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  1. kellys_eye

    Dry run protection for DC Solar Pump sourcing water from a borehole

    What 'perhaps' about it? Where was I specific about anything other than the PRINCIPLE involved? I doff my hat to your superior intellect. You have, recently, seemed to follow my posts simply to offer your own criticism of the advice I give. This is as small minded as you can get - but there...
  2. kellys_eye

    Dry run protection for DC Solar Pump sourcing water from a borehole

    so..... a 'relay' then. Stop being a pedantic ***.
  3. kellys_eye

    How to test a dual SIM device?

    Nearly all providers will have a service availability map for your location. Print out the maps from the two providers you are using then go to the areas where the signal strength overlap favours one or the other. Your phone will default to the strongest signal. Basic - but cheap.
  4. kellys_eye

    Possibly Zener diode identification

    Can you trace out the cathode end of it? Where does the supply come from, where does it go and any components 'inbetween'? You don't need to dig too deep to discover this but if the cathode end goes to the supply without going via a series resistor then it's a transient absorber (my guess)...
  5. kellys_eye

    Variable DC

    Motor speed control is usually achieved using a PWM (pulse width modulation) system - varying the DC will work but won't help when the motor is under load. Small motor control modules are readily available and very cheap...
  6. kellys_eye

    Possibly Zener diode identification

    Could be a transient absorber rather than a zener - particularly if it's connected to ground at one end.
  7. kellys_eye

    Simpson Model 260 7M Calibration

    Could be the test leads themselves or the mechanical adjustment for the pointer (but this would be apparent at 'no signal' so unlikely). In many test meters it is necessary to do a mental subtraction to counter the test meter lead resistance - even in 'accurate' digital meters.
  8. kellys_eye

    Dry run protection for DC Solar Pump sourcing water from a borehole

    What I described is, in it's very basic form, under-current detection - current flowing through the relay coil needing to be at a minimum level to ensure the contacts close. Wiring the relay in series with the motor means the relay dissipating the same energy as the motor - an obvious failing -...
  9. kellys_eye

    buggy board, bad tech and strange readout... heh heh

    No. QC wouldn't allow them out the factory. Didn't the thing work when you got it? Or whenever the original owner got it? Any failure during initial ownership would have been fixed under warranty so the thing HAS worked and probably worked well for years. The biggest problem is 'you' since...
  10. kellys_eye

    APEX JR. subwoofer amp blowing fuses, bad caps found

    If you can't do the ESR test then just purchase new capacitors - they're probably cheaper than buying a tester.....
  11. kellys_eye

    APEX JR. subwoofer amp blowing fuses, bad caps found

    You can't really test those regulators in the same way as transistors - that said, there are no measurements showing a short so they are probably ok. Worth investing in one of these...
  12. kellys_eye

    Drive a 1KW Marine Transducer

    Some old magazines had echo sounder schematics/designs that could easily be rehashed/updated.. Here's one I found in 'seconds'... http://n5dux.com/ham/files/pdf/Down-Under%20Depth%20Sounder.pdf
  13. kellys_eye

    Small amplifier project power requirements

    So a month is a 'lifetime'? Better start buying 'stuff' now as the delays are only going to get worse. Google 'headphone amplifier IC' and then Google for ready-made boards using that device. Something like this...
  14. kellys_eye

    Simpson Model 260 7M Calibration

    You need a 'standard' for whatever range it is you want to calibrate. Voltage standards are pretty common these days and even ordinary resistors at close tolerance are available off the shelf. Using these both will give you a standard current too.
  15. kellys_eye

    analogue perceptron

    There's a lot more than just that....... starting with your basic understanding of electronics. Clueless.
  16. kellys_eye

    analogue perceptron

    What? or, more specifically, W.T.F? (add-on) - are you talking about?
  17. kellys_eye

    Step up from 5v Powerbank

    Just use a 5V fan.
  18. kellys_eye

    Dry run protection for DC Solar Pump sourcing water from a borehole

    Possible solution - Wire a relay coil and contacts in series with the supply to the pump motor. The relay coil will only be energised if sufficient current is flowing in the motor (relay will have to be carefully chosen to find the right coil resistance). The relay contacts are temporarily...
  19. kellys_eye

    Home Based Income as an Electronics Hobbyist

    LOL - my post (now numbered #57) seems to lose its meaning since the offending post I was referring to has now been deleted!
  20. kellys_eye

    Dry run protection for DC Solar Pump sourcing water from a borehole

    Under-current detection? Use a switch-on timer to allow the pump to run up to speed and after this run-time limit, detect the running current and if it's too low remove the power/reset the system.
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