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  1. kellys_eye

    Need help to identify a MOSFET.

    Use the parametric search facilities on the usual supplier sites. That MOFET is rated at 600V and a measly 2A and ANY N-channel device in the isolated package that has values exceeding those noted will give you planty of options.
  2. kellys_eye

    Help with modifying Solar light

    Looks like a 'BigClive' schematic......
  3. kellys_eye

    Ultrasonic trans/rec transducer support hardware

    Shame you aren't UK-based. I could chuck a few items like those your way as I have a selection in my 'crap' box.....
  4. kellys_eye

    Know of a good reference book for electronics?

    You can under-run LEDs quite significantly before noticing a lack of brilliance from the LED - depends on the colour you're using - so the actual resistor dissipation could be significantly lower if you wanted. Of course, but these days things are very different and data is usually available...
  5. kellys_eye

    Ultrasonic trans/rec transducer support hardware

    https://www.esr.co.uk/shop/contents/en-uk/d2111978_Multiturn_Presets.html
  6. kellys_eye

    Ultrasonic trans/rec transducer support hardware

    10-turn presets are CHEAP.........
  7. kellys_eye

    Need help in converting a 12VDC 16.5A PSU to +-17.5VDC 2A PSU

    Perfectly possible. Remove the secondary windings (count the turns) from the SMPS transformer and determine the turns-per-volt. Rewind the appropriate number of turns for 35V but take a centre-tap from the new winding i.e. if it's 100 turns to get 35V then wind 50 turns, take a wire out and...
  8. kellys_eye

    Know of a good reference book for electronics?

    There are only limited amounts of data actually required to design most items so a 'book of everything' would not only be VAST but overkill for the most part. Over the decades I've downloaded all the datasheets I've ever needed and barely gone back to them since the day I did it - I have Gb of...
  9. kellys_eye

    LCD voltmeter for my power supply

    Those meters typically display the measured voltage AND take their power from the same source on the same pair of wires. Whilst they do work they WON'T work if the supply voltage drops below a minimum level (not sure what that is but 8-10V seems to come to mind)
  10. kellys_eye

    Block Cameras (CCTV)

    Not so sure about 'grateful' but, give me your home address and I'll send you a grapefruit.
  11. kellys_eye

    Amplifier SMPS died mid play

    That regulator uses external resistors to set the output voltage so you can trace which ones are connected to the 'adj' pin (and ground) and figure it out from the datasheet.
  12. kellys_eye

    Block Cameras (CCTV)

    I'm not concerned for any internal programming of the cameras - it's easy enough to find out what signals are what on the standard 7-way ribbon cable that runs from the camera module to the main circuit boards so 'direct' control of the module is possible to an extent. I'm more interested in...
  13. kellys_eye

    Amplifier SMPS died mid play

    Not sure about an alternative but we should be able to determine what voltage it is meant to be outputting and you could then apply that voltage from an alternative source to see if the rest of the circuitry is working (or to affect repairs/see if it's worth doing etc). To ensure your safety...
  14. kellys_eye

    Amplifier SMPS died mid play

    Before removing the suspect regulator, snip the lead where the leg bends (the 'knee') of the 'adj' terminal and check again. External parts may cause what looks like a short and can be misleading. Have you measured any DC at the 'out' pin of that regulator??? I hope it isn't 300V!!!!
  15. kellys_eye

    Linear Regulator Clarifications

    Quick and simple test would be to replace the PSU with one of higher output capability (say 2A or 3A). If it still doesn't work there are other problems than what you 'think' has happened.....
  16. kellys_eye

    Block Cameras (CCTV)

    I now have a growing collection of these CCTV block cameras as attached pic.... These are currently being used for experimentation including direct access control, replacing the sensor elements for high(er) resolution and total reworking for individual purposes. What I'd love to have is access...
  17. kellys_eye

    Linear Regulator Clarifications

    What is the load on the output? Are you using a suitable low-ESR capacitor on the output? Any stray capacitance? Is your PSU outputting enough current?
  18. kellys_eye

    When you can't find a box to mount your project in

    Hmmm. I got the impression that the steel stretched at those rounded corners but he didn't show what he did to shrink it.
  19. kellys_eye

    Power backup

    What you have seems to be a simple inverter. DC power input on the thick red (positive) and black (negative) wires. You MUST use a fuse (30A) in the red lead. Connect to the battery and switch on. You should, if the unit is working, get AC at the sockets. Make sure you reconnect that loose...
  20. kellys_eye

    I'm Back - Lost Soul From electronicspoint

    Kudos for your good sense ...
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