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  1. kellys_eye

    ips521 mosfet

    Well... not exactly. They are all devices that are called 'fully protected high side power mosfet switches'. The actual specifications of the device you currently have is in this document: http://pdf1.alldatasheet.com/datasheet-pdf/view/85007/IRF/IPS521.html The critical points to note are...
  2. kellys_eye

    Shaker Charger Guidance

    What voltage can you generate from the shaker charger now?
  3. kellys_eye

    ips521 mosfet

    Take your pick from the attached list: http://category.alldatasheet.com/index.jsp?Searchword=FULLY%20PROTECTED%20HIGH%20SIDE%20POWER%20MOSFET%20SWITCH
  4. kellys_eye

    help i.f transformer how to make one

    I think I've seen some articles on winding your own.... it's not easy but equally not impossible either. It IS, however, a lot of trouble! Here's one from a few years ago: http://www.rfcafe.com/references/radio-craft/if-coil-design-april-1932-radio-craft.htm What is your specific...
  5. kellys_eye

    Mini project, need some advice.

    You can get all the sensor AND display devices in an I2C 'flavour' these days so in theory only require TWO I/O lines....
  6. kellys_eye

    Ham Radio Projects

    you ain't kidding! LOL I'm all for the DIY aspect of ham radio - that's the only appeal for me - I've never owned a 'black box' rig of any shape or sort having always built from scratch. I did once purchase an FT200 but passed that on after only a few months as it was 'too easy'.... without...
  7. kellys_eye

    Old cctv camera repair

    Given the cameras are based on vidicon tube technology and the chances that the tube is defective/gone soft you could spend time looking around the circuitry (clamping/black level circuit) - which will require an oscilloscope as a bare minimum - but without experience of such things and lacking...
  8. kellys_eye

    Ham Radio Projects

    I've never seen the appeal of μwave comms - point-to-point, one-on-one, limited range (although I do appreciate the QRP aspect, getting the max from the min). I've made a few HF QRP items over the last couple of years - when I re-validated my licence after some 30+ years out of the hobby - and...
  9. kellys_eye

    Power-One power supply mod

    Great to hear - well done them. Adding to @hevans1944 comment, one of my most reliable and well-used power supplies was an LM317/LM337 pair delivering a variable 0-18V output that satisfied 99% of all my project requirements for years. I'd still be using it if I hadn't fallen for the...
  10. kellys_eye

    Light source transformer

    That is all the information you need. Got any pictures?
  11. kellys_eye

    Need assistance identifying this component

    Potentially a thermistor (PTC input surge protector) but I have to admit I haven't seen the likes before. Something of that age would need a full capacitor check - aged capacitors are a common problem in older equipment - but the fact that it's 'popped' (by the look of it) means there is...
  12. kellys_eye

    Relay differences

    If the membrane is rated at 30mA you may need two relays - a low current device connected to the membrane switch and a standard 30A (contact rating) relay to power the circuit you want. The alternative would be to use a switching transistor but that's an added complication. Either way you'll...
  13. kellys_eye

    Trigger Try Me button with motion sensor

    Most PIRs will show a detection pattern (range) in their specifications - beam width, beam height, range etc. The PIR will activate an internal alarm/light/whatever but you can also purchase SOME PIR detectors 'blank' which have relay contacts that are provided for the user to take power to...
  14. kellys_eye

    Coil can be replaced by Inductor for a bridge rectifier?

    Ahhh... I didn't see the coil connected to the free ends of the rectifier. Why not power them direct from DC in the first place? Not sure what 'pull' you require nor the operating voltage(s) but you can purchase pull solenoids cheaply anyway...
  15. kellys_eye

    Power-One power supply mod

    That's 3.33A per winding (secondary) - but only 18V. If they were wound for 28V then the current would fall to 2.1A A typical 240VA transformer will weigh around 3kg. Your transformer has a THIRD winding....???
  16. kellys_eye

    Mini project, need some advice.

    Consider an Arduino since those peripheral devices already have many sketches (libraries) written for them.
  17. kellys_eye

    Coil can be replaced by Inductor for a bridge rectifier?

    What's the reason for the bridge rectifier?
  18. kellys_eye

    150 VDC Power Supply T/S issues

    Given the age and the heat that the board looks to have suffered I'd be changing ALL the electrolytic capacitors!
  19. kellys_eye

    lcd sony tv

    Sounds like the LCD panel 'tape' (often with the drivers built straight onto the ribbon) has come away. Unlikely you'll be able to fix a fault like that.
  20. kellys_eye

    error code display from pulses circuit

    As already stated you need to detect the 'pause' between the first set of pulses and the second set. By applying the input pulse train to a retriggerable monostable you could use the monostable output to 'steer' the pulse train to the first or second counter stages. All this can be done in...
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