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  1. kellys_eye

    Identifying a chip

    Where to buy? Somewhere reliable is all - Farnell is who I usually use.
  2. kellys_eye

    Step down converter and - lead

    Got any details for the converter? Sounds like it has 'isolation' but not all converters require you to keep this isolation.
  3. kellys_eye

    Measure current with strange output

    A cheap DC clamp ammeter and a cheap digital voltmeter.
  4. kellys_eye

    Emerson MW8779W doesn't heat but turns on!

    Check the h.t. fuse.
  5. kellys_eye

    Identifying a chip

    It's either an 74LS241 or LS244 device. Most likely the 244. Is it socketed? If not, fit one then get one of each device and try it - you will come to no harm by fitting the 'wrong one' (as the only difference is a chip select line and some inversion) but one of them WILL work. Since it's...
  6. kellys_eye

    1980 Soviet Radio Cassette amplifier problem.

    Have you checked the electrolytics to see what their ESR actually was? It would have been a shame to have removed them for no good reason (destroying the provenance of the radio). Regardless, I'm assuming you got all the polarities correct! Try giving R38 (preset) a little 'wiggle' as the...
  7. kellys_eye

    Arduino Sound generator wanted

    Ok, the XR2206 is a signal generator chip commonly used for generation of sine/square etc and fully controllable by voltage...
  8. kellys_eye

    Arduino Sound generator wanted

    What you're describing is basically an audio signal generator and there are Arduino-made boards all over eBay that do that; https://www.ebay.co.uk/itm/cool-Digital-DDS-Function-Signal-Generator-Module-Sine-Square-Sawtooth-Wave-W-DA/232581729303?epid=6008012238&hash=item3626f38c17:g:iHoAAOSwPIhaITLJ
  9. kellys_eye

    Cheap linear actuators

    I use a reduction geared motor to lift the hen coop door (timed, automatic) that I knocked-up a few years ago. I have a couple of motors left over (with, IIRC, 40:1, could be 60:1 reduction gearing) that I could send you FOC if you need one? The motors will run from 6V to 24V (nominally 12V)...
  10. kellys_eye

    Use an ignition coil to charge an electric fence.

    You don't switch the high voltage side - only the low voltage. Whilst a car ignition coil can easily be used for electric fence purposes a lot depends on the length of fence as it is the energy content of the pulse that makes it effective or not. Here's a link to a schematic that I posted for...
  11. kellys_eye

    Will this purchased adaptor be okay?

    It will be fine.
  12. kellys_eye

    PUPS Problems with Uninterruptible Power Supply

    We still need the power ratings - the actual figures, not generalities - as the battery to operate the PC (or UPS) will determine the final size of the unit. A typical powerful desktop PC may consume 300-500W at peak power, the monitor 25-75W giving a total of up to 600W and, when taking...
  13. kellys_eye

    PUPS Problems with Uninterruptible Power Supply

    How powerful is the desktop PC - what is its maximum power consumption when running the most processor-intensive software expected to be used? Will it be required to power the display too?
  14. kellys_eye

    Flushing my Toilet

    I asked that question of my Mother-in-law who had a bathroom refurbished and there, to my horror/surprise, was push-button toilet! One button for a long flush, one for a short, both with a lovely white pulsating LED lighting effect around the switch!
  15. kellys_eye

    N channel Fet v npn

    Switching 'on' resistance in MOSFETs can be considerably lower than any bjt device with a resultant low power dissipation in the device (less requirement for a heatsink). Switching speeds may be an issue as gate capacitance needs to be considered. These days there are MOSFETs for practically...
  16. kellys_eye

    Induction brazing?

    You need to heat the joint AND the brazing rod to make them flow together. Just heating the joint and 'prodding it' with a brazing rod won't work. Think soldering.... it's the same process and a soldered joint won't work without heating both parts.
  17. kellys_eye

    Help me understand a 12V SLA charging circuit.

    There are quite a few issues needed to be resolved in order to give the OP the answers required. Without the proper schematic you can neither give an accurate statement of how the circuit works and nor will any simulation software work correctly i.e. garbage in, garbage out. One area (the...
  18. kellys_eye

    Flushing my Toilet

    A solenoid would make a distinct 'clack' noise - not sure whether that would be acceptable or not. I'd go with a rotating disk (motor driven) with a rod connected on the end of an arm to give the 'pull' motion as it rotated through 360 degrees. Silent, smooth etc. Small electric motors with...
  19. kellys_eye

    The low quality busted headset sounds underwater effect

    Most likely you have distorted the speaker body and allowed the moving cone (often made of plastic) to touch the frame. These items, although cheaply made, are made to exacting clearances that don't tolerate manhandling.
  20. kellys_eye

    Help me understand a 12V SLA charging circuit.

    No, I can't. The Mods can - but I can't. Once a post has been made after mine, the contents of previous posts are locked and I can't change them. When YOU quote me, YOU can change the content - which you clearly have and used the letter 'O' instead of the number 0 - which makes you worse than...
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