit silly now. Thanks for clarifying that. I'd appreciate that, and understand the inclusion of the TX and bridge arrangement to derive the 12Vdc wasn't really necessary. Thought it might be nice to guild the lily, so to speak, as I had a bit of time this evening. Thanks again Sintra...
  6. H

    Stop my house flooding

    Here is my attempt. Probably the last time I'll have a chance to sit down and look at these for a short while, but I'll try sit down next week at some stage and explain my reasoning. I'm not overly familiar with the term 'voltage free'. It strikes me as something of a misnomer, but rather than...
  7. H

    Maths - Resistors in series and parallel: Advanced

    This is all very welcome, appreciate the effort Mr. D.
  8. H

    Maths - Resistors in series and parallel: Advanced

    I've updated my original post with some of my workings. It might of some use, there, unless I've made a mistake along the way.
  9. H

    Hungry Dog

    It'll be the right hand microswitch that invariably interrupts the supply to the solenoid, so the solenoid must be fed via the N/C contact there. Therefore the common terminal on that right hand microswitch to be fed via the N/O contact on the left hand microswitch, and 230V supplying the common...
  10. H

    Maths - Resistors in series and parallel: Intermediate

    You solve Ohms Law with I as the subject, so I = V / R, or 13 / 3, which gives you the current through both of the resistors in series there. You can then solve for V as you have both I and R, so the voltage across the 30R resistor would be V = (13 / 3) x 30. The rest should fall into place...
  11. H

    Maths - Resistors in series and parallel: Intermediate

    That's it. You need both of those pieces of information to solve for the current through that series leg of the circuit.
  12. H

    Maths - Resistors in series and parallel: Intermediate

    That's the voltage measured or volt drop across the resistor.
  13. H

    Design me a circuit please

    Yes I see it now, thanks for the pointer, Marvo. With your comments, R1 does appear redundant. I should have reproduced the DOL a little more accurately, in hindsight. And I think that was what was bugging me. Thanks for all your efforts. Will come back early next week with a price. Haha.
  14. H

    Maths - Resistors in series and parallel: Advanced

    Thanks for the refresher, this is most welcome. Okay. I'll come back again when I'm at home and show my workings, but here is my attempt which I haven't confirmed myself. Just dropping it now off the cuff. All answers to two decimal places. Resistance total (Rt) = (1 / ((1 / (12 + 6)) + (1 /...
  15. H

    bit of calculations for the trainees

    Thanks for the share, Baker. I'm not going to attempt it just yet, but instead make another suggestion. For those confident enough to do so, perhaps they can also calculate the voltage drop across each resistor. What do you think, Baker?
  16. H

    Design me a circuit please

    Below is my first attempt along with a number of products that are referenced to it. I shall run up this materials list over the next day or so, as well as explain my circuit and reasoning in a bit more detail, even if it is proven to be incorrect. What struck me is that, in fact, the N/C...
  17. H

    Design me a circuit please

    Haha. Even down to the orientation of the relays... I'll try and upload my drawing later. Thanks again Marvo, that really makes it crystal clear.
  18. H

    Design me a circuit please

    Hey Marvo, I'm won't be at home until a little later; if my Teamviewer connection was active via my home desktop I'd retrieve my drawing and upload it now. It is reassuring to know that the arrangement you describe is essentially what I've drawn. Not that there won't be errors or suggestions, of...
  19. H

    Design me a circuit please

    Thanks for the link Marvo, you are quite right. I'v never had to spec a device like this, so cheers for the heads up.
  20. H

    Design me a circuit please

    My attempt at a circuit will go up later tonight. I do have a question, though, regarding the preset time for the floodlight to remain on. What came to mind when I read the brief was that that end of the circuit would need to be fed via a 555 timer, a watchdog timer or something similar and a...

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