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  1. kellys_eye

    12 volt relay to start a 24 volt motor

    Why use two when one will do? The 24v relay isn't 'rare' so use the right part for the job - is my motto.
  2. kellys_eye

    Accuracy of digital multi-meters?

    Not really. Close tolerance resistors are not just matched by 'resistance' they are also matched to their temperature profile so simply using 'selected' resistors from ( say ) a bunch of 1%ers doesn't guarantee 0.05% accuracy.
  3. kellys_eye

    Solder Sucker

    Those simple solder suckers are fine for occasional use but I'd recommend you get a short length of silicon tubing to slip over the tip - saves the end on the sucker and gets you closer to the solder, making a much better job of sucking it off (giggidy) .
  4. kellys_eye

    Lcd screen controller board overheating?

  5. kellys_eye

    Breadboards are awesome!

    There are also some truly awful breadboards out there too. If you must buy/use one make sure it's good quality.
  6. kellys_eye

    Inductive sensor

    DC or AC?
  7. kellys_eye

    Accuracy of digital multi-meters?

    What value resistors are you using in the ladder? What are you using to switch the resistors? Is the switching device 'contact' resistance linear?
  8. kellys_eye

    PWM circuit

    The 2N3906 is rated for a collector current of 200mA (from memory) - is this sufficient for your motor. The motor would also need a protection (BEMF) diode across it. Without it you may have simply blown the transistor! Double check the transistor pin out too - those TO92 packages often have...
  9. kellys_eye

    AIC4100 Data Sheet

    Do you have a schematic of the device 'in use'? The worst thing anyone needs to read is 'customised' - this usually converts to a dead-end as far as finding data is concerned unless you find some sympathetic person in the company that originally made/used them.
  10. kellys_eye

    12 volt relay to start a 24 volt motor

    Paralleling relay contacts isn't a good idea as you can't guarantee them both pulling in at the same time - one will ALWAYS take a greater load, even if only for a very brief period, and wear the contacts in no time.
  11. kellys_eye

    How to repair home phone lcd fading/missing numbers

    According to the pictures you post the board-to-display connection is a 'ribbon' type cable - I can see 'tape' holding the ends down. If you power up the display and apply some (light) pressure along the edge of the ribbon - both ends - you may see an improvement in display quality. Careful...
  12. kellys_eye

    3 phase usb or serial controlled motor relay

    Contactors are pretty much 'universal' in that you have to know the kW (power consumption) of the motor you're controlling, coil voltage, number of poles etc before ordering (you can order 'bigger' than you need if you want). Check out this link...
  13. kellys_eye

    3 phase usb or serial controlled motor relay

    Normal practise would be to switch the three-phase with a contactor - the controlling coil of which could be controlled by a USB relay such as this: http://www.ebay.co.uk/itm/5V-USB-Relay-1-Channel-Programmable-Computer-Control-JI-/112448101668?epid=1269192719&hash=item1a2e6ddd24:g:IvEAAOSwHLNZR0J6
  14. kellys_eye

    electronic components buy

    Never heard of Enrgtech - Farnell is very well established. Likewise RS Components, Rapid Electronics, Mouser, Digikey etc etc etc.... there are also some very good 'independents' and specialist suppliers. In my experience (and I have LOADS) there is no such thing as a single source supplier -...
  15. kellys_eye

    Thermistor for a drinks machine

    Can you get the temperature to exactly 25C and do the measurement again? Most thermistors (as replacements) are quoted at this 25C rating and, as a starting point, you need to establish what this is. Ideally you would do the same for 0C too. The thermistor itself is the tiny 'bead' at the end...
  16. kellys_eye

    salt water damage

    Use a solution of baking soda to stop the corrosion. Post pics of the internals - close-up and in focus! Getting data off an onboard chip won't be easy.
  17. kellys_eye

    Thermistor for a drinks machine

    The thermistor does not go 'normally closed' - it will vary its resistance with temperature but you need a small circuit to convert this resistance change into a 'switching' signal to turn the heating element on and off. To this end you can use 'any' thermistor - its value will be irrelevant f...
  18. kellys_eye

    12 volt relay to start a 24 volt motor

    Why not use a 24V relay? https://www.google.co.uk/search?q=24V+50A+relay&source=univ&tbm=shop&tbo=u&sa=X&ved=0ahUKEwjEzoDGut7VAhUJbVAKHcfyDgQQsxgIJw&biw=1855&bih=1071
  19. kellys_eye

    I-V characterizer

    I don't know what you are asking? Please explain.
  20. kellys_eye

    MOSFET equivalent

    Try looking at CPC Farnell - the 'public' outlet for Farnell proper and they offer parts in quantities of 1 off.
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